ECOLOGICAL AND PHYSIOLOGICAL FACTORS
AFFECTING MATE-FINDING AND MATING BEHAVIOUR
OF DELIA ANTIQUA (MEIGEN) (DIPTERA: ANTHOMYIIDAE)
R. S. MCDONALD
B.Sc., University of Lethbridge, 1977
M.Sc. Universrty of Guelph, 1986
Post Baccularate Diploma, Simon Fraser University, 1991
THESIS SUBMITTED IN PARTIAL FULFILLMENT OF
THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
in the Department
of
Biological Sciences
Q Robert Stuart McDonald 1995
SIMON FRASER UNIVERSITY
August 1995
All rights reserved. This work may not be reproduced in whole or in part, by photocopy or other means, without permission of the author. Frontispiece: Mating sequence of Delia antiqua (Meigen), (Diptera: Anthomyiidae)
APPROVAL
NAME: Robert Stuart McDonald
DEGREE: DOCTOR OF PHILOSOPHY
TITLE OF THESIS:
ECOLOGICAL AND PHYSIOLOGICAL FACTORS AFFECTING MATE-FINDING BEHAVIOUR OF DELIA ANTIQUA (MEIGAN) (DIPTERA: ANTHOMYIIDAE)
Examining Committee:
Chair: Dr. M. Mackauer, Professor
Dr. J.'Borden, Professor, Senior Supervisor, Department of Biological Sciences, SFU A
Dr. WHaunerland, Associate Professor Department of Biological Sciences, SFU
Dr. H. Pierce jr., Research Associate Department of Chemistry, SFU
//L --I -- Dr. R.Vernon, Research Scientist Agriculture Canada Public examiner
r~iller;kdftkor ' Department of Entomology, Michigan State University VExternal Examiner PARTIAL COPYRIGHT LICENSE
I hereby grant to Simon Fraser University the right to lend my thesis, project or extended essay (the title of which is shown below) to users of the Simon Fraser Univeristy
Library, and to make partial or single copies only for such users or in response to a request from the library of any other univerisrty, or other educational institution, on its own behalf or for one of its users. I further agree that permission for multiple copying of this work for scholarly purposes may be granted by me of the Dean of Graduate Studies. It is understood that copying or publication of this work for financial gain shall not be allowed without my written permission.
Title of ThesisfProjectJExtended Essay:
Ecological and Physiological Factors Affecting Mate-finding and Mating Behavlour of
Delia anfiqua (Meigen) (Diptera: Anthomyiidae)
Author:
(signature)
Robert Stuart McDonald
(name)
August 14, 1995
(date) ABSTRACT
Adult onion flies, Delia antiqua (Meigen), were studied from eclosion to sexual maturity, to assess the impact of ecological and phys~ologicalfactors on mate-finding, and mating behaviour.
Protandry (male eclosion in advance of females) resulted from disparate pupal development times between the sexes. The postulation that protandry is an adaptive strategy providing reproductive benefits to either sex is equivocal for D. antiqua because eclosion curves of pupae were normally distributed and mean time-lags in eclosion peaks between the sexes were too short (<4 d) to optimize any reproductive benefits from early sexual maturation or mating. The alternative hypothesis is presented that protandry is a non-adaptive outcome of selection for other life history traits that is unbiased by female size dimorphism. Mating behaviour was age- dependent for both sexes. Few males or females were sexually mature at 3-4 d post edosion, however, >50% of adults aged 6-7 d mated. Although at this time, oocytes were normally 150% of their final egg volume, ovarian development was only weakly correlated (r = 0.48) with frequency of mating. Previtellogenic females, however, were rarely inseminated, suggesting a dietary association with sexual receptivity. In contrast, sucrose feeding by adult males over 10 d had no effect on the proportion of gravid females inseminated over 24 h (-5 females per male), the magnitude of the ovipositional response, or the total numbers of eggs deposited in comparison with males fed protein-rich diet. Upwind response by virgin females aged 410 d to onion dour in a wind tunnel was comparable to that of gravid, mated 10-d-old females, but male upwind response increased linearly with age (? = 0.98), and was inhibited in sexually mature males by the presence of mature females in the wind tunnel. In the absence of host dour, males, but not females, were attracted upwind to conspecifics. Since upwind response to onion dour was independent of ovarian development or mating status, the host-plant probably serves to situate females to their oviposition sites, and males near females. Male courtship and mating behaviour fdlowed a sequence that apparently involves visual recognition of a potential mate, and then species- and sex-specific chemical recognition. Solvent extracts of cuticular volatiles from mature, gravid females, elicited significantly more contact and mating attempts than extracts from immature females or sobent controls. Unique, age-related, C28 methyl-branched alkanes in the extracts of sexually mature females may act as a contact recognition pheromone.
An understanding of age-related phenomena affecting mate-finding and mating behaviour under laboratory conditions may enhance the management of D. antiqua in commercial onion production if D. antiqua adopt a land-mark based, male-controlled mating system in nature.
Integration of chernosensory cues from the host-plants and sex pheromone could lead to improved techniques for monitoring or attracting adults. With incorporation of control measures, such synthetic cues could potentially disrupt mate-finding and mating, especially to the spring generation of aduRs, when competition from naturally-occurring attractants is lowest. DEDICATION
To E. ti., J. A. and S. ACKNOWLEDGMENTS
I wish to express my appreciation to my senior supervisor John H. Borden for generous support and assistance during the course of study and preparation of this thesis. Furthermore, I am especially grateful to the following technical staff at Simon Fraser University: Akbar Syed
(Department of Biological Sciences) for providing consistently high quality D. antiqua and rearing supplies on demand; the late Roger Turner and Les Wakida (Science Technical Centre) for construction and modifications to the design of the wind tunnel and glassware, respectively; Greg
Owen (Department of Chemistry) for mass spectrometry; Elizabeth K. Carefoot (Instructional
Media Centre) for preparation of the frontispiece; and Victor Bourne (Biological Sciences) for assistance with photography. Jay Whistlecraft (Research Branch, Agriculture Canada, London,
Ont.) generously provided cultures of D. antiqua for comparison during the course of this study.
The technical assistance of undergraduate students Michelle A. Thon, Joanne Scherba,
Christa Scott, Carmen Pon, and Paul Mah during the development stages of many bioassays, and referencing much of the literature for the appendix is most appreciated. I also thank my friends and colleagues of the Chemical Ecology Research Group and environs surrounding
86220, whose affabilrty made my time here so enjoyable.
Finally, I would especially like to acknowledge my committee members, in particular Harold
D. Pierce Jr. (Department of Chemistry) who provided technical advice and assistance for many of the pheromonal investigations and James R. Miller (Michigan State University, East Lansing,
MI) and Robert S. Vernon (Research Branch, Agriculture Canada, Vancouver, B.C.) for critical review of the thesis. This study was supported in part by a grant from the Natural Sciences and
Engineering Research Council of Canada. TABLE OF CONTENTS
Page
APPROVAL ...... ii
ABSTRACT ...... iii
DEDICATION ...... v
ACKNOWLEDGEMENTS ...... vi
TABLE OF CONTENTS ...... vii
LIST OF TABLES ...... xi
LIST OF FIGURES ...... xii
1. INTRODUCTION ...... 1
1.1 BIOLOGY AND MANAGEMENT OF DELIA ANTIQUA ...... 2
1.2 THESIS OBJECTIVES ...... 8
2. THE ROLE OF PROTANDRY AS AN ADAPTIVE REPRODUCTIVE
STRATEGY
INTRODUCTION ...... 10
MATERIALS AND METHODS ...... 13
RESULTS ...... 16
DISCUSSION ...... 32
vii 3 . THE RELATIONSHIP OF AGE AND OVARIAN DEVELOPMENT TO
MATING
3.1 INTRODUCTION ......
3.2 MATERIALS AND METHODS ......
3.3 RESULTS ......
3.4 DISCUSSION ......
4 . DIETARY CONSTRAINTS ON SEXUAL RECEPTIVITY. MATING
SUCCESS. AND MALE SURVNORSHIP
4.1 INTRODUCTION ......
4.2 MATERIALS AND METHODS ......
4.3 RESULTS ......
4.4 DISCUSSION ......
5 . HOST-SEEKING AND UPWIND ANEMOTAXIS IN RELATION TO
AGE. OVARIAN DEVELOPMENT AND MATING STATUS
5.1 INTRODUCTION ......
5.2 MATERIALS AND METHODS ......
5.3 RESULTS ......
5.4 DISCUSSION ...... 6 . COURTSHIP BEHAVIOUR AND DISCRIMINATION BETWEEN POTENTIAL MATES BY MALES
6.1 INTRODUCTION ......
6.2 MATERIALS AND METHODS ......
6.3 RESULTS ......
6.4 DISCUSSION ......
7 . COMPARATIVE EFFECTS OF AGE AND OVARIAN DEVELOPMENT
ON CUTICULAR COMPOUNDS AND EVIDENCE FOR A FEMALE
PHEROMONE-MEDIATEDCOPULATORY RESPONSE IN MALES
7.1 INTRODUCTION ......
7.2 MATERIALS AND METHODS ......
7.3 RESULTS ......
7.4 DISCUSSION ......
8 . SUMMARY OF CONCLUSIONS OF ECOLOGICAL AND
PHYSIOLOGICAL FACTORS AFFECTING MATE-FINDING AND
MATING BEHAVIOUR OF DELLA ANTIQUA ...... 163
9 . UTERATURE CITED ...... 169 10. APPENDIX
10.1 ANNOTATED REVIEW OF DELIA ANTIQUA FROM LITERATURE
PUBLISHED FROM 1965 .1995 ...... 183
10.1. 1 INTRODUCTION ...... 183
10.1. 2. SUBJECT INDEX ...... 271 LIST OF TABLES
Page Table 1. Mean development times of male and female larvae and pupae of Delia antiqua reared at 22•‹C* 0.5"C (Exp. 1). 18
Tabk 2. Mean development times of male and female larvae and pupae of Delia antiqua reared at 12 - 22•‹C * OS•‹C, 8:16 h (Exp. 2).
Tabk 3. Mean development times of male and female larvae and pupae of Delia antiqua reared at 22•‹C* 0.5"C, with eggs at 4•‹C for 24 h (Exp. 3).
Tabk 4. Correlation anatysis of pupal weight with range of larval or pupal development times of Delia antiqua reared at various temperature regimes under laboratory conditions.
Table 5. Descriptions of 10 laboratory experiments examining rate of ovarian development and sexual receptivrty of male and female Delia antiqua at varying chronological ages in single and group pairings for 24 h.
Tabk 6. Stages of egg follicle development in Delia antiqua.
Table 7. The percentage of Delia antiqua females at a range of post-eclosion ages inseminated by single 64-old males in 2-choice bioassays over 24 h (Exp. 9).
Tabk 8. The percentage of Delia antiqua females at a range of post-eclosion ages inseminated by single 64-old males in 2-choice bioassays over 24 h (Exp. 10).
Tabk 9. Percentage of female Delia antiqua inseminated and ovipositional response in single pair matings for 24 h with males on varying larval and adult diets (Exp. 1).
Table 10. Effect of sucrose-feeding by male Delia antiqua on the percentage of females mated and ovipositional response in 10:l F:M pairings for 24 h (Ew.2).
Tabk 11. Descriptions of experiments set up to examine the response by sexually mature Delia antiqua to conspecific males and females aged 6-10 and 10-14 d, respectively, or cuticular extracts therefrom. LIST OF FIGURES
Page
Figure 1. Life cycle of Delia antiqua. Annual, three-generation model in 6 Canada is compiled from field data of Treherne & Ruhman (1920), Gray (1924), Penon & Lafrance (1 961) and Liu et a/. (1982). Numbers between arrows represent days required for the development of egg, larval, and pupal stages, and time to first oviposition, in relation to cooler spring and warmer summer conditions. The mean longevrty of adult males and females is 33 and 53 d, respect~ety(Perron & Lafrance, 1961).
Flgure 2. Number of 108 adult male and 87 adult female Delia antiqua 2 4 edosing from non-diapause pupae (a) and cumulative eclosion (b) at constant 22•‹C in Expt. 1. Asterisks above paired bars in Fig. la indicate a significant difference between males and females, two-tailed binomial test, Pc0.05.
Figure 3. Number of 148 adult male and 148 adult female Delia antiqua 2 6 edosing from non-diapause pupae (a) and cumulative eclosion (b) at alternating 22"-12•‹C in Expt. 2. Asterisks above paired bars in Fig. 3a indicate a significant difference between males and females, two-tailed binomial test, P<0.05.
Flgure 4. Number of 115 adult male and 86 adult female Delia antiqua 29 edosing from nondiapause pupae (a) and cumulative eclosion (b) at a constant 22•‹C in Expt. 3 compared with numbers (c) and cumulative eclosion (d) for 46 males and 33 females arising from eggs subjected to 22•‹C preceeded by storage of new-deposited eggs at 4•‹C for 24 h. Asterisks above paired bars indicate a significant difference between males and females, two- tailed binomial test, P<0.05.
Figure 5. Number of 185 adult male and 204 adult female Delia antiqua 31 edosing from diapause pupae (a) and cumulative eclosion (b) at constant 22•‹C in Expt. 4. Asterisks above paired bars in Fig. 5a indicate a significant difference between males and females, two-tailed binomial test, Pc0.05.
Figure 6. Effect of female grouping on mean ovarian development of Delia 49 antique reared in small (A) and large (6)arenas. Probability of significant differences between paired means (t test) is indicated by: NS, A0.05; *, Pd.05; *, P<0.001.
xii Flgure 7. Mean development of eggs in female Delia antiqua held in large 52 arenas for up to 10 consecutive d post-eclosion in isolation or allowed non- mating or mating contact with like-aged males. No significant ddferences between groups of three means. ANOVA, PA.05.
Figure 8. Mean development of eggs in female Delia antiqua held for 3 or 6 54 consecutive d post-eclosi in isolation or allowed non-mating contact with immature or mature males 3 or 6 d of age at start of experiment, respectively. No significant differences between means within groups of three. ANOVA, A0.05.
Flgun 9. Percentage of inseminated Delia antiqua females in single 24 h 56 pairings in small or large arenas with both sexes of the same age at the start of the experiment (A), male age varied from 1-10 d post-eclosion with sexualty mature females 10-12 d post-eclosion (B), and males at receptive age of 6 d and female age varied from 1-10 d post-eclosion (C). Asterisks indicate significant differences between paired percents, Fisher's exact test, P Flgun 10. The mean percentage of inseminated Delia antiqua females of 58 variable age heM for 24 h in large arenas in groups of 10 with 10 sexually mature, 6-d-OMmales. Flgun 11. The cumulative frequency distribution of Delia antiqua females 62 inseminated at ages varying from 1-10 d post-emergence by sexually mature, 64-old males in relation to categories of egg development for females held in grwps of 10:10 females:rnales and for females held in single pairs in large- arena bioassays. Fbun 12. (A) Effect of sucrose feeding by female Delia antiqua in Exp. 3-6 79 on Percent mating in 24 h nechoice and choice bioassays with paired males and females, or (B) with males given the opportunity for polygamous mating. Significant difference (Utest) in percent females mated in Exp. 4 indicated by * (U = 86.5; df = 10, 10; P<0.001) and in Exp. 6 by (U = 44.3; df = 7, 7; P Flgure 15. Relationship between age of virgin female Delia antiqua and 98 percent of the test population trapped in unbaited, control (A) or onion-baited (6) ports in a wind tunnel with an air speed of 8.0 cm per s. The pooled response of gravid, mated 10-d-dd contrd females, tested together in paired bioassays, is indicated by the dashed line. Different letters above bars within each figure panel indicate a significant difference, Student-Newman-Keuls test, Pc0.05. Flgure 16. Relationship between age of virgin male Delia antiqua and percent 100 of the test population trapped in onion-baiied or control ports in a wind tunnel withanairspeedof 8.0crnpers (n= 100-400). Flgure 17. Percent of 10-d-dd, sexually mature, virgin male and female 102 Delia antqua, trapped in onion-baited or control ports in a wind tunnel with an air speed of 8.0 cm per s when sexes were tested separately (Exp. 7) or together (Exp. 8) (n = 300) over 2 h. Differences between paired bars (G test) indicated by: NS no significant difference; P<0.05; - P<0.001. Figure 18. Percents of 10-d-old virgin (Exp. 9) or mated, (Exp. 10) 104 previtellogenic Miaantique females trapped in onion-baited or control ports in a wind tunnel with an air speed of 8.0 cm per s compared with the percent of mated, gravid 10-d-dd females trapped. Differences between paired bars (G test) indicated by: NS no significant difference; Pc0.05; - P<0.001. Flgura 19. Cylindrical bioassay chamber used to observe courtship and mating 114 behaviwr by Delia antiqua. A = video cassette recorder and television monitor; 6 = video camera; C = position of tethered target insect; D = microcomputer with event recorder; E = halogen unit; F = glass cylinder. Enlarged target insect shows placement of the No. 000 insect pin tethering it in an inverted position on a mesh netting substrate. Figure 20. Description of categories of courtship behaviour by Delia antiqua 118 males. Numbered sequence from top left to lower right includes I), aerial inspection; 2), contact from substrate or air; 3), genital positioning; 4), final s&ge of genital alignment; and 5), copulation. Position of female wing is altered for clanty. xiv Flgure 21. Relationship between time and frequency of mating attempts by 20 Delia antiqua males on a tethered female over 2 h in Exp. 1, and 1 h in Exp. 2-4 (24 pooled contrd replicates). Flgure 22. Duration in copulo for 48 matings of Delia antiqua in Exp. 1 and 183 matings in the 24 poded contrd replicates from Exp. 2-4. Flgure 23. Differences in Exp. 2 in the frequency of courtship behaviours of 20 Delia antiqua males exposed for 1 h to a tethered 10-d-old D. antiqua female or to a tethered male (n = 8). Differences between paired bars (Friedman's test) indicated by: *, Pc0.05; ** P Figure 24. Differences in Exp. 3 in the frequency of courtship behaviours of 20 Delia antqua males exposed for 1 h to a tethered 10-d-old D. antiqua female or to a tethered 24-OM female (n = 8). Drfferences between paired bars (Friedman's test) indicated by: *, Pc0.05; ** P<0.01; NS, not significant. Flgure 25. Differences in Exp. 4 in the frequency of courtship behaviours of 20 Delia antiqua males exposed for 1 h to a tethered 10-d-old D. antiqua female or to a tethered 10-d-old female D. radicum (n = 8). Differences between paired bars (Friedman's test) indicated by: +, Pc0.05; * P<0.01; NS, not significant. Flgure 26. Upwind response in a wind tunnel by Delia antiqua males given a choice for 2 or 6 h between blank control ports and ports baited with sexually mature D. anbqua males (Exp. 3, 4) or females (Exp. 5, 6), or given a choice between ports baited with males and females (Exp. 7, 8). Drfferences between paired bars (binomial test) indicated by: **, P<0.01; - P<0.0001; NS, not significant. Flgure 27. Effect of excision of funicles (Exp. 9) or aristae (Exp. 12) on Percentage of female Delia antiqua inseminated over 24 h. Dashed line indicates percent insemination in control matings by pairs of intact flies. Differences from mating by intact control flies (Friedman's test) indicated by: NS, no significant difference, A0.05; ", P<0.01; and -, P<0.001. Figure 28. Chromatograms of the cuticular compounds of Delia antiqua males (6.4 fly equivalents). Anows with letter plus numerals indicate the major peaks for the n-alkanes pentacosane (C25), hexacosane (C26), heptacosane (C27), and octacosane (C28). Anows with numerals only indicate unknown compound found in significantly higher quantities in 10-d-old males fed a normal protein-fich diet than in similarly aged and fed females (Fig. 29). Figure 29. Chromatograms of the cuticular compounds of Delia antiqua 155 males (-0.4 fly equivalents). Anows with letter plus numerals indicate the major peaks for the n-alkanes pentacosane (C25), hexacosane (C26), heptacosane (C27), and octacosane (C28). Compound 1 was found in greater amount in normally aged and fed males than females (Fig. 28), and compound 2 is specific to females. Figure 30. Contact response of Delia antiqua males (n = 10) in Petri dish 157 arenas to pseudoflies treated with cuticular extract of 2- or 10-d-old femlae Delia antique (2.0 FE per pseudofly). Differences between paired bars (Wilcoxon two-sample test) indicated by: *, P<0.01; NS, not significant, A0.05. Flgun 31. Differences in the frequency of courtship behaviours of Delia 159 antique males (n = 20) exposed for 1 h to a tethered cadaver of a 2-d-old female treated with hexane or 4 FE of cuticular extract of 10-d-old mature gravid female D. antiqua. Differences between paired bars (Friedman's test) indicated by: *, Pc0.05; * P<0.01; NS, not significant, A0.05. ECOLOGICAL AND PHYSIOLOGICAL FACTORS AFFECTING MATE-FINDING AND MATING BEHAVIOUR OF DELM ANTIQUA (MEIGEN) (DIPTERA: ANTHOMYIIDAE) 1. INTRODUCTION Reproductive success among insects is the outcome of an assemblage of physiological and ecological factors, including the spatial and temporal constraints imposed on pest species inhabiting seasonal agroecosystems (Chqman, 1982; Liss et a/., 1986). Males of many Diptera optimize their reproductive finess through intrasexual selection, e.g., often by emerging before females (protandry), achieving reproductive maturii early in adult life, limiting the search for mates to a time or location which increases the rate of encounter, releasing chemosensory or other courtship signals, and mating promiscuously (Downes, 1969; Fletcher, 1977; Parker, 1978; Burk, 1981; Thornhill & Alcock, 1983). Female mating sytems are no less complicated. When sexual behaviour is mediated by a female-produced pheromone, considerable attention has been focused on the mechanisms of pheromone production and reception, especially for pest species (Blomquist eta/.;1987; Mayer & Mclaughlin, 1991). Behavioural evidence over the past three decades has demonstrated that a complex array of visual, tactile, chemosensory, and acoustic modalities is employed for sexual communication (Dethier et al., 1960; Shorey, 1973, 1977; Ewing, 1984; West-Eberhard, 1984; Phelen, 1992). Yet rarety have researchers attempted to investigate the physiological basis of mating behaviour, or to conduct studies involving multiple sensory modalities. Without such studies mating systems will be poorly understood, and the potential to manipulate mating behaviour in an agroecosystem may be compromised. This thesis attempts to address the above deficiencies in an integrated study of mating behaviour by the onion maggot, Delia antiqua (Meigen), a cyclonaphous Diptera in the family Anthomyiidae. 1.1 BIOLOGY AND MANAGEMENT OF DELIA ANTIQUA Delia antiqua has evolved from a saprophytic ancestor (OMroyd, 1964) to become a true specialist herbivore (Schneider et a/., 1983), and the most destructive pest of cultivated Allium spp. in the world (Hill, 1987). In an agroecosystem characterized by abundant host-plants grown in monoculture, and few natural enemies, feeding by larvae of D. antiqua on rods or storage shoots of cultivated Allium spp. regularly leads to serious reductions in yield and harvest quality, unless control measures are implemented. Chemical control agents, however, are increasingly ineffective because of resistance (Harris et a]., 1982), and their widespread use is becoming unacceptable to producers and consumers (Eckenrode, 1988; Finch, 1989). Most alternative suppression tactics demand a complete understanding of pest biology. Over 1,850 documents on the life history, biology, and management of 0.antiqua have been published from the mid 19th century onwards (Scott, 1969; Appendix 1). With respect to the need for biological knowledge to manage D. antiqua effectively, the following are salient features of the biology and management of this species. Delia antiqua is widely distributed with cultiiated Allium spp. throughout the northern hemrsphere, including temperate North America, the United Kingdom, central and eastern Europe, the fomr Soviet Union, and parts of south-east Asia (Loosjes, 1976; Hill, 1987). Female D. antiqua are stimulated to oviposit only by stimuli released by Allium spp. (Lilliaceae). In descending order of preference these species are: onion, A. cepa L.; shallot, A. ascalonicum L.; leek, A. porrum L.; chive, A. schoenoprasum L.; garlic, A. .sativum L.; and Japanese bunching onion, A. fistulosum L. (Ellis eta/., 1979; Miller et al., 1984); based in part on a preference for propyl disulfide-producing Allium hosts over ally1 sulfide-producers. Because D. antiqua larvae can be successfully reared on meridic diets (Allan & Askew 1970, Ticheler, 1971) or bacteria (Eyman & Friend, 1983, 1985), host specificrty must be governed by token stimuli rather than nutrients specific to Allium spp. In the laboratory, female D. antiqua can lay up to 700 eggs (Allen & Askew, 1970; Vernon 8 Borden, 1979), yet under field conditions, estimates of the fecundity of individual females varies from -24-58 (Perron & Lafrance, 1961) to -100 (Loosjes, 1976). Development from egg to adult requires a threshold of 4.3OC (Ishikawa et a/., 1987, but fecundity, oviposition, and survival are extremely variaMe under different temperatures (Miles, 1958; Robinson & Zurlini, 1979). At 20•‹C, eggs hatch in 3.1 d, three larval instars develop over 15.5 d, and adults emerge from puparia after 12.2 d (Tolman et a/. 1985) (Fig. 1). The number of generations per year varies from 2-4. Adults overwinter as diapausing prepupae and can withstand temperatures - Eggs are laid in small batches in the soil around !he host plant, especially on volunteer and eaq-mseedlings at higher densites (Gray, 1924; Treherene 8 Ruhman; 1920). Newly- ecbsed first-instars migrate to the onion rhizosphere in response to host kairomones or colonizing bacteria on the infected host (Ikeshoji et a/., 1980), penetrate the stem at the base of adventitious roots, and feed inside the onion bulb (Ikeshoji et a/., 1981). Seedlings attacked at or beyond the 'loop' stage (within 4 wk of sowing) are frequently killed (Treherne & Ruhman, 1920; Miles, 1953, 1955) and spring generation larvae account for 65% of total damage occurring mainly from midJune to midJuly in North America (Whitfield et al., 1985). Damage to older plants, although usually non-lethal, can result in misshapened bulbs and sec~ndaryinfection which lower harvest quality and storage potential. To control D. antiqua larvae and adults, chemical insecticides are applied to seeds (ethion), in furrows (carbofuran, lorsban, or dyfonate), or to foliage (dibrom, diazinon, parathion or cypremethrin) from mid-March to within days of harvest (British Columbia Ministry of Agriiukure, Fisheries and Food, 1991). However, D. antiqua has developed resistance to all major classes of insecticides and chemical control is becoming drfficult (Harris etal., 1982). Adoption of alternative control tactics has been limited largely because they lack the short-term potency or convenience of insecticides (Finch, 1989). Prediction of adult flight periods using thermal sums, occurrence of flowering by common weeds, and monitoring adults captured on sticky traps can be used to optimize the timing and effectiveness of chemical applications while reducing their frequency (Liu et a].,1982; Vernon et al., 1987; Boivin & Benoit, 1987). Damage from the spring generation may also be reduced by cultural controls such as, crop rotation (Eckenrode, 1988), avoidance of mechanical injury to plants during harvest (Eckenrode & Nyrop, 1986), and removal of damaged bulbs and improved sanitation of cull piles (Finch 8 Eckenrode, 1985). Naturally occurring biological control agents such as predaceous beetles and braconid parasitoids (Gherasirn & Lacatusu, 1977; Tomlin et a/., 1985), fungal pathogens (Carruthers et a/., 1985) and nematodes (Choo et al. , 1988) can suppress populations of larvae and adults under certain conditions. Although mass release of genetically-alteredadult males has been applied with limited success (Robinson et a/., 1980), the sterile male technique has been used successfully in the Netherlands for two decades (Noordink, 1971; Ticheler et al. Flgum 1. Life cycle of Delia antiqua. Annual, three-generation model in Canada is compiled from field data of Treheme & Ruhman (192O), Gray (1924), Perron 81 Lafrance (1961) and Liu et al. (1982). Numbers between arrows represent estimated range of days required for the development of egg, larval, and pupal stages, and time to first oviposition, in relation to cooler spring and warmer summer conditions. The mean longevrty of adult males and females is 33 and 53 d, respectively (Perron & Lafrance, 1961). 1974; Loosjes, 1976; J. R. Miller, Dept. Entomol. Michigan State University, personal communication). Considerable attention has also been directed towards the identification and application of semiochemicals mediating host-finding and oviposition {Matsumoto & Thocsteinson, 1968qb; Dindonis & Miller, 1981a, 1981b; Vernon et a/., 1981; lshikawa et a/., 1981; Miller et a]., 1984; Judd & Borden, 1988, l992a,b). Host-plant volatiles used alone, or as a trap adjuvants, however, are not effective in managing adult populations (Harris & Miller, 1988; Finch, 1989; Miller & Cowles, 1991). Other studies have identified compounds which can deter oviposition in the laboratory (Weins et a/., 1978; Javer et a/.,1987; Cowles et a/., 1989, 1990). Integrated use of chemical deterrents and attractive kairomones in a 'push-pull' tactic shows promise (Miller & Cowies, 1991), but has not yet been developed operationally. Despite extensive research in other areas, the reproductive biology of D. antiqua is poorly understood. Mating has rarely been observed in nature (Loosjes, 1976; Martin, 1981). However, the onset of sexual activity is highly variable under field and laboratory conditions (licheler, 1969; Loosjes, 1976; Tolman et a/., 1985). Several aspects of the reproductive biology of 0. antiqua have been reported from laboratory studies, principally from efforts to improve mass- rearing, to examine gametogenesis, and to test the efficacy of radiation-induced sterilization or genetic alteration on the mating competitiveness of males (Missionnier & Stengel 1966; McCJanahan& Simmons, 1966; Noordink, 1971; Theunissen, 1976; Ketel & van Heermert, 1979; RobinSon, 1980; Martin, 1981; Robinson & Zurlini, 1981; Martin & McEwen; 1982). The identities of cknosensory stimuli, or stimuli involving other modalites, that might be employed to manipuhte behaviour associated with mate-finding and courtship, however, is largely unknown (Bol, 1972). 1.2 THESIS OBJECTIVES To identrfy signals that affect mating behaviour, and hence the phenomenon of mating in D. antiqua, the objectives of this thesis were to: 1) determine if differences in edosion times between the sexes could be viewed as a reproductive strategy providing benefts to males or females, 2) determine if the rate of ovarian development in females is influenced by female or male population denscty, 3) establish the relationship between age and sexual receptivity for males and females in single-pair and groupmatings, 4) determine to what extent ovarian maturation is correlated with insemination, 5) examine dietary constraints on the reproductive success of females and males by comparing the effects of protein-rich and protein-free diet on male mating competency and female receptivity, 6) quantify male potency, measured by the frequency of insemination when provided multiple mating opportunities, 7) examine male survivorship and wing fragmentation as indicators of potential lifetime reproductive success, 8) determine if upwind response to host-odour aids males in finding females in an environment devoid of long-range female stimuli, 9) describe the detailed behavioural repertoire involved in the courtship behaviour of sexually receptive males, 10) compare male courtship directed toward 2- and 10-d-old females, (termed sexually unreceptive and receptive, respectively), to other males, and to females of the cabbage maggot, D. radicum (L.), a closely-related species, 11) examine the relative importance of chemosensory, visual, and acoustic cues on mate- finding and mating behaviour, 12) collect volatiles from flies and compare differences between the sexes in relative chemical composition, 13) examine quantitative effects of sex, age, and diet on the profile of cuticular compounds, and 14) determine the role of cuticular extracts from mature, virgin females as male mating stimulants. 2.1 THE ROLE OF PROTANDRY AS AN ADAPTlVE REPRODUCTIVE STRATEGY 2.1. INTRODUCTION For many insect species inhabiting plant-based temperate agroecosystems, seasonal variations in the distribution and abundance of nutrients, conspecifics, and oviposition sites are important constraints to the life cycle (het a/., 1986). Male survivorship is often especially truncated in temporary habitats, and as a consequence, intense competition among males for access to potential mates can lead (via intra-sexual selection) to the evolution of physiological, morphological, and behavioural attributes which will enhance the likelihood of reaching early reproductive maturity and maximize the number of matings. (Thornhill & Alcock, 1983). One common trait that has been selected in many insect species with discrete generations within seasonal habitats, is protandry, the eclosion and reproductive maturation of males before females (Wiklund 8 Fagerstrdm, 1977'). Delia antiqua likely evolved in patchy environments of wild Allium SPP., but it is now essentially a domesticated herbivore that invades few native hosts outside of the cultivated Allium spp. complex (Finch, 1989). Because the onion agroecosystem can support two to three discrete generations per year, considerable attention has been directed to examining patterns of edosion to predict peak abundance and improve the timing of pesticide applications (Eckenrode et al., 1975; Liu et al., 1982). Adult male D. antiqua are commonly detected a few days earlier than females (Treherne & Ruhman, 1920; Loosjes, 1976), and are captured more frequently than females in em-season monitoring with baited traps or adhesive cards (Eckenrode et a/., 1975; Vernon et al., 1987). This trend could be explained in some cases by a distortion in the sex ratio, or a greater response by males than females to traps throughout the season. However, by monitoring diapause pupae in sleeve cages, Finch el al. (1986) confirmed that 50% cumulative edWn of males preceded that of females by 5 d. In studies of other Delia spp., protandry is highly variable under field conditions. For example, Finch & Collier (1983) found that eclosion patterns of the cabbage maggot, 0,radicum (L.), are male-biased by <7 d, overwintering bean seed maggot, D, florilega (Zetterstedt) are strongly protandrous with 50% eclosion of male pupae preceding females by >21 d (Throne 8, Eckenrode, 1985), whereas, no sex differences in the pattern of edosion of seedcorn maggot, 0.platura (Meigen) have been detected (Throne & Eckenrode, 1985). In the laboratory, protandry is frequently noted in 0.antiqua, and observations of protandry are largely a by-product of experiments designed to improve continuous rearing techniques (Ellington, 1963; Zurlini & Robinson 1978; Tolman et a/., 1985). van Heermert et a/. (1979) found that accumulated differences in the rate of development of 0.antiqua eggs, larvae, and pupae reared at constant temperature (19•‹C) can lead to a mean eclosion peak of males occurring 1 d earlier than that of females, but sex differences in development time through larval and pupal stages were not quantified when temperature was atternated as under field conditions, or pupae were under diapause development. Several theoretical and empirical studies in recent years have examined the causes and effects of protandry as a recurrent phenomenon for insects of diverse taxa. Assumptions that Protandry reduces the probability of inbreeding, or removes unfit males before they achieve reproductive maturrty, are now generally rejected (Wiklund & Fagerstram, 1977) in favour of Causal explanations that protandry is either an adaptive consequence of sexual selection or an 'incidental' or non-adaptive by-product of selection pressures for other life history traits. Growing evidence supports the sexual selection hypothesis that protandry persists as a life history trait for various insect species because it provides males eclosing and reaching sexual maturrty early opportunrty for more matings than late-eclosing males (Bulmer, 1983; Wang et a/., 1990; Wedell 1992). Atternativety, protaidry may ensure that females are inseminated early in adulthood and will have lower pre-reproductive mortalq (Fagerstrijm & Wiklund, 1982). The non-adaptationist explanation, in contrast, contends that protandry occurs as an incidental result of natural selection favouring sexual dimorphism in size or body mass (Wiklund & Solbreck, 1982). Females of many insect species may be larger than males because prolonging the duration of feeding larval stage to achieve larger size increases female but not male fecundty (Thornhill & Alcock, 1983). However, female-biased size dimorphism is not a cause for protandry in some species (Nylin et al., 1993). The reproductive benefits of protandry are not well documented within the Diptera (Thornhill & Alcock, 1983), possibty because life history traits have been examined in only a few (notably pest) species. The life history of D. antiqua, however, has been investigated under laboratory and field conditions (Ellington, 1963; Loosjes, 1976; Finch, 1989). Traits of male polygamy and female monogamy (Martin & McEwen, 1982); and discrete generations with truncated male survivorship which decrease the likelihood of generation overlap (Perron & Lafrance, 1961; Liu et a/.,1982), are consistent with some prerequisites for the evolution of Protandry through sexual selection (Wiklund & Fagerstrijm, 1977; Singer, 1982). In view of the the ancestral biology of D. antiqua, such residual life history traits could have important applications to interpreting eclosion patterns in an agroecosytem. I reasoned that examination of quantitative differences between the sexes in the duration of larval feedings stages and pupal development time under controlled conditions could provide insights into mechanisms employed by males to enhance mating opportunities, and afford an opportunrty to examine life history traits which would strengthen arguments that protandry is driven by sexual selection or is an incidental by-product of other selection processes. My objectives were to: 1) quantify the degree of protandry in the development of D. antiqua larvae and pupae on a synthetic diet under regimes of constant and alternating temperature or diapause; and 2), determine if differences in eclosion times between the sexes could be viewed as a reproductive strategy providing benefits to males or females. 2.2 MATERIALS AND METHODS &-rimenhi Insects. Nondiapausing pupae were obtained from an insecticide- susceptible strain of D. antiqua originating from the Agriculture Canada Research Station, London, Ontario, and reared at Simon Fraser University for >I00 generations on a meridic, larval rearing medium (Tcheler, 1971) with a vitamin supplement (Vernon 8 Borden, 1979). Each genetation is established with at least 1,000adults to minimize inbreeding (Zurlini & Robinson, 1978). Within 8 h of emergence, adults were provided with distilled water, and a diet of sucrose, powdered milk, soya flour, Brewers' yeast and yeast hydrotysate ad libitum (Ticheler, 1971). Rearing and experiments were conducted free from volatile odours of onions in environmental chambers at 22 2 OS•‹C, 60 5% RH, and a LD, 1623 h photocycle. In one experiment, insects were induced into pupal diapause by shortened day-length, in association with low temperature Fohn el al., 1985), and then stored at 5•‹C for 36 wk to ensure completion of diapause development. Individuals of this strain reared under these conditions are comparable with feral in their dispersal and host-selection behaviour under field conditions in British Columbia (Judd 8 Borden, 1 992b). -mental Procedures. Three experiments (Exp. 1-3) were conducted in controlled environment chambers to examine the effect of various temperature regimes on differences between the sexes in the durations from egg deposition to eclosion. Before each experiment, ten 12- to 15d-old, nulliparous females were placed for 6 h per d in separate cages containing an sliced onion stem as an oviposition substrate. At the end of each oviposition interval, eggs were transferred in lots of 20 to glass vials (30 cm3) containing -20 g of a meridic, larval rearing medium (Ticheler, 1971). The synthetic diet did not dehydrate appreciably over the larval feeding period; and pupae can be easily viewed and recovered from this medium. Vials were examined twice daily for pupae commencing 14 d after eggs were placed on diet. Newly-formed pupae were held individually in 22 cm3 vials plugged by moistened cotton. In most cases, pupae were recovered within 8 h of pupation as determined by the colour of the puparium during sclerotization. In a preliminary experiment, pupae were weighed individually to the nearest 0.01 mg on a microbalance (Model H20T, Mettler Instr. Zurich, Switz.) at 4 d intervals. Pupal weight was used as an indicator of adult biomass. Since pupal weight varied little over 12 d when cotton plugs were kept moist, pupae in other experiments were weighed within 7-10 d of pupation. Most adults emerge before 0800 h under field conditions (Loosjes, 1976); therefore, vials were inspected for new adutts within the first 8 h of photophase for each d. The objective of Exp. 1 was to quantify differences in development by sex at 22 0.5"C, 60 * 5% RH, and a photoperiod of 16.8 (L:D) h (Tolman eta/., 1985). A total of 390 eggs from six females was collected over 2 d, and rates of development of larvae and pupae were examined as above. Exp. 2 was similar to the first experiment except that 520 eggs from 10 females were collected and subjected to an attemating temperature regime of 22 + 0.5"C and 12 * OS•‹C, synchronized with a photoperiod of 16:8 (L:D) h. I chose this temperature range to approximate a normal fluctuation in air temperature during mid-season growing conditions. To test the assumption that males spent less time in larval stages than females, and accumulated lower biomass, egg development was delayed 24 h by storage at 4"C, followed by rearing at a coostant 22"C, and compared with eggs reared at constant 22•‹C {Exp. 3). Egg development was delayed by 1 d because differences in mean generation times of males in Exp. 1 and 2 appeared to represent accumulated differences of <2 d between the sexes in the period of egg-larval and pupal development (van Heermert et al., 1979). Therefore, I postulated that larval development should be similar between the sexes and any differences between the sexes in generation time would reflect differences in the duration of pupal development alone. I collected 500 eggs from 10 females for 3 d, hdding 120 of these 1 d at 4•‹C [0.3"C below the development threshold (Ishikawa et a/., 1987)], and then returning them to 22"C, at which the remaining 380 eggs were held. If protandry were an adaptive phenomenon, then development time of male and female post-diapause pupae should equal the sum of egg-larval and pupal development under non- diapause conditions (Wiklund 8 Solbreck, 1982; Singer, 1982). In experiments under non- diapause conditions (Exp. 1-3), 1 found that differences in adun eclosion between the sexes were the result of accumulated differences in the time required for egg-larval and pupal development. Nylin et al. (1993) predicted that if protandry was adaptive, sex differences in eclosion times wouM be the result of postdiapause pupal development alone, and should be less dtfferent than under direct nondiapause development. The objective of Exp. 4 was to compare differences in the pattern of postdiapause edosion between the sexes. Five hundred postdiapause pupae were removed from cold storage, weighed, and placed in individual 22 cm3 vials plugged with moistened cotton. Vials were held at 22 * 0.5"C, 60 * 5% RH, with a photoperiod of 16:8 (L:D) h and examined for newiy-eclosed adults at 1 and 8 h into the photophase of each d. Statistical Analyses. A Shapiro-Wilk's statistic (W) (SAS Institute, 1988) was used to assess notrnalrty in the distribution of edosion patterns for males and females in each experiment. Non-parametric Wilcoxon rank sum or Kruskal-Wallis tests (SAS institute, 1988), followed by Tukey-type non-parametric tests for means comparisons (Zar, 1984), were used to compare differences in development time between the sexes. Pupal weights between the sexes were compared by t-tests, or by an analysis of variance (ANOVA) with means separated by a Student-Newman-Keuls test (SAS Institute, 198.8). Correlation analysis was also used to examine the relationship between pupal weight and the development period of larvae and pupae. In addition, for each experiment, a cumulative frequency distribution of the generation time for each sex was calculated and the normal approximation to a two-tailed binomial test was used to test the expectation of a 1:l sex ratio for each d sampled (Zar, 1984). In all cases, a = 0.05. 2.3 RESULTS Protandry under Constant Temperature. Under a constant 22•‹C in Exp. 1, 82.6% of 322 eggs were viable and hatched within 3 d, 63.3% of 204 larvae survived to pupation, 80.9% of 165 pupae successfully eclosed, and numbers of new adults of each sex were consistent with a 1:1 sex ratio. No significant differences between the sexes in egg-larval development were deteded (2= 1.46, Pc0.14) (Table I), however, pupal duration for males was significantly shorter than that for females (Z = 5.07, P<0.001), causing the male generation time to be significant4 shorter than that for females by 1.4 d (Z= 5.62, P<0.001). Pupal weight of males was also significant4 less than that of females (t = -2.94, df = 193; P<0.005) (Table I),but pupal weight was only weakty correlated with time spent in the larval age (Table 4). Because pupal weight is likety comparable to larval weight at the time of pupation, differences in pupal weight between the sexes probably indicate that males were accumulating less biomass than females in the larval stages. If pupal duration were negatively related to temperature and positively to biomass, then pupae with low biomass should take the least time to eclose. However, no significant correlation in the time required for male pupae to dose in relation to pupal weight was detected (Table 4). The onset of male edosion preceded that of females by 1 d, and patterns of peak eclosion and cumulative edosion were 1 d out of phase between the sexes over a 9 d period (Fig. 2a, b). Ecbsion curves were normally distributed for males (W = 0.89, P<0.14) and females (W = 0.96, Pc0.86). However, edosion was significantly male-biased until 4 d and female-biased after 5 d. From Fig. 2b, edosion of 50% of males and females could be expected at 4 and 5 d, respectively from the onset. Protandry under Alternating Temperature. Rearing 0,antiqua under an alternating temperature regime in Exp. 2 resulted in ddferences in development times between the sexes which followed a similar, but more protracted trend than observed in Exp. 1. In this experiment 85.2% of 443 eggs hatched, 78.6% of 348 larvae survived to pupation, 85.1% of 296 pupae eclosed successfully and equal numbers of both sexes emerged. In contrast to Exp. 1, rearing under alternating temperature caused significant ddferences between the sexes in the mean duration of both egg-larval (Z = -3.23, P<0.001) and pupal development (Z = -6.61, P<0.001) (Table 2). On average, males spent 0.7 fewer days in both egg-larval and pupal stages, culminating in a mean generation time that was significantly shorter (Z = -5.33, P<0.001) by 1.5 d from that of females. Pupal weight of males was also significantty less than that of females (t = -4.00, df = 294; P<0.001) (Table 2), but the only significant correlation of pupal weight with development times was between female pupal weight and duration of the pupal stage. Table 1. Mean development times of male and female larvae and pupae of Deli6 antiqua reared at 22•‹C iO.S•‹C (Exp. 1). Mean iS.E. dsvelopment time (d)l Pupal Sex n egg- larva PUP egg-adult wt (mCl)2 male 108 16.5i0.1a female 87 16.7 * 0.1 a Means in a column followed by different letters are significantly different, Wilcoxon rank sum test P 2~eansfollowed by different letters are significantly different, t-test P<0.001. Table 2. Mean development times of male and female larvae and pupae of Delia antiqua reared at 12 -22•‹CiOS•‹C, 8:16 h (Exp. 2). Mean iS.E. development time (a1 Pupal Sex n egg-larva PUP egg-adult wt (m2 male 148 23.5 i0.2 a female 148 24.2 i 0.2 b 18.0 i0.1 b 42.4 i 0.2 b 13.8 i 0.1 b Means in a column followed by different letters are significantly different, Wilcoxon rank sum test P<0.001. 2~eansfollowed by different letters are signifiiantly different, 1-test P<0.001 Table 3. Mean development times of male and female larvae and pupae of Delia antiqua reared at 22•‹C * OS•‹C, with eggs at 4•‹C for 24-1(Exp. 3). Mean * S.E. development time (d)l Pupal Temperature Sex n egg-larva Pupa egg-adult (ma2 male 115 17.1 * 0.1 a 11.4 * 0.1 a 28.5 * 0.1 a 11.7 * 0.1 a 22•‹C female 86 18.6 i 0.1 b 12.7 i 0.1 b 31.3 * 0.2 b 12.5 +, 0.2 b male 43 19.620.2~ 11.4*0.2a 31.020.3b 11.3*0.3a 4 - 22•‹C female 33 19.720.3~ 12.4k0.2b 32.1 k0.3~ 11.7k0.3a Means in a column fdlowed by different letters are significantly different, Kruskal-Wallis test followed by a Tukey-type m-parametric comparison test, P<0.05. 2~eansfdlowed by different letters are significantly different. ANOVA followed by Student- Newrnan -Keuls test, Pq0.05. As in the previous experiment, eclosion patterns for males and females under alternating temperature were normally distributed (W = 0.94, P<0.54; W = 0.98, P<0.95; for males and females, respectively) (Fig. 3a). The numbers of adults eclosing under alternatmg temperature was significantty male-biased up to 3 d and female-biased after 4 d. Based on the cumulative edosion patterns in Fig. 2b, 50% edosion of males and females could be expected at 3.7 and 5.1 d from the mt. Effect of a 24 h Delay in Egg Hatch on Protandry. As I expected for a transitory temperature-induced delay, the hypothesis in Exp. 3 that differences between the sexes in generation time represented differences in the period of pupal development alone was upheld (Table 3). Of 380 control eggs held at a constant 22"C, 84.4% hatched, 69.5% of 321 larvae survived to pupation, and 90.1% of 201 pupae eclosed successfulty. However, 57.2% of the emergent adults were male, causing a significant deviation from a 1:1 sex ratio (Z = 3.05, P<0.05). Of 120 eggs held for 1 d at 4"C, 81.7% survived to pupation, but 77.6% survivorship of 76 pupae was lower than in the controls. Although 56.6% of the emergent adults from cold- treated eggs were male, this was not a significant departure from a 1:1 sex ratio (Z = 1.58, AO.05). The period of egg-larval development wssignificantty lengthened h2 = 108.5, df = 3; Pe0.001) when egg development was arrested for 24 h, but there was no difference in duration of larval development between males and females (Table 3). The significant difference in pupal duration was similar to that in the controls and those in Exp. 1 and 2 h2= 93.3, df = 3; P<0.001) for both treatments. Total generation time was also significantty different among treatments (x2 = 131.5, df = 3; P Figure 3. Number of 148 adult male and 148 adult female Delia antiqua edosing from non- diapause pupae (a) and cumulative edosion (b) at alternating 22"-12•‹C in Exp. 2. Asterisks above paired bars in Fig. 3a indicate a significant drfference between males and females, two- tailed binomial test. P<0.05. Significant differences in pupal weight among sexes were also detected between treatments (F = 8.81, df = 3, 276; Pc0.001) (Table 3). As in previous expe~iments,mean pupal weight of males was significantty less than that of females when eggs where not temperature delayed, but did not differ significantty from that of either males or females in the cold-treatment group. Pupal weight in both undelayed and cold-treated males was significantly correlated with duration of egg-larval development (Table 4). However, pupal weight was significantly positively correlated with pupal duration only for males from the undelayed treatment. Thus, differences in generation times between the sexes could not be adequately explained by differences in pupal weight alone. Eclosion was extended over an 8 d period from the ooset of first edosion for males of undelayed and cold-treated eggs (Fig. 4a, c), but neither pattern of edosion departed from normalrty (W = 0.96, Pc0.80; W = 0.87, Pc0.13; respectivety). A similar eclosion distribution was observed for females from undelayed and cold-treated eggs (W = 0.86, P<0.06; W = 0.86, P<0.12; respectivety) . Eclosion of adults from undelayed eggs was strongly male-biased up until 5 d, and female- biased after 6 d, The degree of protandry was pronounced, with 50% cumulative male eclosion occurring at 4 d, 3 d earlier than for females (Fig. 4b). A different trend occurred for adults arising from eggs that were temperature-delayed. Eclosion was significantly male-biased up to 6 d, but did not become female-biased until 9 d (Fig. 412).Cumulative 50% eclosion of males and females occurred within 6 and 7 d, respectively (Fig. 44. Flgure 4. Number of 115 adult male and 86 adult female Delia antiqua eclosing from non- diapause pupae (a) and cumulative edosion (b) at a constant 22•‹C in Exp. 3 compared with numbers (c) and cumulative edosion (d) for 46 males and 33 females arising from eggs subjected to 22•‹Cpreceeded by storage of new-deposited eggs at 4•‹Cfor 24 h. Asterisks above paired bars indicate a significant difference between males and females, two-tailed binomial test, P<0.05. Figure 5. Number of 185 adult male and 204 adult female Delia antiqua eclosing from diapause pupae (a) and cumulative eclosion (b) at constant 22•‹Cin Exp. 4. Asterisks above paired bars in Fig. 5a indicate a significant difference between males and females, two-tailed binomial test, PeO.05. Protandry of Diapause Pupae. As in previous experiments, patterns of eclosion were normally distributed for males and females from diapause pupae (W = 0.81, P<0.13; W = 0.89, P<0.37; respectively) (Fig. 5a). Furthermore, survivorship of 389 postdiapause pupae at 77.8% was comparable with that in previous experiments and the sex ratio of eclosing adutts at 22•‹C did nd deviate significantly from 1 :l. While some individuals of both sexes completed post- diapause development in 12 d, differences in the sex ratio at eclosion were significant for males at 12 d (Z = 2.8, P<0.001 ) and for females at 14 d (Z = 6.2, P<0.001) (Fig. 5a). Cumulative 50% edosion for males and females occurred within 1.5 and 1.7 d of the onset of edosion (Fig. 5b), and no adutts eclosed after 4 d. Pooled mean postdiapause pupal development times for 185 males and 204 females at 13.0 * 0.04 and 13.3 i 0.04 d, respectively, were significantly different (Z= -3.8, P<0.001). No significant difference between the sexes in pupal weight was detected on any day of eclosion; pooled mean pupal weights for 185 males and 204 females were 13.6 * 0.1 and 13.7 t 0.1 mg, respectively (t = -0.42, df = 387; P<0.67). However, a weakly significant correlation was detected between pupal duration and pupal weight for females (r = 0.14, Pc0.05). 2.4 DISCUSSION Resub under controlled conditions confirm that protandry is a recurring phenomenon in D. antiqua and is largety an outcome of differences in accumulated time required for males to complete egg-larval and pupal development (van Heermert el al., 1979). 1 would expect that protandry will be constrained by ddferent regimes of temperature, as seen in this study, since develop? ?nt rate in poikilotherms is temperaturedependent. But considerable variation in the degree of protandry occurred at constant temperature, and normal curves of male eclosion (Table 1, 3, Fig. 2, 4; Exp. 1, 3) are not in accord with mathematical models for the sexual selection of protandry which predict a skewed curve favouring shortened development time for males under constant temperature (Wiklund and Fagerstrdm, 1977; FagerstrBm & Wiklund, 1982; Bulmer, 1983). Interpretation of causal factors or the adaptive significance of protandry as a reproductive strategy in nature are complicated by possible subtleties in a laboratory population and the shortage of empirical evidence of edosion patterns under field conditions (Baughman eta/., 1988). Yet, examination of the direction and strength of such phenomena can prowde valuable insights into life his!ory trarts adapted by an organism in response to its environment (Nylin el d., 1993). Prdandry theoretically provides adaptive benefits to males and is reinforced by sexual selection under conditions where: 1) males are polygamous, and have equivalent life expectancies and competitive abilities; and 2) females are typically monogamous and are mated soon after edosion (Wiklund 8 Fagerstrdm, 1977; Fagerstrdm & Wiklund, 1982; Thornhill & Alcock, 1983). In such cases, studies on insects of diverse taxa in natural environments have shown that earty-eclosing males have a competitive advantage over late-eclosing conspecifics through: 1) holding territories which attract a large number of females (Davies, 1978); 2) a longer lifespan (Wang et al., 1990); 3) higher rates of female encounter (Wang et a/., 1990); and 4) greater assurance of patemrty (Wedell, 1992). Male polygny and female monogamy occur in 0. antique (Martin 8 McEwen, 1982), and because adult 0. antiqua aggregate throughout the season at hedgerows near fields of onion (Finch el d.,1986), 1 expect competition for nutrients, shelter, and mates to be in direct proportion to the population densq and the quantrty and quality of resource. Male searches or competive territoral displays are well documented among dipteran species (Fitzpatrick & Wellington, 1982), and in the closely related Hylemya alcathoe (Walker), males aggregate at visual landmarks in places at forest clearings where they encounter receptive females (Alcock, 1983). However, there is currently no documented evidenca that early-eclosing males of 0.antiqua compete with physical aggression for access to receptive females, or occupy and defend high-quality resources and terriitories, thereby encountering more females, which wouM strengthen acceptance of this hypothesis. Furthermore, another key condition of the male-benefit hypothesis, that females are sexually mature and mate relatively soon after eclosion (Wiklund 8 Fagerstrbm, 1977; Thornhill 8 Alcock, l983), is not futfilled for 0.antiqua In a companion study on the relationship between age and sexual receptivity (Chapter 3), 1 found that the minimum time required for males and females to reach maturrty after edosion was 3 d at 22"C, but the majority of individuals of both sexes required 6-7 d to become sexually receptive. I contend that early-eclosing male 0. antiqua would gain no mating advantages if females required an appreciable large time to reach sexual receptivrty. Since mean survivorship of males is lower than that of females by nearly 3 wk under field conditions (Perron & LaFrance, 1961), it seems improbable that sexual selection wouM favour males that risk increased pre-reproductive mortalrty by eclosing well in advance of females, and then wait an additional 6-12 d for females to eclose and become reproductively mature. In cases, then, where females do not mate shortly after eclosion, an alternative male- benefit hypdhesis predicts that selection will result in synchronous patterns of edosion between the sexes, and reproductive matunty rather than edosion will become protandrous (Thornhill & Alcock, 1983). This hypothesis can also be rejected for 0.antiqua because: 1) mean peaks of eclosion were >1 d out of phase in many cases (Fig. 2-4; Exp. 1-3); 2) eclosion patterns between the sexes are not synchronous under field conditions (Finch el a]., 1986); and 3) the duration required to reach sexual maturrty is the same for both sexes (Chapter 3). Adaptive benefits for females that delay edosion include: 1) a shortened time lag between edosion and insemination; 2) decreased risk of pre-reproductive death; 3) increased chance of mating with males with the greatest su~vorship;and 4) close synchrony with seasonal resources and suitable ovipwition sites (Fagerstr6m & W~klund,1982). 1 can not dismiss the first two benefits because earty-eclosing males of D, antiqua would be reproductively mature in advance of females under field conditions, and delayed edosion of females would provide them with a mechanism to ensure mating early in adulthood. Yet given the short period between 50% cumulative edosion of aduRs in this study and under field conditions (Finch et a]., 1986), and a large resident population of polygamous males at hedgerows, it is questionable that any female benefits would be realized. I have no data to support the hypothesis that earty-eclosing males are most reproductively fit or differ in any other aspect from late edosing males. Although there would be a selective advantage for females to synchronize eclosion with the availability of oviposition sites, suitable oviposition sites in early season are determined by cultural practices, which are not necessarily under the same environmental constraints as eclosion. First and second generation females in mid and late season wouM have constantly abundant oviposition sites. Data thus favour the alternative hypothesis that protandry is an incidental effect of selection for other life history characters. Weight of nondiapause pupae being weakly but repeatedly correlated with duration of male development (Table 4, Exp. 1-2), might argue that protandy was a temperature-dependent consequence of selection for sexual size dimorphism (Wiklund & Solbreck, 1982). In some Diptera, small males can have the greatest reproductive success in competition with conspecifics (Mclachh Allen, 1987), and by developing quickly at the expense of large size, larvae may decrease the chance of predation or parasitism (Thornhill & Alcock, 1983; Tomlin et d.,1985). Large D. antiqua females produce the most eggs and have the highest rates of oviposition (Robinson & Zurlini, 1981), but male size is not maladaptive because the size of adult males has no effect on mating success, egg hatchabilrty or male survival under normal rearing conditions (Robinson & Zudini, 1981). Female larvae in this study tended to develop slower than males and had more biomass at the pupal stage, but differences in development time were not sufficiently well correlated with pupal weight to explain the occurrence of protandry adequately (Table 4). Although I have no direct evidence to support the prediction that rates of larval growth were comparable between the sexes (Singer, 1982), a transitory delay in egg development in D. antiqua did negate differences between the sexes in the duration of larval stages, with the result that pupal weight was comparable between the sexes, and female edosion development was delayed (Fig. 4; Exp. 3). Larval growth before the onset of diapause may also have been equitable between the sexes since differences in pupal weight were negligible (Table 1, Fig. 5; Exp. 4). Yet, given that the period required for postdiapause rnorphogenesis was longer for females than males under laboratory and field conditions (Finch et ad,, 1986), variation in edosion in 0.antiqua cannot be explained simply by sexual dimorphism in mass. Nylin el a/. (1993) found a high degree of non- association between protandry and dimorphism in the body mass of pupal and adult stages in a lepidopteran species, whh they attributed to variation in pupal development time and in the relative growth rate of the sexes. Adaptive variation can affect larval growth and development rates among lepidopterans with the result that individuals can optimize their growth without compromising body size (Nylin el d., 1993). An endogenous physiological mechanism also ~bdsr'hythms of edosion in many insect species (Truman, 1972). Since adult D. antiqua For species like 0. antiqua where life history traits likely evolved in discontinuous (i.e. patchy) ancestral habitats under different selection pressure than in seasonal agroecosystems where large populations can be supported, interpretation of the adaptive significance of Protandry is especially difficult. Protandry in 0. antiqua may have no adaptive significance as a reproductive strategy in these seasonal agroecosystems, since they are in evolutionary disequilibrium (i.e. unstable) by design (Lks et a/., 1986), and edosion can easily be offset by local heterogeneity in abiotic factors such as soil structure and temperature which will affect larval growth, pupal diapause and post-diapause morphogenesis (Loos~~s,1976; lshikawa et a/., l987). Patterns of eclosion from the overwintering generation also influence the timing of the first and second generations in mid and late season (Liu el a/., 1982). 1 expect that length of larval feeding, pupal weight, and adult size of both sexes will vary widely in the first and Sukq~entgenerations because of the tendency for females to oviposit On onions previousty infsted with larvae (Treherne & Ruhman, 1920; Ellington, 1963), and temporal changes Occurring in quantity and qualrty of resources can affect relative growth rates of the sexes. Since the field crop environment is not stable from generation to generation, I predict that sexual wlection would not favour strong protandry in seasonal populations of D. antiqua. Protandry, could remain as a residual trait that favours outbreeding or provides other reproductive to a p&ion of the population in the patchy environments where wild AI/iurn spp. existed Prior to the widespread cuttivation of onions and the domestication of D. antiqua. 3. THE RELATIONSHIP OF AGE AND OVARIAN DEVELOPMENT 7'0 MAllNG 3.1 INTRODUCTION Many Diptera require a post-eclosion interval of several days before mating. The factors determining this are numerous and complex. In nature, this pre-reproductive time for both sexes is usually conditional upon: meeting physiological rt?qhXW?nts for vitettogenesis, oogenesis, and maturation of accessory gland secretions (Chen, 1984; Raabe, 1986; Raikhel & Dhadialla, 1992); futfilling the spatial and temporal requirements for many species to lek (Thornhill & Alcock, 1983); synthesizing and releasing pheromone (Blomquist et a/., 1987); and the onset of mating be haviour. Most studies on the timing of sexual receptivity in cyclorraphous Diptera have been in the laboratory where groups of mixed-sex individuals of varying ages are confined under known conditions. Sexual receptivny for both sexes is then evidenced by the presence of Spe!?wdozoa in the female reproductive tract and the timing is usually correlated with distinct Mr~hdogicalstages of ovarian development (Adams & Hintz, 1969; Jones, 1971; Vogt et. a/., 1974). In these studies, females with previtellogenic ovaries were rarely mated, and the ProFWtiOn of females inseminated increased directly with early Stages of 00genesis. Because CWShMtemperature and abundant protein-rich diet will favour optimum ovarian development in anautogenous dipterans (Agui et a/., 1985)' 1 reasoned that other possible priming factors likely loaffect oexual receptivw would be masked under such c~~cu~s~~c€!s.A 'primer' effect of at high densities could be an important source of variation in determining the rate of Ovarian development and the timing of sexual activity for both Sexes, particularly if 'primer' Pheromones or non-chemical cues trigger ovarian maturation (Blum, 1974; Craddock & Boake, 1992). Crowding can also impart several negative effects on adult behaviour in many species (Peters & Barbosa, 1977), and may inhibit endocrine activity when the availability of nutritional components is limited (Raabe, 1986). Much of the information on the reproductive biology of Delia mtigua has been an incidental by-product of research designed to assess the feasibilrty of suppressing populations with mass release of radiation-sterilized or genetically altered males Feunissen, 1976; Robinson, 1980). However, several published accounts of mating behaviour (Loosjes, 1976; Martin, 1981), the age at which sexual receptivity is achieved (Ticheler, 1969, 1971; Broersma & LWmwm, 1968; Theunissen, 1976; Toknan ef a/., 1985), and factors affecting sexual rwe~tivity(Robinson & Zudhi, 1981) are available. Insemination of feral females probably OCcurs 1-2 wks after emergence, presumably after oocyte maturation in terminal ovarioles, and arrival in the vicinity of the host plant (Loosjes, 1976; Judd & Borden, 1988). Visual inspection of females of 0. antiqua with mature oocytes is used currently as a Ph~si010~i~almarker in the field to characterize phenology and population age structure (Liu et el., 1982; Tsutsumi & Mitsui, 1987), and to relate development state with dispersal and mating (Judd & Bwden, 1988, 1992). However, there is little empirical evidence from field or laboratory investigations to support the hypothesis that mature oocytes are a~~urateindicators of =xual receptivity. Higley & Pedigo (1984) and Martinson et d. (1989) examined ovarian in the seedcorn fly, 0. plafura (Meigen) and D. antiqua, respectively, and %Nested that mating stimulated ovarian development, bcause most trapped in the field with mature ovaries were mated. Mating is not required for ovarian development in the fly, D. radkum (L.) (Missonnier & Stengel, l966), but tremendous variability in ovarian development within a speck can occur in anthomyids deprived of mating opportunities or host Plants (Weston et al., 1992; Kostal, 1993). Knowledge of the interval required to reach reproductive maturity is critical in identifying factors influencing mating behaviour, ensuring that bioassays employ individuals of the appropriate physiological state of sexual receptivdy under suitable test conditions, and refining Prediction on reproductive status of field populations. My objectives in this study were to: 1) determine if the rate of ovarian development in females of D. antiqua is influenced by female or male population densrty; 2) establish the relationship between age and sexual receptivrty for males and females in single-pair and groupmatings; and 3) determine to what extent ovarian maturation is correlated with insemination. 3.2 MATERIALS AND METHODS Ekpsflrnental Insects. Adult D. antiqua for all experiments were produced and maintained as Ckscribed in Chapter 2. Mating experiments were conducted free from volatile odours of Onions in environmental chambers at 22" * 1•‹C, 60 * 5% r.h., under fluorescent and tungsten illumination (21,500 lux 1 m), with a photoregime of 16 h light:8 h dark. Effects of female population density on ovarian development. Two preliminary experiments (Table 5, Exp. 1-2)1 examined the rate of ovarian development of individual females in relation a Possible effect of the presence of other females. At the start of each experiment, puparia were placed singly in 22 shell vials containing a moistened strip of filter paper and stoppered Experiment Cross reference number - Experimental setup to results To determine the chronological age of sexual recept~~ltyAs in 5, but pairing males with sexually mature lemales aged 10-12 Fig. 9 for males when females are at a receptive age. d. n = 10 and 20 for small- and large-arena bioasays, respectively. To determine the chronological age of sexual receptrvlty As in 5, but pairing females with sexually mature males aged 6 d. n Fig. 9 for females when males are at a receptive age. = 10 and 20 for small- and large-arena biassays, respectively. To examine the effect of population denslty on As in 7, with group size of 10:lO malesfemales in large arenas. n = Fig. 9 chronological age of sexual receptivity of females at 3. variable age to sexually receptive males. To compare the preference of sexually receptive males Pairing single males aged 6 d in choice- or nochoice, large arena Table 7 for inseminating females at different stages of ovarian biassays with females aged 5 and 7 d over 24 h, followed by development examination of ovaries and spermathecae. n = 20. To compare the preference of sexually receptive males As in 9, with females aged 3 and 8 d over 24 h, n = 10. Table 7 for inseminating females at very different chronological ages. with absorbant cotton. AduRs were sexed 6-8 h after eclosion when food was added. The experimental unit in these and all subsequent experiments was individual, virgin females. In the first, 10-d experiment (Table 5, Exp. I), females were held alone or in groups of five in 22 ml shell vials (termed small-arenas), as developed by Swailes (1961) for mating studies on D. radicum. At 2 d intervals following eclosion, females from each treatment were stored briefly at S0C, then dissected in Levy physiological saline (Theunissen, 1973) to examine ovarian d@velopment. Female D. antiqua have meroistic, polytrophic ovaries with the most mature follicle in each of 150 ovarioles synchronously developing (Missonnier & Stengel, 1966). Ovarian development was classified on a 10-stage scale developed for D. antiqua (Theunissen, (Table 6) by measuring the length of a single terminal follicle to the nearest 0.01 mm with a dissecting microscope fitted with an ocular micrometer. In a second, similar 10-d experiment (Table 5, Exp. 2), females were held alone or in groups of 20 in 750 mil 11 x 6 X 9 cm plastic, 'earing-cages, termed large-arenas. These allowed the flies much more mobility than did the small arenas. Effects of male population density on ovarian development. To investigate a possible effect Of adult males on the rate of ovarian development, two experiments (Table 5, Exp. 3-4) were Conducted. In a preliminary experiment, (Exp. 3) groups of 10 newly-eclosed females were held In large-arena cages as described above. Treatments were: 1) 10 males and 10 females at the Same chronological age in direct contact with each other; 2) treatment 1, but sexes isolated in Separate, split-cage arenas that allowed for possible exchange of chemical, visual or acoustic but prevented direct contact; and 3) a control group of f~tndesconfined in cages maintained in an environmental chamber segregated from tnaks. At 2-d intervals over a 10 d past-eclosion period, 10 females per arena from each treatment were removed to assess ovarian Morphological stage1 Description 2 previtellogenic stage, 3 previtellogenic stage at pupal eclosion, 4 beginning of vitellogenesis, 5 size of oocyte equals that of trophocytes, 6 oocyte up to 25% of volume of nurse chamber, 7 oocyte up to 50% of volume, 8 up to 75% of volume, 9 oocyte greater than 75% of volume, 10 oocyte full-grown, chorion developed. Modified from Theunissen (1973). development. If females had been held with males, spermathecae were excised and examined at 400x for the presence of spermatozoa. 24 h in Exp. 6 with a single receptive virgin female aged 10 to 12 d. TO identrty the age at which fWnales became receptive, virgin females aged between 1 and 10 d post-eclosion were paired singly in ~xp.7 for 24 h with with 6-d-dd receptive males. Pairs at each chronological age in E~P.6 and 7 were tested in both small- and large-arena bioassays. Exp. 8 (Table 5) was conducted to test the hypothesis that high fly densrty might induce or force females to mate at an earlier age than in single-pair matings. Ten, 6-d-dd males were confwd for 24 h in large arenas with 10 females at intervals from 1 to 10 d post-eclosion. The propensity of mature maks to inseminate females of two chronological ages was tested by placing single 6-d-dd males in two-choice or no-choice large-arena bioassays with at initial chronological ages of 4 and 6, or 4 or 6 dl res~edbely(E~P. 9. Table 5) . of different ages were lightly dusted with different fluorescent powders (Dayglo Color Cor~.,Cleveland Ohio). In a similar experiment (Exp. 10, Table 5), 6-d-old males were held with females at chronological ages of 2 and 7 d, or 2 or 7 dl respectively. Statistical Analysis. Data on the relationship of chronological age with ovarian development for female reared in isohtion or in groups were subjected to two-tailed, two- t tests, (SAS Institute, 1988). Egg follicle length was tmfEformed by (x + 0.5)~to 'mprove homoscedasticity of variance (Zar, 1984) before analysis, but data are presented withWt transfocmath. Difference in ovarian development in rekition to presence of sexually Immature or mature males were evaluated by multi-sample analyses of variance (ANOVA) (SAS Iwitute. 1988). For mating experiments, correlation analysis WSalso used to investigate the relationship between follicle length and egg stage and between insemination and egg stage. In addition, follicle length and female age were fitted by several non-linear regression models. Differences in the proportions of females inseminated in small- and large-arena mating bi0a~Sayswere also examined by two-tailed Fisher exact tests (SAS Institute, 1988). A CUmulative distribution of the percentage of inseminated fe~ale~in relation to categories of egg development was plotted for females held as single pairs in large arenas, in choice- and no- choice bioassays, or in groups of 10, and a Kolmogorov-Smirnov two-tailed two-sample D test Statistic was used to compare drfferences between distributions (Zar, 1984). In all cases a = 0.05. 3.3 RESULTS Over the 10 d duration, the regression equation best fitting the relationship between Ovarian development and age for females in large arenas reared in groups of 20 was y = 0.34 + 2.06 x - 0.1 1 *, (C .0.98); where y. mean egg follicle length in mrn and X = female age in days Post-edosion. By comparison, the equations best fitting this relationship for isolated females in large arenas and all females reared in small arenas were y = 0.006 + 0.002~t 0.0004 (p = 0.96) and y = 0.092 + 0.021 x, (C = 0.87). 6. Effect of female grouping on mean ovarian development of Delia antiqua reared in (A) and large (B) arenas. Probability of significant differences between paired means (t test) is indicated by: NS, A0.05;*, P<0.05;*, PcO.001. { A Exp. 1, Small Arena (22 ml) 0 isolaled (n=10) 1 grouped (n=15) 1 B Exp. 2 Large Arena (750 ml) 0 isolated (n=20) grouped (n=20) 2 4 6 8 10 Female Age (days) Effects of male population densily on ovarian development. There was no evidence of a male-induced 'primer' effect on the rate of ovarian development. Nan-mating or being allowed to mate freely with males, from 2 to 10 d post-eclosion, had no significant effect on rate of ovarian development of groups of 10 females in large arenas when conpared with the development of Similar females segregated from males over the same interval (Fig. 7). In a similar comparison, nm-mating exposure to sexually mature males, initialty at 6 d of age, had no effect on the rate of of females over a 3 or 6 d interval in ~0mpari~OfIwith females reared in idation from males (Fig. 8). Age to sexual receptivity. mere was a strong effect of age on the kelihood of females being inseminated (Fig. 9). No adults of either sex mated before 3 d of age. In large-arena bys,with sexes of the same age, in Exp. 5, 15% of females were mated at 5 d and increased to 85% at 6 d (Fig. 94. When receptive female age was held constant at 10-12 d, and male age wss varied in Exp. 6, only one male at 3-d post-~losionmated (Fig. 98). Insemination levels rose gradually between bioassays until 6 d, after which well over 50% Of the males inseminated females (except for 9 d). Two females paired with sexualty mature males in ~xp.7 mated at 4 d post-shion (Fig. 9~),but insemination was infrequent until 7 d, when 85% of females were inseminated. 1 Exp. 3 I O isolaled females (n-10) - 1.0 -1 females near males (n-10) females in contact with males (n-10) Age of Female at End of Interval (days) bure8. Mean development of eggs in female Delia antiqua held for 3 or 6 consecutive d post- eclosi~nin isolation or allowed non-mating contact with immature Or mature males 3 or 6 d of at start of experiment, respectiveb. No significant differences between means within groups Of three. ANOVA, A0.05. Exp. 4 isolated females (n=50) E females near mature males (n=50) Female Age (days) Figure 10. The mean percentage of inseminated Delia antiqua females of variable age held for 24 h in large arenas in groups of 10 with 10 sexually mature, 6-d-old males. Em.8. I -3 arou~edu males and females female age iaried, males mature ...... I2345678910 Female Age at End of Interval (d) Female age E~P. at end of No. fernale Percentage Mean i S.E. Egg setup interval (d) pairs tested inseminateda egg length (mrnlb stage no Choice 5 19 26 0.48i 0.03 6 5 47 NS 0.51i 0.05 NS 6 no choice 7 7 choice Female age &P. at end of No. Cmak Percentage Mean * S.E. Egg setup interval (d) pairs tested inseminateda egg length (mm)b stage no choice 3 3 no choice 8 8 choice 3 8 11. The cumulative frequency distribution of Delia antiqua females inseminated at age varying from 1-10 d post-emergence by sexualv mature, 6-d-old males in relation to categories Of egg development for females held in groups of 10:10 fernales:maks and for females held in Single Pairs in large-arena bioassays. - 10 males with 10 females, n = 105 - o Single-pairs, n = 60 - - - Egg Development Stage Similar results were seen in no-choice and two-choice bioassays (Table 7, Exp. 9). Levels of insemination in females aged 5 or 7 d, when males were given the choice between them, were comparable to th- in no-choice, single-pair matings. I was unable to determine if Sd-old rejected mating attempts by males or if males made no attempts to copulate with them. However, no females aged 3 d were inseminated (Table 8, EXP. 10). These results also that females younger man 4 d post-eclosion are not inseminated. 3.4 DISCUSSION I have no evidence of a male-based 'primer' enhancement of ovarian development, as judged by comparisons with follicle developmental rates of females reared without males, or that follicle maturation war a prerequijte for mating (Higley 1 Pedigo. 1984). Female density, however, appeared to have an appreciable effect on oogenesis. Given that the onset of vitellogenesis among related cyclorrhaphous diptera is activated by the ingestion of suitable Mating behaviour of D. antiqua has not been reported under field conditions and the few available laboratory studies provide little information on factors affecting sexual receptivrty (Martin, 1981). Swarms of male 0. p/atura have been observed in the field (Miller & McClanahan, 1960), and m& aggregations are believed to be a necessary component for mating to occur in the laboratory, since rate of insemination and fecundity increased significantly when females were held in large, mixed-sex groups for a 2-wk period (Hough-Goldstein et at., 1987). HoweVeLincreasing densaies of adun D. antiqua under similar condlions have no effect On mating frequency of females, and can significantly reduce total fecundity and life span for sexes (Robinson, 1980; Zudini & Robinson, 1980). Some female D. antiqua in mixed-sex (Fig. 10) were inseminated at earlier ages than in single pairings in my stucfy, but this acceleration could be the resun of activity of one or a few very aggresive, polygamous males that Perceived and mated with females at the very onset of receptivw (Broersma 81 Luckmann, 1968), Or Could have been due to a effect caused by as~0ciationwith other females (Fig. 6B). I have no evidence of a putative role of swarming in D. antiqua in nature, but insemination r*es in groups in the laboratow were comparable to those in single-pairing in idenh~arena and the propartions of females inseminated at 1-3 d were very low. Because variation in temperature and nutrients are important constraints for D. antiqua in mion-based agroecosystems, especially for adutts of the overwintering generation, my findings be applied to field conditions with care. While insemination of feral females probably Owurs within 1-2 wks of eclosion (Loosjes, 1976), my data do not support the hypothesis that mating occurs after full maturation of oocytes, foliowing dispersal and arrival in the vicinity of the host plant, because mod mated at 6-7 d post-eclosion when WC~~Swere at -stage 7, and no host-plants were available. I believe that visual inspection of mature OOC'~Sis not an aRurate physiologicaj marker to characterize age structure (Liu el dl., 1982; Tsutsumi 81 Mitsui, 1987) or mating status of feral populations (Judd & Borden, 1988, 1992; Maltinson et a/., 1989). The fact that sexual receptivity is age-dependent for both sexes suggests that a combination of developmental, nutritional, and physiological criteria must be met before reaching stages of behaviour leading to initiation of mating behaviour or mate acceptance. In consideration of the of mating in the induction of female monogamy and ovipositional behaviour (Chen, 1984), elucidation of factors mediating sexual attraction and receptivw could lead to improved techniques in monitoring and suppression. 4. DIETARY CONSTRAINTS ON SEXUAL RECEPTIVITY, MATING SUCCESS, AND MALE SURVlVORSHlP Some studies have examined the possibility among the Cyclorrhaphous Diptera that Protein deprivation during aduhhood will affect male reproductive fihless as measured by the development of accessory glands, viable sperm transfer, number of mating% Or potential adult Su~i~orship(Foster, ,967; Anderson, 1978; Morrison et a/., 1982; Jones et a/., 1992). When mahim of the black blow fly,phor~ re@na (Meigen), were maintained On protein-deficient diet, accessory gland elongation was arrested and gland contents failed to mature normally (Stoffdan~,1974), but the impact on male reproductive ffiness was not evaluated. Male D. are polygamous (Martin & McEwen, 1982) and like many other dipterans (Leopold, 1976) PrMuce a complex pr0teinaceous =retion from paragonial glands that is transfered during mating and stimulates oviposition~behaviour (Spencer et €31.. 1992). 1 postulated that if protein '@re removed from the diet of adult male D, antiqua, mating behaviour, normal functioning of 4.2 MATERIALS AND METHODS females from 15 replicates of contrd and sucrose-fed males were transfered to individual Ovipositioo dishes and allowed to ovjposit on an onion shod for 48 h, as described above. Insemination, and egg fertility were recorded for each female. Oviposition response was measured as the difference between the total number of eggs deposited and the number of mature eggs remaining in ovarioles. 4.3 RESULTS Males maintained on sucrose and contrd diets remained free of wing fragmentation for 4 36 and 4-60 d, respeajvejy, with means t SE of 11.0 * 1.4 d and 13.0 * 1.3 d, respectively (n - - 50)* not significantly different (t = 1.03; df = 98; Pc0.30). AS most flies aged, the pattern of vving damage progressed proximally until only the alula and SqUama and mnnants of the costa &ere intact. Males of wings remaining were incapable of sustained flight. This Conditionoccurred in sucrose- and protein-fed males after similar mean durations of 24.7 * 1.2 d (" = l6) and 27.2 * 13 d (n = 22). respectively (f = 1.13; df = 36; Pc0.26)- Age Interval (wk) 4.4 DISCUSSION Lafrance, 1 96 I), respectively]. It has been postulated that D. antiqua mates on the host plant, following ovarian maturation and dispersal to the onion patch (Loosjes, 1976; lshikawa et a/., 1984). My results leato the alternative hypothesis that mating will occur freely at any site where the likelihood of wxually mature adults encountering each other is high. The nutritional benefits to adult 0. miqua feeding on Al/jum spp. in an undamaged vegetative state have not been evaluated to Cmcl~dethat the plant provides no nutrients. However, Inale D. antiqua normally aggregate mar ecjosion adjacent to the sheltered margins of cultivated Allium fields (Finch et a/., 1986) where there is abundant nectar (primarily fructose and Sucrose with some amino proteins, lipids, and (Baker & Baker, 1975; TSlJtsumi 8 Mitsui. 1987). Female D. anti9ua prefer carbohydrate until they are 3 d old, and then become strongly attracted to protein (e.g. enzymatic hydro)ysates of with maximal re- at 8 d of age when ovaries are mature (Niemuyk, 1965). Females attuned to foraging for cdhydrates early in adulthood males and mating at locations rich in nectar, bye gn optimal of e' 9. h8dgerowS at field margins. Mating by D. antiqua males at hedgerow may be comparable to the mating otrategy of Hy/emya dcathoe (Walker), in which lekking males form die1 aggregations at visual landmarks in places at forest clearings where they intercept receptive fe"'es (Alca~k,1 983). 5. HOST-SEEKING AND UPWIND ANEMOTAXIS IN RELATION TO AGE, OVARIAN DEVELOPMENT, AND MATING STATUS 5.1 INTRODUCTION I hypthesjzed that if the host-plant serves other roles than as an ovipositiona~site, in Paic~~ar,as a narient patch or mating site, then odour-mediafed anemofaxisis may be en age- phenomenon for both sexes. I also hypothesued that upwind response to host-dour aid males in locating females in an environment devoid of long-range female stimuli. I 5.2 MATERIALS AND METHODS figurn 14. Diagrammatic side view of the wind tunnel: Arrow indicates direction of air flow. AP - access port, U(H = exhaust tube, HC = holding chamber, V = butterfb valve at point of LA = fluorescent light assemw, LP = left port, 0 = cut onion shoot Or glass rod Suw%ate, RP = right port, and T = trap. treatment to confirm mating status and stage of ovarian development Feunissen, 1973; Table 6). Statistical Analyses. For each experiment three variables Were recorded: 0, the number adults trapped in the onion-bajted port; C, the number trapped in the control port; and n, the total number of aduRs released. From these variables, two additional vahs Were calculated: 1) the Proportion of total number of aduts tested responding upwind to onion odour, [(0 - c)/n];and 2, the proportion of the total number responding upwind, [(O + C)/d. Differences in the Proportions @) between test and control females were pooled and compared in each reWI1se ategory using 2 by 2 G tests for contigency (Zar, 1984). For Exp. 1-4 which assessed upwind '%ponse of females or males in the absence of host odour, a two-tailed binomial test was used to test for bias toward either port, or in cases where s25 flies responded, a two-tailed normal aPpfoximation for the binomial test was used (Zar, 1984). A modified Student-Newman-~euis multiple range test on data transformed by arsine \/p (Zar,l984) Was used to examine differences in the Proportion of unmated females at variable age trapped in the onion-baited and control Ports (Exp 5). In addition, a one-tajled normal approximation to the binomial test Was used to COmParethe number of flies at specific ages (Exp. S), sex (ExP. 7-8) or ovarian development (€*P. 9-10) trapped in the onion-b&ed and control pork CompdSO~in the proportions of gravid, mated females and test flies (EXP.5, 7-10) responding to onion-baited and control ports were Compared by 2 by 2 G testings. The arcsin-transformed prowRion of males at various ages trapped in onion-bajted or control ports (Exp. 6) were anabzed by linear regression, and a "te~twe ured to compare differences between the regresrion coefficients (Zar. 1984). In all a = 0.05. 5.3 RESULTS Although direct behavioural observations on the flight activity of individuals or distribution in the tunnel wanot recorded over time, when released into the wind, most individuals of both WXes turned into the airstream, stationary for several minutes, walked upwind for cm, and then made short (4.5 m) flights into the tunnel. Of the 535 females and 353 males tested (Exp. 3-41, 15.5 and 13.9%. respectively, were trapped. indicating that air flow significantly enhanced catches of both females (G = 25.1, df = 1, P<0.0001) and males (G = 20.1, df = 1, P TI) or males (Z = 1.9, fi0.05, n = 48) intercepted at left or right ports (8.9 and 6.796, for females, and 8.5 and 5.4%, respectively, for males), nor was there a difference in upwind responw between the sexes (G. 0.5, df = 1, R0.48). Flies that remained untrapped the test intecval were througho& the tunnel, b& the nature of this distribution was "Ot assessed. A Trapped in Control Port Trapped in Onion-Baited Port Test Female Age (days) Number of Females Tested in Parentheses Male Age in Days (Number of Males Tested in Parentheses) Males and Females Tested Separately Tested Together Female, n = 300 Female, n = 400 Stimulus 5.4 DISCUSSION It has been postulated that following a pre-reproductive interval for maturation and 0.,tiqua mate at or near the host plant (Loosje~.1976; Ishihwa ef ah. 1984). Judd Bwden (1988, 1992) under field conditions, using mak-recapfure techniques with adults of ,wing age ad reproductive status, a Sequence of events in which both sexes randomly from eclosim sites, obtained suitable nutrients to become sexualiy mature, The response of unmated 10-d-old previtellogenic females to onion odour (Fig. 18) seems falsify the hypothesis of judd & Borden (1988) that the age at which females become to host odour is conelated with the appearance of mature eggs. Females will have mature ovaries at -7 d of age if proteinaceous diet is available and temperature is favorable (Uhnier & Stengel, 1966), ba born sexes can become ~exuallyactive in the absence of dietary pmeh (chapter 4). Furthermore, although previtellogenic, mated females were slightly less responsive to onion dour than gravid, mated females (Fig. 18), there was no other evidence in my experiments to support the hypothesis that the mode of search used by females Changes with mating status (Judd 6 Borden. 1988,1992). 6. COURTSHIP BEHAVIOUR AND DlSCRlMlNATlON BETWEEN POTENTIAL MATES BY MALES 6.1 INTRODUCTION Bol (1972) visually identified six components of the courtship behaviour of male D. antiqua (i.e. Wing fanning, walking, mounting, orientation, copulation attempt, and copulation) which 'Wrnbled the courtship sequence of calypterate muscoids such as the house fly, Musca domicaL., and the face fly, M. &umnaljs DeGeer (Lohda et a]., 1970; Chaudhury & Ball, 973; Tobin & Stoffdano, 1g73a, 197%; Colwell & Show, 1975). However, given the Swiftness, Complexity and infrequency of mating by Mia SPP. (Swdle~,1961 ; 1971; Martin, 1981). Bol (1972) may ndhave ohwed all of the elements that Oc-CUr between the point of male contact with a female contact and copulation. Cinematic or video recording techniques that have been to record the courtship behaviwr of mde muscoid Diptera (Tobin & Stoffolano, 973a, 1973b; CoJwell & Shorey, 1975, 1977; Huyton & Langley, 1982; Wall Langeb, 1993) allow for detailed observation of the mating behaviour of male D. antiqua. Quantitative analyses of the variability in courtship between pairs that mate and those that do not could also provide insights into cues which affect male courtship. Female D. antiqua <3 d OM are rarely mated when paired with sexually mature males (Chapter 3), possibly because Young females have high rates of refusal or a high threshold of attraction to males. Attempts by males to mate with other males, are common in D. antiqua, and other Diptera under laboratory conditions. If males are poor long-range discriminators among conspe~ifi~~and require short- range or contact stimuli to identify suitable mates, then sex-specific stimuli regarding age-related receptivrty among females, could reduce the cost of time males spend searching for or courting unsuitable mates. Here I report the resuks of a laboratory study in which video recording techniques and direct observation, in conjunction with a muftichannel event recorder, were used to: 1) describe the detailed behaviourd repertoire involved in the courtship behaviour of sexually receptive male D. antiqua; 2) compare male courtship directed toward 2- and 10-d-old females, termed Sexually immature and sexually mature, respectively; 3) examine behaviour of males responding Sexually to other males, and 4) to compare the sexual behaviour of male D. antiqua exposed to 10-d-old female D. antiqua and cabbage maggots, D. radicum (L.), a closely-related species with gross morphology and mating behaviour (Swailes, 1961; 1971). 6.2 MATERIALS AND METHODS 24 h of eclosion, placed in separate 26 x 31 x 48 cm screened cages, held at 16:8 L:D under fluorescent and incandescent lighting (21, 500 lux at 1 m), 22 * 1•‹C and 60% RH,and provided ad libitum with a diet of skimmed milk powder, sucrose, Brewers' yeast and yeast hydrolysate With distilled water (Ticheler, 1971). Virgin males and females of D. antiqua and D. radicum used in experiments were aged 7-10 and 10 d, re~pe~tively,to assure optimum sexually activity Or receptivity (Chapter 3 and Swailes, 1971, respectively ). Apparatus Description. Mating chambers (Fig. 19) were constructed from 50 cm long vertical transparent glass cylinders (11 cm OD), which facilitated observation of male behaviour and coud be easily cleaned of excreta between experiments. The top of a chamber was covered by Lumite" netting which diffused light and provided access by the experimenter. The base was a 15 cm OD plastic Petri dish, lined with Whatman No. 1 filter paper moistened to provide water during an experiment. Following Tobin & Stoffolano's (1 973a) method for M. domestics, a live adult was lightb anesthetized by chilling at 5•‹C and then tethered inverted to the top of a chamber by an entomologicd pin (No. 000) inserted into the mesothoracic pleuron (Fig. 19). Adults so restrained were comparable in appearance and behaviour to perched adutts, and could freely use their wings or legs to deter mating attempts. Because exposure to the host plants is necessary for successful mating to occur (Chapter 3), the apparatus was placed in a chamber free from host onion odour, under conditions described above, except that a halogen light unit (Philliw Halogen A, 13649, 150 W) in combination with fluorescent lighting, provided 10,760 lux at 2 cm from the top of the chamber. recorded over 2 h with a Panasoni&, Model WV-CD 110 video camera with a 50 mm macro lens attachment (Pentax@,SMC 1:2.8), centering on the tethered fly. Behaviour was taped at 30 frames per s on a Panasonim, Model AG-1950 video cassette recorder and reviewed in frame- by-frame motion. Morphological descriptions followed Grifiths' (1982) terminology. I considered courtship to be initiated when a male seized the tethered fly, and to end with attempts insertion of the aedeagus. Copulation was timed from the initation of genital contact following mounting of the female to male departure; insemination success Was not assessed. Because male courtship occurred sporadically, a second arena was set Up and operated next to the video arena; a micrecmputer (TmmModel 1100FD) operating an event-recording software Program (Eventlog; Conduit@, Iowa City, IA) was employed to make continuous real-time multichannel recordings of the number of interactions between ex~erimentalmales and the tethered flies, the duration of each interaction, and the relative time during a 1 h session at which the interaction occurred. Although mating occurs in the laboratory throughout the photophase, taping was conducted 7-10 h into the photophase when males were reported to be most active (801, 1972). Experiments. To define male courtship behaviour in Experiment (Exp.) 1, 20 males were transferred to a mating chamber containing a single, virgin, 10-d-old female, and the interactions hwim males and the tethered female were video taped for 2 h. Detailed sequences of behaviour were examined from 48 of the 71 total copulation attempts recorded from eight replicates. Thrw eight-replicate experiments used 1 h visual observations to test differences in behaviour directed toward a tethered control virgin female aged 10-14 d and a test adult of comparable size. Comparisons in courtship by groups of 20 males were examined between control females and normal ir-d-old, sexually mature males (Exp. 2), 2-d-old sexually immature Figure 19. Cylindrical bio-y chamber used to observe courtship and mating behaviour by Delia antiqua. A = video cassette recorder and television monitor; 8 = video camera; C = position of tethered target insect; D = microcomputer with event recorder; E = halogen unit; F = cylinder. Enlarged target insect shows placement of the No. 000 insect pin tethering it in an inverted position on a mesh netting substrate. females (Exp. 3), or normal 10-d-old D. radicum females (Exp. 4). Fresh males and tethered targets were used for each replicate. Statistical Analyses. Means and standard errors were calculated for the durations of Various events recorded to the 0.1 s. The frequencies of copulation attempts over time in Exp. 1, and for the 24 pooled control replicates from Exp. 2-4, were subjected to chi-square goodness of fit tests to determine if frequency followed a normal, Poisson, or negative binomial distribution (Krebs,1989). To compare differences between treatments, a Friedman's two-way analysis for block designs was performed in which the frequencies of behaviour within replicates were ranked and then anabzed for main effects by ANOVA (SAS Institute, 1988). Differences in the in copulo duration between treatments were compared by a Wilcoxon two-sample test (SAS Institute, 1988). In all cases, a = 0.05. 6.3 RESULTS Description of Courtship Events. Seven discrete categories of male courtship behaviour were observed (Fig. 20). Free males and tethered targets exhibited several different behaviours ndrelated to courtship. These included grooming, wing vibrating, and extension and retraction of the proboscis. Inspecbon from Substrate. Courtship behaviour of males often began with inspection of the substrate. M&s approached from any direction to within -1 cm of the tethered female in a swift run along the top of the bioassay chamber, but made no contact. Aerial Inspection. Inspection was also done by wing r'f-talesin extremely short (<0.1 s) and relatively slow (40.0 cm per s) flights from positions on the walls or bottom of the observation chamber to the immediate vicinity of the tethered female without establishing contact. Since males can change the direction of the flight path within 0.03 S, aerial approaches toward the rear or sides of a female were rarely in a straight line. As a male flew towards the female the femora were perpendicular and the tibia and tarsi were fully extended in a grasping position. In some instances when the male rolled or passed across or backwards to the tethered female in the focal plane of the camera lens, the head was orientated to the long axis of the female (Fig. 20). Contact from Subsb.ate. Courtship per se was initiated when the male's prothoracic tarsi touched the body, legs, or wings of the female following a short directed leap, or mating 'strike' from the top of the chamber (Fig. 20). This element rarely exceeded 10 s. In some cases, males followed tarsal contact with proboscal contact to the head (occiput and vertex), thorax (pronoturn and notum), or abdomen. When males mounted females normab (both sexes facing in the same direction), the prothoracic tarsi were first positioned on the notum, the mesothoracic tarsi near the base of the wings, and the metathoracic tarsi on the wings. The male then quickly Shifted backwards making genaal contact possible. Contact initiated from the substrate accounted for 79% of 61 copulation attempts. Some (15%) of these contacts resulted in males mounting females anteridally, then orienting to the normal mounting position. Contact from the Air. Mounting in 21% of the observations occurred when flying males landed on and seized the female (Fig. 20). In some cases, males landed on the ventro-lateral aspect of females, but quickly oriented to the dorsum. Behaviour then proceeded as it did when was made from the substrate. Figure 20. Description of categories of courtship behaviour by Delia antiqua males. Numbered sequence from top left to lower right includes I),aerial inspection; 2), contact from substrate or air; 3), genital positioning; 41, final stage of genital alignment; and S), copulation. Position of female wing is altered for clarity. G8nitalAlignment. In the final precopulatory movement, which frequently occured in <1.0 S with receptive females, the male remained in alignment with the long axis of the female but raised its head so that its bo@ was positioned at an angle of 65-75' when viewed from the side (i.e. male vertical position) (Fig. 20). The prothoracic tarsi of the male were usually placed on the scutellum or the abdominal tergites of the female, separating her wings, and the meso- and metathoracic tarsi were ptessed, respectively, onto the pl~eronof the abdomen, and the abdomen or the substrate. In this position, the male would vibrate his wings rapidly, appearing to help force apart the female's wings. In some cases, males were positioned beneath the wings, which may have allowed greater access to the female genitalia. The external genitalia of the 9th abdominal segment or hypopygium of D. antiqua males are enclosed laterally and dorsally by a large trough-like sclerite, the periandrium ( = epandrium), which bears a pair of cerci, fused along the midline, and a long pair of articulated lobes, the gonostyli ( = surstyli) which project beyond the apex of the cerci (Gfiffdhs, 1982). Genital contact was established when the gonostyli, which rotated in an arc of -1 100, successfully clasped the ovipositor or fully engaged the female cerci. The ovipositor was restrained by a pair of extended lobes attached to the males's 5th abdominal sternite. Occasimally the gonostyli were also used to tap the external genitalia of the female, but I could not determine if this behaviour enhanced the likelihood of genital coupling. Full or Partial extrusion of the four terminal abdominal segments of the ovipositor, which are normalty carried within the female abdomen, was never observed. Copulation. The intromission organ or aedeagus is a complex rod-like structure comprised of lateral sclerites (i.e. paraphalli), in association with distal chitinous processes and membranous areas (Griffjjhs, 1982). From the aedeagal apodeme (= phallapodeme), the site in which strong musculature is attached, the aedeagus was rotated from its anteriorly directed rest Position into the posterior copulatory position. Normally at the onset of intromission, the paraphalli of the aedeagus, which enclose the ejaculatory duct, are inserted past the genital opening at the ventral base of the 8th abdominal segment and into the vagina. The paraphalli ultimately reside in lateral pouches within the bursa copulatrix of the common oviduct where Spermatozoa and accessory gland secretions are released directly into the female from the ejaculatory sac (Price, 1977). From initial genital contact until genital alignment, male wings were in constant motion. However, once the genitalia were attached, both sexes were relatively immobile (Fig. 20). When copulation was completed, the male withdrew his genitalia and dismounted. There was no post-copulatory 'passive stage' (Parker, 1970) of non-genital attachment to the female. The frequency distribution of copulation bouts in Exp. 1 and for the pooled control replicates in Exp. 2-4 (Fig. 21) was best described by the Poisson distribution h2= 801.8, df = 68, P<0.001; and ~2 = 403.8, df = 64, P<0.001; respectively). Peak activlty occurred at 60 min in E~P.1 and 50 min in Exp. 2-4. In Exp. 1, 9.2 * 2.5 copulation bouts (mean _+ S.E., range, 3-20, n = 71) were observed over 2 h. The mating frequency of individual males could not be determined because males were not marked. In Exp. 1 and 2-4, respectively, males spent 70.9 2 20.7 and 30.1 * 4.27 s in copula (range 0.1-681.0 s, n = 48; and range 0.1-540.8 s, n = 183). Long-duration bouts of copulation lasting >50 s accounted for <30% of the observed total in Exp. 1 and 40% in Exp. 2-4 (Fig. 22). Figure 21. Relationship between time and frequency of mating attempts by 20 Delia antiqua males on a tethered female over 2 h in Exp. 1, and 1 h in Exp. 2-4 (24 pooled control replicates). Figurn 22. Duration in cop& for 48 matings of Delia antiqua in Exp. 1 and 183 matings in the 24 pooled control replicates from Exp. 2-4. 35 - Exp. 1 (n = 48) Duration in Copulo (sec) Fig~r'O23. Differences in Exp. 2 in the frequency of courtship behaviours of 20 Delia antiqua males exposed for 1 h to a tethered 10-d-old D. antiqua female or to a tethered male (n = 8). Differences between paired bars (Friedman's test) indicated by: *, P~0.05;* Pc0.01; NS, not significant. c Gravid, 10-d-old female 10-d-old male Q ,, ,, 100 m Substrate Aerial Substrate Aerial Genital Copulation 8 Inspection Contact alignment attempts Courtship Behaviour Female Avoidance Responses. Males positioned near the head of an unreceptive tethered female during the early stages of contact initiated from the substrate or the air, were subjected to a series of upward kicks from the females' prothoracic and mesothoracic legs or fluttering of the wings in a horizontal plane (Fig. 20). If males persevered to attempt genital alignment, the meso- and metathoracic legs were used alone or in combination with wing vibration to prevent the male from spreading the female's wings or to cause him to dismount. Unreceptive females also lowered the abdomen to the substrate, preventing males from making genital contact. Discrimination by Males of Males vs Females. in Exp. 2 (Fig. 23), males approached tethered males and females from the substrate with comparable frequency (F1, 7, = 0.12, 60.74), but, a significantly greater number of aerial inspections were directed toward females than males (F~,7, = 13.2, p P<0.07), but attempted to copulate more with females than males (F1, 7, = 7.0, Pc0.03). The mean durations of copulation bouts on females and males (298.1 * 140.6 vs 11.7 * 7.5 s, respectively) were significantly different (S= 46.5, Pc0.03). Copulation attempts with other males in the biassay chamber represented >50% of the total (1 13.2 * 32.9 attempts), but the Presence of tethered females had no significant effect (F1, 7, = 0.1, fi0.78) On the frequency of Such male-male interaction. Discrimination by Males of Mature vs Immature Females. In Exp. 3 (Fig. 24), males were equally likely to inspect and contact tethered 10- and 2-d-old females from the substrate (F1, 7, = FlgUfe 24. Differences in ~xp.3 in the frequency of courtship behaviours of 20 Delia antiqua males exposed for 1 h to a tethered 10-d-old D. antiqua female or to a tethered 24-old female (n = 8). Differences between paired bars (Friedman's test) indicated by: *, P<0.05; * Pc0.01; NS. ndsignificant. 0.2, A0.63 and F~,7, = 0.6, 60.46, respectively) or from the air (Fl, 7, = 0.4, 60.56 and F~, 7, = 1.9, A0.21, respectively). Nearly 10-fold more genital alignment was achieved on mature, 10-d-old fernales, than on immature, 2-d-old females, but this difference was not significant 7, = 3.2, A0.11). However, the mean number of copulation attempts on control females (2.8 0.92, n = 22, range, 0-8) was significantly greater (F1, 7, = 17.8, Pc0.004) than with 2-d-old fefnales (0.2 * 0.16, n = 2, range, 0-1). Males that attempted copulation also spent significantly mre time (S = 47.0, ~~0.02)in contact with 10-d-old females (54.8 * 31.1 s) than 2-d-old females (2.5 * 2.3 s), but duration of copulation was highly variable. Ahhough the frequency of mating wsexceeding low in chambers with 24-old females, the absence of suitable mates did nd have a significant effect (F,, 7, = 0.02, Pc0.89) on the number of attempted male-male copulations. Overall, a mean of 35.5 * 9.62 male-male interactions occurred over the 1 h test Periods, accounting fw >m%of the total behaviour recorded. Conspecific vs Heterospecific Females. In Exp. 4 (Fig. 251, male inspection and contact from the substrate 2-fold greater towards D. antiqua females than D. radicurn females (F1, 71= 9.9, Pc0.02 and F1, 7, = 12.7, PcO.008, respectively). Inspection and Contact from the air Was lower than from the substrate but did not resuh in discrimination between con- and heterospecific females (F~, 7, .1.2, pc0.31 and F1, 7, = 2.0. Pc0.20, respectively. Once contact wss established, males were 24fold more likely to align genitalia with con- than heterospecjfii females (F~,7, = 43.9, ~~0.0003)and as a consequence, attempted 7.8 1.96 (n = 62) copulation attempts on D. antiqua females compared with only one 0.8 s copulation attempt on a female 0.mdjcurn (F~, 7, = 70.3, P.c0.0001). Time in copulo on D. antiqua females Was extremely variable (mean = 336.6 170.8 s, range, 12.5-1,403.0 5). There were 69.6 i 8.25 male-male interactions per test duration, but no difference in frequency in the presence of Figure 25. Differences in Exp. 4 in the frequency of courtship behaviours of 20 Delia antiqua males exposed for 1 h to a tethered 10-d-old D. antiqua female or to a tethered 10-d-old female D. radicum (n = 8). Differences between paired bars (Friedman's test) indicated by: *, P<0.05; " P<0.01; NS, not significant. Gravid, 10-d-old female 0.antiqua c Gravid, I 0-d-old fem ale 0.radicum a 0 100 \U Substrate Aerial Substrate Aerial Genital Copulation s Inspection Contact alignment attempts Courtship Behaviour 6.4 DISCUSSION This bioassay was designed to provide male D. antiqua a standardized experimental environment, and freedom of movement to inspect or copulate with tethered flies. Video and continuous real-time multichannel recordings of the numbers of interactions involved in courtship facilitated the description and quantification of several previously undescribed male behaviours. It is possible that the of tethered flies may have distorted some elements of male courtship. However, such effects were probably minor, since receptive D. antiqua females typically respond Passively to courting males (001, 1972; Martin, 1981), and tethered flies, awough unable to decamp, were able to avoid copulation attempts in many cases. My descriptions of the repertoire of male D. antiqua courtship behaviour agree with Bok (1972) cursory description of mating by unrestrained pairs. Many of the seven elements of courtship and mating behaviour I observed c!osely resemble the behaviour reported for M. Cbnestica, M. aum&js, the blowffy, Phomia terrae-novae R.-D., and tsetse flies, Glossina SPP- (Murvosh et a/., 1964; Parker, 1968; Lohda et d,1970; Chaudhury 8 Ball, 1973; Tobin & Stoffo~ano,1973a, 1g73b; Cobell & Shorey, 1975; Wall & Lmgley, 1993). In all of these Courtship is initiated with prothoracic tarsal and tibia1 contact with the pronotum, vertex Or occiput of the female, ad is followed in many cases with probing movements with the Woboscis and wing vibraio~from both sexes. Differences between D. antiqua and other SPe~iesinclude the &sence of the 'wing-out' and 'leg-UP' p0sai0n Seen in M.domestica females (Tobin & Stoffolano, 197&), the high degree of 'head-lapping' and Yencing' or 'leg-drummingm seen in M. domesti- and M. autumnalis males (Lohda et a/., 1970; Tobin & Stoffolano, 1973a,b), and the series of 'rubbing' movements with the metathoracic legs near the genitalia of ff3male Glossina conducted by males in the mount position (Wall & Langley, 1993). Female D. antiqua mate only once (Martin & McEwen, 1982), and apparently play a Passive role in the early phases of courtship. Female D. antiqua did not extrude the ovipositor to signal receptivity, unlike female M. domestics or M. autumnalis (Lohda et al., 1970; Tobin & Stoffolano, 197&,b). However, receptive females may do so under more natural condition?. Because females can physically reject courting males or inhibit the transfer of spermatozoa to the spermatheca (Thornhill & Alcock, 1983), the ability by males to grasp and successfully hold a female and remain jn CO@J could affect insemination, imparting a competitive advantage to the most fit males. Furthermore, rubbing and tapping the external genitalia by males can act as a competitive signal for eliciting female acceptance in some species (West-Eberhard, 1984; Otronen, 1990). I do not know if the short-durations in copulo found in many instances for D. antiqua resulted in sperm transfer. However, 75% of copulating male Screw-Worms, C~~hliom~j~ hominivorax (Coquerel), transferred sperm within 15 s of the onset of mating (Crystal, 1967). In contrast, sperm transfer in M. autumnalis occurs in 4 min (Lodha et al., 1970). 25), they rarely achieved genital alignment and almost never initiated a copulation attempt. A species-specific profile of cuticular hydrocarbons might also function, in part, as a reproductive isdating mechanism (Blomquist et a/., 1987). 7. COMPARATIVE EFFECTS OF AGE AND OVARIAN DEVELOPMENT ON CUTICULAR COMPOUNDS AND EVIDENCE FOR A FEMALE PHEROMONE-MEDIATED COPULATORY RESPONSE IN MALES. 7.1 INTRODUCTION Courtship signals play an important role in epigamic recognition and the initiation and maintenance of sexual behaviour, especially among highly mobile and short lived insect species where competition for mates is especially intense Fornhill & Alcock, 1983). Of the four modalities available for sexual signalling and perception (i.e. visual, tactile, acoustic, and Ch~~mosensory),distinctive sensory requirrnents have been identified in only a few genera among the Diptera, and the predominance of any particular moddrty is difficult to establish (Fletcher, 1977; BU~,1981 ; Ewing, 1984). Among cyclorraphous Diptera, several cuticular hydrocarbon pheromones have been identified that mediate: aggregation of both sexes, stimulation of male courtship behaviour on contact or at close range, and recognition of species (Carlson et a/., 1971 ; Muhammed et a/., 1975; Uebel et d., 1975, 1977; Mackley et a/., 1981, Howard & Blomquist, 1982; Jailon, 1984; Blomquist et a/., 1987, 1993; Ma~er Mclaughlin, 1991). Few data, however, are available on chemosensory Signals or other modalities which affect mating behaviour in the Anthomyiidae (Swailes, 1971; Degheele & Hertvedlt, 1974). The objectives of this study were to examine the relative importance of chemosensory, visual, and acoustic cues on mate-finding and mating behaviour in 0.antiqua through laboratory experiments designed to: 1) quantify the relative close-range attractiveness of conspecifics to aduk male and female D. entiqua; 2) evaluate the effect of excision of funciles or aristae and visual sensory deprivation on insemination; 3) collect adutt volatiles and compare differences kween the sexes in relative composition; 4) examine quantitative effects of sex, age, and diet Wt the profile of cuticular compounds; and 5) determine the role of cuticular extracts from mature, virgin females as male mating stimulants. 7.2 METHODS AND MATERIALS Experimenta/ Insects. ~du~D. antiqua for all experiments were produced and maintained as described in Chapter 4. WiM Tunnel ~ioassays.Eight experiments (Table 11, Exp. 1-~)~were conducted in a wind tunnel (Chwter 6) to examine the upwind response of fnde Or female D. antiqua to caged Sexualb mature, virgin males or females were housed within cylindrical screened cages (8.5 cm OD by 11.5 cm long). Virgin males and females, aged 10-14 d were released into the tunnel in grwps of -1 00 for 2 or 6 h from 8 h after the start of the photophase. Response to treatment or 2 Objectives and summark of experimentalset up, including number of replicates for all experiments are given in Table 1 1. assigned to left and right ports after each test, and flies were only used once. All experiments were conducted in an otfactometer room at 23•‹C * 2•‹C. Extmctjan and /\na/vSis of volatile Compounds. To examine the possibility that sex-specifi~ volatile compounds are produced by D. antiqua, 7-d-old aduls of each sex (n = 100) were removed from cu#ure, starved for 12 h, and then males and females Were placed in separate verti~dty-~ri~~t~d5 1, 15 cm (OD) glass aeration chambers (Pierce et a/., 1984). Humidified, Charcod-filtered air wsdrawn at 12 1 per min through the chambers and attached glass traps (- 200 mm x 14 mm OD) containing Porapak Q for 1 wk. These aerations were done at 25'C t 2•‹C under a 16:8 L:D photoperiod (- 540 lux), and each chamber was supplied with five sucrase cubes (n .5) and distilled water dispensed by a sterilized dental-cotton roll. Volatiles were Cross-reference Exp. No. Objective Experimental Design to Results 9,10 To compare the effects of partial male and female Removal of none, one, or both antenna1 funicles from males Fig. 27, antennaectomy and illumination on insemination and females, single pairing of both sexes in 750 ml arenas text for 16 h under illumination (Exp. 9) or in darkness (Exp. lo), folbwed by examination of sperrnathecae for spermatozoa. For each treatment n = 20. 11 To examine the effect of partial female antennaectomy As in Exp. 9 and 10, but with normal males given a choice text on male mating preference mating with intact females or females with the funicles removed, n= 20. 12 To compare the effects of male and female Removal of both aristae from males and females, single text ariitaectomy on insemination. pairing of both sexes in 750 ml arenas with control males or females for 16 h under illumination, followed by examination of spermathecae for spermatozoa. For each treatment n = 40. 7.3 RESULTS Effect of ~em~~dof Funicles or Aristae on Insemination. In comparison with intact controls, signficantb fewer (p when both funicles were removed (Fig. 27). Mating by sham-operated f~rfdesOr males (one fun~~eremoved) was not significantb different from that by intad controls. NO mating occurred at all in hedark in Ewe 10, In frm-choice mating bioassays (Exp. 11). 50% of males mated with both the intact co,,trd female and the female with funicles removed. However, 40% of males mated only with the contrd female, and the other 10% of the males did not mate. In Exp. 12 (Fig. 27), removal of the arista from females, but not males caused significantly fewer females to Chromatograms of the cuticular was!! extracts from adult male (Fig. 28) and female (Fig. 29) 0.antiqua indicated that both sexes shared 34 recognizable peaks; nearly 60% of the occurred between the retention times of the nalkanes standards pentacosane and heptmosane (~25and ~27,respectively). Newfy eclosed miles and females had nearly identical cuticular composition (Fig. 28, 29). Although diet had no apparent effect on quantitative and qualitative composition of cuticular compounds in 10-d-old males (Fig. 28), dramatic changes occurred in females with respect to age and diet (Fig. 29). The major cuticular component of 10-d-old gravid females fed the normal protein-rich diet (compound 2, retention time = 44.1 min) was detected in low amounts in previtellogenic females aged 0 and 10 d, and Was not found in any male extracts. With two exceptions, the percent composition of major cuticular compounds was not significantfy different between fnales and females within each age and diet category (Gtest, ~0.05).One unknown compound (retention time = 44.9 min) was in Significantly higher in 1 males fed a protein-rich diet than in similarly aged and fed gravid females (0. 8.6, P Male Female Exp. 9 Exp. 12 ------Control I ------Control ---___ a One Funicle Both Funicles Aristae Excised Excised Excised (Sham-operated) Newly-eclosed males Tenday~ldmales fed normal protein-rich diet SOoC/So~/min 1 min Tenday~ldmales led sucrose only TIME (min) Newly-eclosed females Tenday-old females fed normal prolein-rich diet 500~/5~~/rnin 1 min Tenday-old females fed sucrose only TIME (rnin) Extract of gravid, 10-d-old female Solvent control -t L 120 a, 40 20 a > 100 0 C 30 3 80 0- LLa, 60 20 10 ui 40 c/j 10 + 20 Ca a, 0 0 0 Genital Copulation 2 Substrate Aerial Substrate Aerial Inspection Contact alignment attempts Courtship Behaviour 7.4 DISCUSSION Feeding only on sucrose by adult males had no significant effects on the proportion of gr~vid fernel% inseminated, magnitude of oviposition response and total numbers of eggs deposited in 1:1 or 1:10 mde:female matchings over 2 d, when compared with the response of males Provided control diet containing protein and carbohydrate Males maintained on sucrose or diet for 10 d mated an average of 5.2 and 4.3 females, respe~tkely,over a 24 h and gravid femalesmated with elher sucrose-fed Or control males dewled 265% of total available eggs. 9. LITERATURE CITED Allen, W. R. & W L Askew. 1970. A simple technique for mass-rearing the onion maggot @i~tera:~n~~~~~~~~~~) on an a*ficial diet. Can. Ent. 102: 15s1558. Anderson, J. R. 1978. Mating behavior of Stomovs ca/citrans effects of a blood meal on the as mating drive of males and its a prerequisite for proper insemination of females, J. EntOrnd. 71 : 379-386. Baker, T. C. & R. T. ard& 1984. Techniques for behavioral bioassays, PP. 45-73. In: H. E. hum me^ & T. A. Miller (eds.), Techniques in pheromone Research. Springer-Verlag, New York, N. Y. C. M. van Gemen & L A. bwrrnce. 1976. Relationship Bmwne, L., R. J. ~~~1~11, beken pmein ingedionand sexual receptivity in females of the Australian Sheep blowfly, Cynia. Physiol. Ent. 5: 1 -6. Blomqulst, G. J., J. A Tlllman-Wall, L. Guo, D. R. Qulllcl, P. Gu & C. Schal. 1993. Hydrocarbon and hydrocarbon derived sex pheromone in insects: biochemistry and endocrine regulation. pp. 317-351, In: D. W. Stanley-Samuelson 8I D. R. Nelson (eds.). Insect Lipids: Chemistry, Biochemistry and Biology. University of Nebraska Press, Lincoln, Nb. Blum, M. S. 1974. Pheromonal bases of social manifestations in insects. pp. 190-199, In: M.C. Birch (ed.) . Pherornones, North Holland Research Monographs, Amsterdam, Net h . Bol, A 1972. Paringsgedrag van de uienvlieg. Doctoraal verslag biologie, RJksuniversiteit, Leiden, Neth., 48 pp. Bolvln, G. & D. L. Benott. 1987. Predicting onion maggot (Diptera: Anthomyiidae) flights in southwestern Quebec using degree-days and common weeds. Phytoprotection 68: 65-70. Brlthh Columbla Mlnhtry of Agdcutture and Flsherles, 1991. Vegetable production guide 1991. No. 635-0971 1, Ministry Agric. 8 Fish. Prov. of B. C.,Victoria. B. C. Broersma, D. B. & W. L. Luckmann. 1968. Frequency of mating by the female onion maggot adult. J. Ewn. Entomol. 61: 568. Bulmer, M. G. 1983. Models for the evolution of protandry in insects. Theor. Popul. Bio/. 23: 3 14-322. Burk, T. E. 1981. Signalling and sex in acalyptrate flies. Fla. Entomol. 64: 30-43. Carlson, D. A., M. S. Mayer, D. L. Sllhacek, J. D. James, M. Beroza & B. A. Blerl. 1971. Sex attractant pheromone of the house fly: isolation, identification and synthesis. Science, 174: 76- 78. Carruthers, R. I., D. L. Haynes & D. M. Macleod. 1985. Entomophthora muscae (Enthomophthorales: Entomophthoracae) mycosis in the onion fly, Delia antiqua (Diptera: Anthomy iidae) . J. Invert. Pathd. 45: 81 -93. Chaudhury, M. F. B. & H. J. Ball. 1973. The effect of age, nutritional factors, and gonadal development on the mating behaviour of the face fly, hfusca autumnalis. J. Insect Physjol. 19: 57-64. Chapman, R. F. 1982. The insects, structure and function. Harvard Univ. Press, Cambridge, Mass. Chen, P. S. 1984. The functional morphology and biochemistry of insect male accessory glands and their secretions. Annu. Rev. Entomol. 29: 233-255. Coaker, T. H. & S. Flnch. 1972. The association of the cabbage rootfly with its food and host plants. pp. 119-128, In: H. F. van Emden (ed.). InsectlPlant Relationships, Vol. 6, Symposia of the Royal Entomol. Soc. London, London, U. K. Colwell, A. E. & H. H. Shorey. 1975. The courtship behavior of the house fly, Musca domestics (Diptera: Muscidae) . Ann. Entomol. Soc. her.68: 152-1 56. Colwell, A E. & H. H. Shorey. 1977. Female-produced stimuli influencing courtship of male house flies (Musca domestica). Ann. Entomd. Soc. her.,70: 303-308. Cowles, R. S., J. E. Keller & J. R. Mllier. 1989. Pungent spices, ground red pepper, and synthetic capsaicin as onion fly ovipostional deterrents. J. Chem. Ecol. 15: 719-730. Cowles, R. S., J. R. Mlller, R. M. Holllngworth, M. T. Abdeljtal, F. Szurdokl, K. Bauer & G. Matolcsy. 1990. Cinnamyl derivatives and monoterpenoids as nonspecific ovipositional deterrents of the onion fly. J. Chem. Ecol. 16: 2401- 2428. Craddock, E. M. & C. R. B. Boake. 1992. Onset of vitellogenesis in female Drosophila si/vesb.is is accelerated in the presence of sexually mature males. J. Insect Physiol., 38: 643-650. Crystal, M. M. 1967. Reproductive behavior of laboratory-reared screw-worm flies (Diptera: Calliphoridae). J. Med. Ent., 4: 443-450. Dadd, R. H. 1985. Nutrition: organisms. pp. 313-389, In: G. A. Kerkut & L. I. Gilbert (eds.). Comprehensive Insect Physiology, Biochemistry and Pharmacology, Vol. 4, Pergamon Press, Oxford, U. K. Davleq N. B. 1978. Territorial defence in the speckled wood butterfly (Pararge aegeria); the resident always wins. him. Behv. 26: 138-147. Degheele, D. & L. Hemeldt. 1974. Anatomical and histological study of the cabbage root fly Hylemya brassicae rectum on the occurrence of a pheromone gland. Mededel. Facult. Landbouwweten. RJksuniversiteit, Gent, 39, 1394 1 398. Dethler, V. G. 1961. Behavioral aspects of protein ingestion by the blowfly Phormia regha (Meigen) . Biol. Bull. 121: 456-470. Dethler, V. G. 1982. Mechanisms of host-plant recognition. Entomol. Exp. Appl. 31 : 49-56. Dethler, V. G., L. B. Browne & C. N. Smith. 1960. The designation of chemicals in terms of the responses they elicit from insects. J. Econ. Entomol. 53: 134-1 36. Dindonis, L. L. & J. R. Mlller. 19808. Host-finding responses of onion and seedcorn flies to healthy and decomposing onions and several synthetic constituents of onion. Environ. Entorno/. 9: 467-472. Dlndonls, L. L. & J. R. Mlller. 1980b. Host-finding behavior of onion flies, Hylemya antiqua. Environ. Entomd. 9: 769-772. Dlndonls, L. L. & J. R. Mlller. 1981. Onion fly trap catch as affected by release rates of n- dipropyl disulfide from polyethylene enclosures. J. Chem. Ecol. 7: 41 1-418. Down-, J. A. 1969. The swarming and mating flight of Diptera. Annu. Rev. Entomol., 14: 271- 298. Eckenrode, C. J. 1988. Delia antiqua (Meigen): an increasing threat in FIorth America. Acta Hart. 21 9: 27-30. Eckenrode, C. J. & J. P. Nyrop. 1986. Impact of physical injury and commercial lifting on damage to onion bulbs by larvae of onion maggot (Diptera: Anthomyiidae). J. Ewn. Entorno/. 79: 1606-1608. Eckenrode, C. J., E. V. Vea & K. W. Stone. 1975. Population trends of onion maggots correlated with thermal unit accumulations. Environ. Entomol. 4: 785-789. Elllngton, J. J. 1963. Field and laboratory observations on the life history of the onion maggot Hylemyia antiqua(Meigen) . Ph. D. dissertation, Cornell University, lthaca. EIlls, P. R., C. J. Eckenrode & G. E. Harman. 1979. Influence of onion cultivars and their microbial colonizers on resistance to onion maggot. J. Econ. Entomol. 72: 51 2-515. Eymann, M. & W. G. Frlend. 1983. Onion maggot development in a bacteria-rich environment without onion tissue. Proc. Entomd. Soc. Ont. 11 4: 99-100. Eymann, M. & W. G. Frlend. 1985. Development of onion maggots (Diptera: Anthomyiidae) on bacteria-free onion agar supplemented with vitamins and amino acids. Ann. Entomol. Soc. Amer. 78: 182-185. Ewing, A. W. 1984. Acoustic signals in insect sexual behaviour. pp. 223-240, In: T. Lewis (ed.). Insect Communication. Academic Press, London, U. K. Fagerstrem T. & C. Wlklund. 1982. Why do males emerge before females? Protandry as a mating strategy in male and female butterflies. Oecologia 52: 164166 Flnch, S., 1971. The fecundity of the cabbage root fly Erioischia brassicae under field conditions. Ent. Exp. Appl. 14: 147-160. Flnch, S. 1986. Assessing host-plant finding by insects. pp. 23-63, In: J. R. Miller 81 T. A. Miller (eds.) . Insect-plant Interactions, Springer-Verlag, New York, N.Y. Flnch, S. 1989. Ecological considerations in the management of Delia pest species in vegetable crops. Annu. Rev. Entomol. 34: 11 7- 137. Flnch, S. & R. H. Colller. 1983. Emergence of flies from overwintering populations of cabbage root fly pupae. Ed. Entomol. 8: 29-36. Flnch S. & C. J. Eckenrode. 1985. Influence of unharvested, cull-pile, and volunteer onions on populations of onion maggot (Diptera: Anthomyiidae). J. Econ. Entomol. 78: 542-546. Flnch, S., C. J. Eckenrode & M. E. Cadow. 1986. Behavior of onion maggot (Diptera: Anthmyiidae) in commercial onion fields treated regularly with parathion sprays. J. Econ. Entomol. 79: 107- 11 3. Flnch, S. & G. Sklnner. 1982. Upwind flight by the cabbage root fly, Delia radicum. Physjol. Entomd. 7: 387-399. Fltzpatrlck, S. M. & W. G. Welllngton. 1982. Insect territoriality. Can. J. 2001.61: 471-486, Fletcher, B. S. 1977. Behavioral responses of Diptera to pheromones, allomones, and kairomones. pp. 129148, In: H. H. Shorey & J. J. McKekey Jr. (eds.). Chemical Control of Insect Behavior: Theory and Application, Wjley-Interscience, New York, N.Y. Foster, W. 1967. Hormone-mediated nutritional control of sexual behavior in male dung flies. Science, 158: 1596-1597. Gheraslm, V. & M. Lacatusu. 1977. Aphaereta minuta (Nees) (Hymenoptera-Braconidae), principalul factor limitativ al populatiilor de diptere daunatoare culturilor de ceapa din R.S. Romania. Anal. Instit. Cerc. Protect. Plant. 1 2: 229-236. Golub, M. A. & I. Weatherston. 1984. Techniques for extracting and collecting sex pheromones from live insects and from artificial sources. pp. 224285, In: H. E. Hummel & T. A. Miller (eds.). Techniques in Pheromone Research, Springer Vedag, New York, N. Y. Gray, H. E. 1924. The onion maggot in Alberta. Report Entomd. Soc. Ont, for 1923, 54: 36-38. Grlfftths, G. C. D. 1982. Flies of the Nearctic region. Cyclorrphapha II (Schizophora: Calyptratae) Anthomyiidae. Volume VIII, Part 2, NO. I., E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart . Hammack, L. 1986. Pheromone-mediated copulatory responses of the screwworm fly, Cochliomyia hominivorax. J. Chem. Ecol. 1 2:1 623-1 631 . Happ, G. M. 1992. Maturation of the male reproductive system and its endocrine regulation. Annu. Rev. Entomol. 37: 303-320. Hanls, C. R., J. H. Tolman & H. J. Svec. 1982. Onion maggot (Diptera: Anthomyiidae) resistance to some insecticides following selection with parathion or carbofuran. Can. Ent. 114: 68 1 -685. Harrk, M. 0. & J. R. Mlller. 1988. Host-acceptance behaviour in an herbivorous fly, Delia antiqua. J . Insect Physiol. 34: 1 79- 1 90. Hawk-, C. 1973. Factors affecting the aggregation of the adult cabbage root fly (Erioischia bras~icae(Bouche)) at hedges. J. Appl. Ecol., 1 0: 695-703. Hawk-, C., Patton, S. & T. H. Coaker. 1978. Mechanisms of host plant finding in adult cabbage rod fly, Delia brassicae. Entomol. Exp. Appl., 24: 21 9-227. Hawk-, C. & T. H. Coaker. 1979. Factors affecting the behavioural responses of the adult cabbage rod fly, Delia brassicae, to host plant dour. Entomol. Exp. Appl. 25: 45-58. Hlgley, L. G. & L. P. Pedlgo. 1984. Seedcorn maggot (Di~tera:Anthomyiidae) reproductive biology and techniques for examining ovarian dynamics. J. Econ. Entomol. 77: 1 149-1153. HIII, D. S. 1987. Agricultural insect pests of temperate regions and their control. Cambridge University Press, Cambridge, England. Honda, I., Y. khlkawa & Y. Matsumoto. 1983. Morphological studies on he antennd sensilla of the onion fly, Hylemya antiqua Meigen (Diptera: Anthomyiidae). Appl. Entomol. Zool. 18: 170- 181. Honda, I., Y. Ishlkawa & Y. Matsumoto. 1987. Electrophysiological studies on the antenna1 olfactory cells of the onion fly, Hylemya antiqua Meigen (Diptera: Anthomyiidae). Appl. Entomol. Zod. 22: 417-423. Hough-Goldstein, J. A,Hess, K. A. & S. M. Gates. 1987. Group effect on seedcorn maggot (Diptera: Anthomyiidae) mating behavior. Ann. Entomol. Sac. Amer. 80: 520-523. Huyton, P. M. & P. A. Langley. 1982. Copulatory behaviour of tsetse flies Glossinia morsitans and G. austeni. Physiol. Entomd. 7: 167-1 74. Ikeshojl, T., Y. lshlkawa & Y. Matsumoto. 1980. Attractants against the onion maggots and flies, Hylemye antiqua, in onions inoculated with bacteria. J. Pest. Sci. 5: 343350. IkeshoJl,T., y. lshikawa & Y. Matsumoto. 1981. Ecological and chemical interactions between onion and onion maggot, Hylemya antiqua (Diptera: Anthomyiidae). Rev. Plant Protec. Res. 14: 141-1 48. Ishlkawa, Y., Y. Matsumoto, M. Tsutsuml & Y. Mltsul. 1984. Experimental field trapping of the onion and seed-corn flies, Hylemya antiqua and H. plafura (Diptera: Anthomyiidae), using 2- phenylethanol for population estimation. Appl. Entomol. Zool. 19: 75-81 Ishlkawa, Y., S. Tsukada & Y. Matsumoto. 1987. Effect of temperature on the larval development and divause induction in the onion fly, Hylemya antiqua Meigen (Diptera: Anthomyiidae). Appl. Entomol. Zool. 22: 610-61 6. Jallon, J. 1984. A few chemical words exchanged by Drosophila during courtship and mating. Behavior Genetics, 14: 441 -478. Javer, A, A. D. Wynne, J. H. Borden & G. J. R. Judd. 1987. Pine oil: an oviposition deterrent for the onion maggot, Delia antiqua (Meigen) (Diptera: Anthomyiidae). Can. Ent. 119: 605-609. Jones, C. J., D. E. Mllne, R. S. Patterson, E. T. Schrelber & J. A. Millo. 1992. Nectar feeding by Stomoxys calcitrms (Diptera: Muscidae): effects on reproduction and survival. Envjron. Entomd. 21 : 141 - 147. Jones, M. G. 1971. Observations on changes in the female reproductive system of the wheat bulb fly Leptohylemyia coarctata (Fall.). Bull. Entomol. Res. 61, 55-68. Judd, G. J. R. & J. H. Borden. 1988. Long-range host-finding behaviour of the onion fly Delia antiqua (Diptera: Anthomyiidae): ecological and physiological constraints. J. Appl. Ecol. 25: 829- 845. Judd, G. J. R. & J. H. Borden. 1989. Distant 0Nactory response of the onion fly, Delia antiqua, to host-plant odour in the field. Physiol. Entomol. 14: 429-441. Judd, G. J. R. & J. H. Borden. 1992a. Aggregated oviposition in Delia antiqua (Meigen): a case for mediation by semiochemicals. J. Chem. Ecol. 18: 621 -635. Judd, G. J. R. & J. H. Borden. 1992b. Influence of different habitats and mating on otfactory behavior of onion flies seeking ovipositional hosts. J. Chem. Ecol. 18: 605-620. Kcmtal, V. 1993. Oogenesis and oviposlion in the cabbage root fly, Delia radicum (Diptera: Anthornyiidae), influenced by food quality, mating and host plant availability. Euro. J. Entorno/. 90: 137-147. Krebs, C. J., 1989. Ecological methodology. Harper Collins, New York, N.Y. Leopold, R. A. 1976. The role of male accessory glands in insect reproduction. Annu. Rev. Entomol. 21 : 199-221 . Lllmatainen, J., A Holkkala, J. Asp1 & P. Welbergen. 1992. Courtship in Drosophila montana: the effects of male auditory signals on the behaviour of flies. him. Behav. 43: 3548. Uss, W. J., L. J. Cut, P. H. Westlgard & C. E. Warren. 1986. Perspectives on arthropod community structure, organization, and development in agricuhural crops. Annu. Rev. Ent&. 31 : 455478. Liu, H. J., McEwen, F. L. & G. Rltcey. 1982. Forecasting events in the life cycle of the onion maggot, Hylemya antiqua (Diptera: Anthomyiidae): application to control schemes. Environ. Entomol. 11 : 751-755. Lodha, K. R., R. E. Treece & F. R. Koutz 1970. Studies on the mating behavior of the face fly. J. Econ. Entomol. 63: 207-212. Loosjes, M. 1976. Ecology and genetic control of the onion fly, Delia antiqua (Meigen). Agricult. Res. Report, 857, ~udoc,Wageningen, 179 pp. Mackerras, M. J. 1933. Observations on the life-histories, nutritional requirements and fecundity of blowflies. Bull. Entomol. Res. 24: 353-362. Martin, J. S. 1981. Mating behaviour of the onion maggot fly Hylemya antiqua Meigen in laboratory conditions. M. Sc. thesis, Univ. Guelph, Guelph, Ontario, 43 pp. Martin J.S. & F. L. McEwen. 1982. Frequency of mating in the onion maggot, Hylemya antiqua (Diptera: Anthomyiidae). Can. Ent 114: 647-648 Martlnson, T. E., J. P. Nyrop, & C. J. Eckenrode. 1989. Long-range host-finding behavior and colonization of onion fields by Delia antiqua (Diptera: Anthomyiidae). J. Econ. Entomol. 82: 11 1 1 - 1120. Maburnoto, Y. & A. J. Thoroteinson. 1968a. Otfadory response of larvae of the onion maggot, Hylemya antiqua Meigen (Diptera: Anthomyiidae) to organic sutfur compounds. Appl. Entorno/. Zod. 3: 107-111. Maburnoto, Y. & A. J. Thomtelnson. 1968b. Effect of organic sutfur compounds on oviposition in onion maggd, Wlemya antiqua Meigen (Diptera: Anthomyiidae). Appl. Entomol. Zoo/. 3: 5-12. Mayer, M. S. & J. R. Mchughlln. 1991. Handbook of insect pheromones and sex attractants. CRC Press, Boca Raton, Fla. Mclachlan, A. J. & D. F. Allen. 1987. Male mating success in Diptera: advantages of small size. Oikos 48: 11 - 14. McW, D. G. R. 1964. Nutrition and feeding behavior of the adutt onion maggot, Hylemya antiqua. J. Ewn. Entomol. 57: 845-847. Meola, R. W., R. L. Hanls, S. M. Meola, & D. D. Oehler. 1977. Dietary-induced secretion of a sex pheromone and development of sexual behavior in the stable fly. Environ. Entorno/. 6: 895- 897. Mlles, M. 1953. Studies of British anthomyiid flies. V. The onion fly, Delia antiqua (Mg.). Bull. Entomol. Res. 44: 583-588. Miles, M. 1955. Studies of British anthomyiid flies. VII. The onion-fly complex. Bull. Entomd. Rw. 46: 21-26. Mlles, M. 1958. Studies of British anthomyiid flies. IX. Biology of the onion fly, Delia antiqua (Mg .) . Bull. Entomd. Res. 49: 405-41 4. Mlller, J. R. & R. S. Cowles. 1991. Stimulo-deterrent diversion: a concept and its possible application to onion maggot control. J. Chem. Ecol. 16: 3197-3212. Mlller, J. R. & B. K. Haarer. 1981. Yeast and corn hydrolysates and other nutritious materids as attractants for onion and seed flies. J. Chem. Ecol. 7: 555-562. Mlller, J. R., M. 0. Harrb & J. A. Breznak. 1984. Search for potent attractants of onion flies. J. Chem. Ecol. 10: 1477- 1488. Mlller, J. R. & K. L. Strlckler. 1984. Finding and accepting host plants, pp. 127-157, ~n:W. J. Bell & R. T. Carde (eds.). Chemical Ecology of Insects. Sinauer Assoc. Sunderland, Mass. Miller, L. A & R. J. McClanahan. 1960. Life-history of the seed-com maggot, Hylemya cilicrura (Rond.) and of H. ljmrata (Mg.) (Diptera: Anthomyiidae) in southwestern Ontario. Can. Ent., 92: 210-221. Mlssonnler, J. & M. Stengel. 1966. Etude des facteurs de fecondite des aduttes de Chortophila brasshe B., Hy/emp antiqua Meig. et Pegomyia betae Curt. Ann. Epiphyties 17: 541. Morgan, p. 6. 1973. Effect of aging and p~pulationdensity on wing fragmentation in house flies. J. Em. Entomd. 66: 993995. Morrison, P. E., K. Venkatesh, & 6. Thompson. 1982. The role of male accessory-gland substance on female reproduction with some obsmations of spermatogenesis in the stable fly. J. Ins& Physiol. 28: 607-614. Muhammed, S., J. F. Butler & D. A. Carison. 1975. Stable fly sex attractant and mating pheromones found in female body hydrocarbons. J. Chem. Ecol. 1: 387-398. Murvosh, C. M., R. L. Fyo & G. C. LaBrecque. 1964. Studies on the mating behavior of the house fly, Musca domestics L. Ohio J. Sci., 64: 264271 . Nlemczyk, H. D. 1964. Mass rearing of the onion maggot, Hylemya antiqua, under laboratory conditions. J. Em.Entomd. 57: 57-60. Nlemezyk, H. D., 1965. The response of Hylemya antiqua adults to hydrolized proteins and other materials: a laboratory study. J. Ecm. Entomol. 58: 425428. Noordlnk, J. p. W. 1971. Irradiation, competitiveness and the use of radioisotopes in sterile- male studies with the onion fly, Hylemya antiqua (Meigen). pp. 323-328, In: Sterility Principle for Insect Control or Eradication, IAEA-SM-138162, International Atomic Energy Agency, Vienna, Aust. Nottingham, S. F. & T. H. Coaker. 1985. The olfactory response of cabbage root fly, Delia radicum, to the host plant volatile allylisothiocyanate. Ent. Exp. Appl. 39: 307-316. Nottingham, S. F. & T. H. Coaker. 1987. Changes in flight track angles of cabbage rod fly, DeIL radicum, in diffuse clouds and discrete plumes of the host plant volatile allylisothi~cyanat~. EnL Exp. Appl. 43: 275278. Nottlngham, S. F. 1988. Host-plant finding for oviposition by adult cabbage root fly, Delia radicum. J. lnsed Physiol. 34: 227-234. Nylln, S., C. Wiklund, P-0. Wlckman & E. Garcla-Barros. 1993. Absence of trade-offs between sexual size dimorphism and early male emergence in a butterfly. Ecology 74: 1414 1427. Oldroyd, H. 1964. The natural history of flies. Weidenfield & Nicholson, London, U. K. Otronen, M. 1990. Mating behavior and sperm competition in the fly, Dryomyza anilis. Behv. Ecol. Sociobiol. 26: 349-356. Parker, G. A 1968. The sexual behaviour of the bloay, Protophonnia terrae-novae R.-D. Behaviour, 32: 29 1-308. Parker, G. A 1970. The reproductive behaviour and the nature of sexual selection in Swtophe~aster~ah L. (Diptera: Scatophagidae). VII. The origin and evolution of the passive phase. Evolution, 24: 774788. Parker, G. A 1978. Evolution of competitive mate searching. Annu. Rev. Entomol. 23: 173-196. Perron, J. P. & J. LaFrance. 1961. Notes On the life-history of the onion maggot, Hy/emya antiqua (Meig.) (Diptera: Anthomyiidae) reared in field cages. Can. Ent. 93: 101-1 06. Petem, T. M. & P. Barbosa. 1977. Influence of population on size, fecundity and developmental rate of insects in cutture. Annu. Rev. Entomol. 22: 431 -450. Phelen, P. L. 1992. Evolution of sex pheromones and the role of asymmetric tracking. pp. 265- 314, In: B. D. Roitberg & M. B. lsman (eds.). hect Chemical Ecology, an Evolutionary Approach. Chapman & Hall, New York, N. Y. Pierce, H. D. Jr., A. M. Plerce, J. G. Millar, J. W. Wong, V. G. Verlgln, A. C. Oehlschlager and J. H. Borden. 1984. Methodology for isolation and anasis of aggregation pheromones in the genera Crypolestes and Oryzaephilis (Coleoptera; Cucujidae), pp. 121-1 37, In: Proc. Ill Int. Working Conf. on Stored Product Entomol., Kansas State Univ., Manhattan, Kansas. Price, J. L. 1974. Studies on the mating behaviour of the cabbage root fly Erioischia brasicae (8ouche). Ph. D. dissertation, Univ. Birmingham, U. K. Prke, J. L. 1977. Morphology and abnormalities of the reproductive organs of the cabbage root fly, Delia brassicae (Wiedemann) (Diptera: Anthomy iidae) . Bull. Entomol. Res. 67: 459-470, Prokopy, R. J. 1986. Visual and olfactory stimulus interaction in resource finding by insects, pp. 80-89, In: T. L. Payne, M .C. Birch & C. E. J. Kennedy (eds.), Mechanisms in Insect Olfaction. Clarendon Press, Oxford, U. K. Raabe, M. 1986. Insect reproduction: regulation of successive steps. Advan. Invert.Repr. 3: 163- 176. Ralkhel, A. S. & T. S. Dhadlalla. 1992. Accumulation of yolk proteins in insect wcytes. Annu, Rev. Entomol. 37: 2 17-251 . Reltz, S. R. & p. H. Adler. 1991. Courtship'and mating behavior of Eucelatoria bryani (Diptera: Tachinidae) , a larval parasitoid of Heliothis species (Lepidoptera: Noctuidae) . Ann. Entomol. sot. Amer. 84: 111-117. Robinson, A. S. 1980. Effect of sex ratio at three densities on reproduction in laboratory colonies of Delia (= Hylemya) antiqua Meig. Zeit. ang. Entomol. 90: 82-89. Roblnson, A S., M. Herfst & L. Vosselman. 1980. Genetic control of Delia antiqua (Meigen) (Diptera: Anthmyidae). Sensitivity to diapause interfering with a field-cage experiment using a homozygous chrmosomal translocation. Bull. Entomol. Res. 70: 103-1 11 . Robinson, A S. & G. Zurllnl. 1979. The response of two strains of Hylemya antiqua (Diptera: Anthomyiidae) to a constant and alternating temperature regime. Can. Ent. 111 : 1207-1217. Roblnson, A S. & G. Zurllnl. 1981. Mating success of differently sized onion flies, Delia antiqua. Entomd. &p. Appl. 30: 101 - 105. Sabells, M. W. & P. Schlppers. 1984. Variable wind direction and anemotactic strategies of searching for an odour plume. Oecologia, 63: 225-228. SAS Institute Inc. 1988. SASJSTAT User's Guide. Release 6.03 Edition. SAS Institute Inc. Gary, N.C. Scott, D. R. 1969. A selected bibliography of the onion maggd, Hylemya antiqua (Meigen). Bull. Entomol. Soc. her.15: 345-354. Schnelder, W. D., J. R. Miller, J. A Breznak & J. F. Fob-. 1983. Onion maggot, Delia antiqua, survival and development on onions in the Presence and absence of microorganisms. Entmol. Eip. Appl. 33: 50-56. Shorey, H. H. 1973. Behavioral responses to insect pheromones. Annu. Rev. Entomol. 18: 349- 380. Shorey, H. H. 1977. Interaction of insects with ther chemical environment. pp. 1-5, In: H.H. Shorey & J. J. McKelvey, Jr. (eds.). Chemical Control of Insect Behavior: Theory and Application, Wiley-Interscience,New York, N. Y. Sllversteln, R. M., J. 0. Rodln & D. I. Wood. 1967. Methodology for isolation and identification of insect pheromones with reference to studies on California five-spinned Ips. J. Econ. Entorno/. 60: 944949. Slnger, M. C. 1982. Sexual selection for small size in male butterflies. Am. Nat. 119: 440-443. Spencer, J. L., G. 1. Bush, Jr., J. E. Keller, & J. R. Mlller. 1992. Modification of female onion fly, Delia antiqua (Meigen), reproductive behavior by male paragonid gland extracts (Diptera: Anthornyiidae) . J. Insect Behv. 5: 689-697. Stoffolano, J. G. Jr. 1974. Influence of diapause and diet on the development of the gonads and accessory reproductive glands of the black blowfly, Phormia regina (Meigen). Can. J. Zoo/. 52: 981-988. Strangways-Dlxon, J. 1961. The relationship between nutrition, hormones and reproduction in the blowfb Calliphora erythrocephala (Meig.). I. Selective feeding in relation to the reproductive cycle, the corpus dhtum volume and fertilization. J. Exp. Biol. 38: 225-235. Swalles, G. E. 1961. Laboratory studies on mating and 0viposition of Hylemya brassicae (Bouche) (Diptera: Anthomyiidae). Can. Ent. 93: 940-943. Swalles, G. E. 1971. Reproductive behaviour and effects of the male accessory gland substance in the cabbage maggot, Hylemya brassicae. Ann. Entomol. SOC.her. 64: 176-1 79. Theunlssen, J. 1973. Egg chamber development in the onion fly, Hylemya antiqua (Meigen) (Diptera: Anthomyiidae). Int. J. insect Morphol. Embvol. 2: 87-99. Theunlssen, J. 1974. Effects of temperature on egg-chamber development development in the onion fly, Hylemya antiqua (Meigen) (Diptera: Anthomyiidae). Ent. Exp. Appl. 17: 355-366. TheunIssen, J. A. M. B. 1976. Aspeds of gametogenesi and radiation pathology in the onion fly, Hylemya antiqua (Meigen) . I. Gametogenesis. Meded. -andbouwhogech. Wageningen, 76: 1- 164. Thornhill, R. & J. Alcock. 1983. The evolution of insect mating systems. Harvard Univ. Press, Cambridge, Mass. Throne J. E. & C. J. Eckenrode. 1985. Emergence Patterns of the seedcorn maggot, Delia platura (Diptera: Anthomyiidae). Enitiron. Entomol. 14: 182-186. Ticheler, J. 1969. Bestrijding van voor land- entuinbouwgewassen schaddijke vliegesoorten in het bijzonder de uievlieg, Hylemya antiqua (Meig.), door middel van de 'sterile male' techniek. lnst. Plantenz. Onderzoek, pp. 7981. Ticheler, J. 1971. Rearing of the onion fly, Hylemya antiqua (Meigen), with a view to release of sterilized insects. pp. 341 -346, In: Sterility Principle for Insect Control or Eradication, IAEA-SM- 138/62, International Atomic Energy Agency, Vienna, Aust. Tobln, E. N. & J. G. Stoffohno, Jr. 19730. The courtship of Musca species found in North America. 1. The house fly, Musca domestics. Ann. Entomol. Soc. Arner. 66: 1249-1257. Tobln, E. N. & J. G. Stoffohno, Jr. 1973b. The courtship of Musca species found in North America. 2. The face fly, Musca autumnalis, and a comparision. Ann. Entomol. Soc. Amer., 66: 1329-1334. Tolman, J. H., Whlstlecraft, J. W. & C. R. Harris. 1985. Delia antiqua. pp. 49-57, In: P. Singh & R. F. Moore, (eds.). Handbook of Insect Rearing Vol. 2. Elsevier, Amsterdam, Neth.. Tomlln, A. D., J. J. Mlller, C. R. Harrb & J. H. Tolman. 1985. Arthropod parasitoids and predators of the onion maggot (Diptera: Anthomyiidae) in southwestern Ontario. J. €con. Entomol. 78: 975-981. Treherne, R. C. & M. H. Ruhman. 1920. The onion-maggot. Proc. Entomol. Soc. B. C. 11: 91- 93. Truman, J. W. 1972. Circadian rhythms and physiology with special reference to neuroendocrine processes in insects. pp. 11 1 -1 35, Incircadian Rhythrnicity . Pudoc, Wageningen, Neth. Tsutsuml, M. & Y. Mltsul. 1987. Effects of baits on survival and development of ovary of onion fly (Hylemyia antiqua). Ann. Rept. Plant Prot. N. Japan 38: 146-148. Uebel, E. C., P. E. Sonnet, B. A Bled & R. W. Miller. 1975. Sex pheromone of the stable fly: Isolation and preliminary identification of compounds that induce mating strike behavior. J. Chem. Ed.1 : 377-385. Uebel, E. C., P. E. Sonnet, R. E. Menzer, R. W. Mlller & W. R. LUS~Y.1977. Mating-stimulant pheromone and cuticular lipid constituents of the little house fly, Fannia canicularis. J. Chem. Ed.3: 269-278. van Heemeft c., D. H. Ketel, J. J. F. Muldem & W. J. Van den Brlnk. 1979. Relationship between sex and developmental time in the onion fly Hylemya antiqua (Meigen). Neth. J. zoo/. 29: 233-241. Vernon, R. S., G. J. R. Judd & J. H. Borden. 1987. c~rfmercialmonitoring programme for the onion fly, Deli, entiqua (Meigen) (Diptera: Anthomyiidae) in south-western British Cdumbia. Crop Protect. 6: 304-312. Vernon, R. S., G. J. R. Judd, J. H. Borden, H. 0. Pierce Jr. & A C. Oehlschlager. 1981. Attraction of Hylemya antiqua (Meigen) (Diptera: Anthomyiidae) in the field to host-produced oviposition stimulants and their nonhost analogues. Can. J. Zool. 59: 872-881. Vemon, R. S., H. D. Pierce Jr., J. H. Borden & A. C. Oehlschlager. 1978. Host selection by Hylemya entiqua: identifcation of oviposition stimulants based on proposed active thioalkane moieties. Environ. Entomd. 7: 728-731 . Vogt, W. G., T. L. Woodburn & M. Tyndale-Blscoe. 1974. A method of age determination in Lucilia cuwia (Wied.) (Diptera: Calliphoridae) using cyclic changes in the female reproductive system. Bull. Entomol. Res. 64: 365-370. Wall, R., & p. A bngety. 1993. The mating behaviour of tsetse flies (Glossina): a review. Physid. Entomd 18: 2 11 -21 8. Wang, G-y., M. D. Gmenfleld & T. E. Shelly. 1990. Inter-male competition for high-quality host- plants: the evolution of protandry in a territorial grasshopper. Behav. Ecol. Sociobiol. 27: 191- 198. Wedeli, N. 1992. Protandry and mate assessment in the wartbiter Decticus vermcivorus (Orthoptera: Tettigoniidae). Bshav. Ecol. Sociobiol. 3 1: 301-308. Wlens, M. N., J. E. Rahe, R. S. Vernon & J. A McLean. 1978. Ovipositional deterrents for Hylemya antiqua in hydrated seeds of Phaseolus vulgaris. Environ. Entomol. 7: 165-167. West-Eberhard, M. J. 1984. Sexual selection, competitive communication and species-specific signals in insects. pp. 283-324, In: T. Lewis (ed.). Insect Communication, Academic Press, London. U. K. Weston, P. A., J. E. Keller & J. R. Mlller. 1992. Ovipositional ~timulusdeprivation and its effect on lifetime fecundity of Delia antiqua (Meigen) (Diptera: Anthomy Mae). Environ. Entorno/. 2 1: 560-565. Weston, P. A & J. R. Miller. 1985. Influence of cage design on precision of tube-trap bioassay for attractants of the onion fly, Delia antiqua. J. Chem. Ecd. 11 : 435-440. Whltfleld, G. H., R. I. Carruthers, & D. L. Haynes. 1985. Phenology and control of the onion maggot (Diptwa: Anthomyiidae) in Michigan onion production. Agr. Ecosystems & Environ. 12: 189-200. Wlklund, C. & T. Fagerstrbm. 1977. Why do males emerge before females? A hypothesis to explain the incidence of protandry in butterflies. Oecologia 31 : 153-158. Zar, J. H. 1984. Biostatistical Analysis. 2nd ed. Prentice-Hall, Englewood Cliffs, N. J. Zurlini G. & A. S. Robinson. 1978. Genetic control of Hylemya antiqua Ill. Differences in pupation ability between two strains. Popul. Ecol. 20: 1-14. Zurlini, G. & A. S. Robinson. 1980. The effect of crowding on adult populations of Delia (= Hyl~mya)antiqua (Meigen). Res. Popul. Ecd. 22: 248-241. 10. APPENDIX 10.1 ANNOTATED REVIEW OF DELIA ANTIQUA FROM LITERATURE PUBLISHED FROM 1965-1995 10.1.1 INTRODUCTION This annotated review updates the original bibliography of Scott (1 969) which chronicled >1,500 reports on the biology of Delia antiqua from worldwide sources, including the original species description in 1826 to literature current to 1966. AS with Scott's (1969) bibliography, I purposefully omitted references of taxonomic literature, spray calenders, and various control bulletins from articles puMished from 1965 to early 1995, in an effort to update published information and to identify gaps in our understanding of reproductive behaviour. In compiling this review, I principally consulted the bibliographic source, Review of Applied Entomology - Series (A) (RAE), and the literature citations of published papers. Abstracts of English language translations are provided where available from RAE. All titles enclosed in brackets [ ] denotes a English translation from a foreign hnguage publication. No annotations were given when the original abstract was not seen. Otherwise, accompanying abstracts were summarized from available papers. Citations have been divided into a general subject index, but attempts to cross reference papers which address several categories is limited. Alhara, E., N. Matsumoto & T. Muramatsu. 1985. (Dipterous Insects detected on Imported onlon bulbs with a tentative pectorlal key to larvae.]. Research Bulletln of the Plant Protection Servlce, Japan 21 : 75-80. Of Diptera collected from onion bulbs produced in Awaji Island, Japan, and from onions imported to Japan from 9 countries including USA, New Zealand and Taiwan, between October 1981 and October 1983, 15 families (17 genera and 23 species) and 8 families (8 genera and 8 species) were found on imported and domestic onions, respectively. Besides Delia antiqua and the syrphid Eumerus strigatus Fallen, other major dipterous pests found on imported onions were E. tuberculatus, Lonchaea sp., the otitids Ceroxys latiusculus, Euxesta anna and E. notata. Morphological characters of the larvae were illustrated. Altaro, R. I., H.D. Pierce, Jr, J.H. Borden & AC. Oehlschlager. 1981. Insect feeding and ovlposltlon deterrents from western red cedar foliage. Journal of Chemical Ecology 7: 39- 48. The feeding-deterrent activity of fractions from the leaf oil of western red cedar,Thuja plicata, was studied in laboratory bioassays using a cucurlionid, Pissodes strobi (Peck), as a test insect. Fractionation indicated feeding-deterrent activity in the monoterpene hydrocarbon, thujone, and terpene alcohol fractions. When tested alone, both (-)-Usothujone fils-(la, 48, k)]-4-methyl- 1-(1-methlethyl) bicyclo-j3.1.01 hexan-3-one], and (+)-3-Won0 [ (1s-(la, 40, 5a) ] -4-methyl-l- (1-methylethyl) bicycle [3.1 .O] hexan-3-one], which made Up 7548% and 510% of the leaf oil respectively, deterred feeding by the weevils. Western red cedar leaf oil also served as an oviposition deterrent for Delia antiqua. Allen, W. R. 1967. An assay for determlnlng lnsectlclde tolerance of onlon maggot larvae. Canadlan Entomologlst 99: 402-407. A laboratory method for examining dosage-response relations of early-instar larval Delia antiqua to insecticides applied to air-dried soil was described. The assay indicated that larvae from strains collected at two localities in Manitoba tolerated 50-108 x as much heptachlor as a susceptible strain from Ontario. Previously, adults from the Manitoba strains had shown high' . tolerance of heptachlor. The potencies of trichloronate (Bayer 37289) and fensulfothion (Bay 25141) relative to diazinon were 0.5 and 0.1, respectively, for one of the heptachlor-tolerant strains. For carbofuran (NIA 10242) and dichlofenthion (Nemacide), the equivalent values were 0.9 and 0.2 for this strain and 1.0 and 0.2 for the susceptible Ontario strain. Slight differences in tolerance shown for the Manitoba strains were not associated with their tolerance of heptachlor, Allen, W. R. & W. L. Askew. 1970. A simple technique for mass-rearlng the onlon maggot (Dlptera: Anthomylldae) on an artlflclal dlet. Canadlan Entomologlst 102: 15541558. Larval Delia antiqua reared for three generations on a gelatin-based diet which contained sucrose, evaporated milk, yeast hydrolysate, embryo, cellulose powder, n-dipropyl disulfide, water, were equal in puparial weights, percentages of pupation, adult eclosion, and egg hatch, to those reared on onion bulbs. Average puparid weight was 13.3 mg on artificial diet compared to 13.0 on onion. Adult eclosion on both diets ranged from 36-57% and required 29- 31 d. Two man-hours per wk was sufficient for producing 1,000 larvae daily.. czynnlka ogranlczajacego llczebnosc smletkl cebulanki- Phorbh antlqua Melg. (~jpt., Anthomylldae). Polskle Pismo Entomologlczne 46: 367375. Parasites of Delia antiqua, an important pest of onion in Pohnd where crop losses can reach 50%, were investigated in the Lublin district in 1971-73. of 4,144 Puparia and 2,007 larval D. antiqua examined, 1,937 adults of D. antiqua and 488 parasites Were recovered. The dominant parasite was T.b/iogr@a rape (Westw.) which parasitized all larval stages of D. antiqua. In high areas of infestation, rates of parasitism ranged from 20-30% to a maximum of 60%. infestations were more heavily parasitized, the average rising to 80%, and this afforded considerable protection to crops. Five parasites other than rape are recorded, but were not all identified. Andaloro, J. T., K. 6. Rose & C. J. Eckenrode. 1984. Suppmslng onion maggot In commercial flelds and research plots, and monltorlng wlth alr thermal unit rccumulatlons. Search Agriculture No. 29, S~P. Surveys of the insecticides used in commercial onion fields for the control of Delia antiqua, damage to commercial fields and research plots, and calculations of thermal constants were conducted in New York state from 19781962. Only fonofos and chloropyrifos were applied in- furrow at planting to control larvae and afforded stand reductions of<3%. The main foliar treatments against adults of 0. antiqua and the onion thrips Thrips tabaci (Lindeman) was parathion, atthough diazinon and encapsulated parathion-methyl were also used. The average number of foliar applications per grower declined from 12 per season in 1980 (the 1st year of complete spray records) to 8.5 in 1982. This was thought to be due to increased monitoring of adult flight of D. antiqua in commercial fields as a +suR of a pest management scouting program. Thermal constants computed from air temperatures measured in the vicinity of each trap site (up to 13 sites each with 2 cone traps) for 4 yr averaged 427, 1,073 and 1,785 day- degrees above a threshold of 4•‹C for 50% catch of spring and 2nd generations, and 1st flight peak of 3rd-generation adults, respectively. Anonymous. 1965. Perfumes agalnst pests. Doubleday Research Assoclatlon., Braintree, Essex, Unlted Klngdom 48 pp. The attractiveness of traps baited with essential oils resembling the food plants of a number of insect pests on horticultural crops was evaluated at 9 locations in the United Kingdom. Traps consisted of glass jars covered with 0.5 cm wire mesh and contained a sugar solution to which was added synthetic apple blossom scent or a dilution in isopropand of 1 of 11 essential oils, including gerand from the Umbelliferae. Oils of coriander, sweet fennel, Foeniculum vulgare, dill, Peucedanum graveolens, and caraway, carum d attracted relatively large numbers of Delia antqu, the cabbage maggot, Delia radicum (L.) and Euleia heraclei (L.); the first also attracted the carrot N& fly, Psila rosae (F.). Many other insects, including fruit pests and Sciara spp., were attracted in numbers, but few predators were trapped. Coriander oil at concentrations of 10% was the most effective for trapping anthomyiids. Traps baited with Barbados sugar alone were also attractive, as were traps containing only sugar solution. More insects and more species were generally attracted to Demerara sugar, Barbados sugar, West Indian treacle or golden syrup than to black treacle, cane sugar or glucose. Results of insecticide trials for the contrd of Delia antiqua on onion among other horticultural pests are present from projects conducted in The Netherlands in 1969. Anonymous. 1978. Onlon fly. Advlsory Leaflet, Mlnhtry of Agrlculture, Flsherles & hod, Unlted Klngdom No. 163 (revised), 5pp. This revised leaflet contains notes on the appearance and life-history of Delia antiqua and the seedcorn maggot, D. platura Meigen, damage to onion, leek and shallot, and methods of cultural and chemical control in the United Kingdom. Anonymous. 1979. Leo' c, Booklet, Mlnlstry of Agrlculture, Flsherles & Food, United Klngdom, No. 2069,23pp. Notes are provided on the damage and control of Delia antiqua, the onion thrips,Thrips tabaci Lind., and cutworms on commercial production of leek in the United Kingdom. Anonymous. 1981. Dlstrlbutlon Maps of Pests. 417423 and 26 & 75 (mvked), Commonwealth Institute of Entomology. Distribution maps of a number of insect pest species on agricultural crops in the United Kindom, including Delia antiqua are presented. Anonymous. 1981. International Organlzatlon for Blologlcal Control of Noxlous Animals and Plants and Organlsatlon de Lutte Blologlque contre ies Anlmaux et les Piantes Nulslblet~. EUCAR~IA/IOBCWorklng Group Breeding for Reststance to Insects & Mites. Report of the second meeting held from 9 to 11 Aprll 1980 at Canterbury, U.K. Organlsed by East Malllng Research Statlon, Maldstone, Unlted Klngdom, Bulletln SROP 4: 156 pp. Topics dealt with in papers presented at this meeting included topics on the implications of inadequate insect identification, the use of insect population simulation models in breeding for resistance, and selection of onion cultivars for resistance to D. antiqua. Anonymous. 1982. Guidelines for the blologlcal eval~ationof pesticides. Set 1, Paris, France; European & Mediterranean Plant Protection Organlzatlon. The onion thrips,Thrips tabaci Lind., and to a lesser extent, Delia antiqua are considered to be the major insects pests on leek in the United Kingdom. This booklet on leek cultivation provided information on the biology of these pests with a brief description of damage and chemical control. Anonymous. 1981. Onion maggot. Hylemya antlqua (Melgen). Insect ldentiflcation Sheet, No. 41, Agriculture Canada 2 pp. Notes are provided on the recognition, life-history, biology, damage, and methods of cuhural and chemical control of Delia antiqua, an important pest of onion, and to a less extent on leek in British Columbia, Ontario and Quebec. Arkhlpov, G. E. 1984. [Pests of onlon]. Zashchlta Rastenii, 10: 53. Notes are given on the morphology, biology, harmfulness and control of Delia antiqua, the onion weevil, Ceutorhynchus jakovlevi, the onion moth, Acrolepiopsis assectella, the onion root mite, Rh@$yphus echinopus, and the tobacco thrips, Thrips tabad Lind., infesting onion in the former Soviet Union. Eelanger, A. 1980. IResidue of insecticides In organic SO~~S.]Resldu dolnsecticldes en sols organlques. Resume des Recherches, Station de Recherches, Saint~ean,Quebec 9: 48. About 80% of the isofenphos applied as a band treatment at 2 and 4 kg per ha to field plots of onion for 2 different organic soils in Quebec, was still in the soil 8 wk after application, and gave good control of larval Delia antiqua. Up to 66% of the insecticide was present at harvest after 17 wk. +he edible portion of onion grown in soil treated at 2 kg per ha contained 0.003 p.p.m., and the corresponding residue for treatment at 4 kg per ha was 0.008 P.P.m.. Onion roots contained 3.8 and 8.1 p.p.m., respectively. Blaine, W. D. & F. L. McEwen. 1984. Nutritlon of the onion maggot, Della antlqua (Dlptera: Anthomyiidae). Canadian Entomologist 116: 473-477. A holidic diet was developed to sustain larval Delia antiqua for generation. Compared with a natural diet of onions, percent adult development was significantb higher, 85.6% vs 73.7%. Development time from egg to adult was not signficantb different between holidic diet and onions, 31.8 d and 31.7 d for males, respectively (at 20-18•‹C day-night). Development time for females ww identical, 31.1 d, for both diets. Males and females emerged from onion after 14.8 and 15.4 d, respectively. Females laid significantly more eggs On defined diet (295.9) compared with oni- (268.6). Choline at low concentrations was essential for pupation and sucrose, as a preferred energy source, may have led to an increase in egg production. The method of ch&sterd suspension was a major factor in improvement of this diet. Poorly mixed chloresterol appeared to clog mouthparts and likely decreased amount of nutrients consumed. the margin of an onion field. Three generations a Year were detected, but the third generation was only partial and had a low population densrty. Initial captures for the overwintering, Ist- and 2nd-generation adults occurred at 244.5, 1,047.3 and 1,778.5 daydegrees (DD) (above threshold of 4OC), respectively, when DD were calculated from 1 April. The flowering of the weed species Barbarea vulgaris and Epilobium angustifolium provided good visual indicators for initial captures of overwintering and 1st-generation adults, respectively. The 50% captures for these 3 generations occurred at 547, 1,343 and 1,922 DDl respectiveb. The flowering periods of both Silene cucubelus and Chrysanthemum lef~canthemumcould be employed as phenologicd indicators of the 50% captures for the overwintering generation while the flowering of Eupatorjum maculatum could be used to predict the 50% captures for the 1st-generation adults. Bol, A. 1972. !Mating behavlor of the onlon fly] Parlngsgedrag van de ulenvlleg. Doctoraal verslag blologle Rljksunlversltelt, Lelden, Netherlands 48 pp. In addition to a description of the sequences of preco~Ulat0rYphases in Delia antiqua, this study examined the effect of light and onion odours on male-female behaviour. Evidence is presented, although unsubstantiated, that onion odour stimulated males and females, and the sexes appeared to stimulate each other before mating. Brader, L. 1972. [Genetic control of the onlon fly.]. Mlttellungen aus der 81010glschen Bundesanstatt fur Land-und Forstwlrtschaft 146: 256. Techniques of rearing and sterilization for the genetic contrd of Delia antiqua were developed in the laboratory, and applied in field tests in 1971. Brader, L. 1974. lntegmted control In the Netherlands. Bulletin organlsatlon Europmnne et Medlterraneenne pour la protectlon des plantes 4: 319328. The status of practical application of a method of genetic control for Delia antiqua in The Netherlands is reviewed. To favour the marketing of produce grown under conditions when integrated contrd is practised, direct links between researchers, extension services and growers must be established, selective pesticides need to be developed, and grading standards for agricultural produce must be redefined. Broersma, D. B. & W. L. Luckmann. 1968. Frequency of matlng by the female onion maggot adult. Journal of Economlc Entomology 61: 568. Laboratory investigations on single, newly-emerged, pairs of a mutant white-eyed strain of Delia antiqua were conducted to determine if females were pobgam0~~.After intervals of 4, 8, 12 d from edosion after oviposition, red-eyes males were added to replace white-eyed males. No males mated prior to 4 d. After replacement, no females produced white-eyed and red-eyed progeny. Therefore it was concluded that females mated on& once. respectivety. A technique was also developed for rearing the A. bilineata, considered promising for the biological control of D. radicum, in puparia of D. antiqua; the yield of adults per female were 190. Trials to test the residual action of various insecticides against Delia antiqua were conducted in France in 1974 and 1977. Various Insecticides were soil-incorporated in field plots and efficacy was determined from plants sampled for damage from D. antiqua at regular intervals. Chbrpyrifos applied at 3 kg toxicant per ha, although slow-acting, was the most persistent insecticide tested. Brunel, E. & J. Mlssonnler. 1969. Comparative study of the larval development of Hylemyla antiqua Melg. (Dlpt. MuscMae) on different media, natural and artlflclal, relatlon to temperature. Mededellngen Rijksfakultelt Landbouwwetenschappen Gent 34: 696-704. Bundzhe, 2. F. 1966. Data on the blonomlcs of the onion fly (Chortophlla antlqua Melg.) In the area of tho upper Karatal basin. 1966. Trudy Kazakh. nauchno-lssled. Inst. Zashch. Rast 9: 32-36. In the Karat4 district of the Alma-Ata region of the f0mer Soviet Union, larval Delia antiqua kill up to 50-60% of unprotected onion shoots. Four generations develop each year, of which the 1st and part of the 2nd destroy mainly developing shoots, whereas succeeding generations attack only bulbs. Under field conditions, eggs hatch within 3-4 d, larvae pupate within 14-19 d, and adutt eclosim occurs 8-10 d after pupation. The greatest damage was observed in damp fields, particularly where onion had been grown for several years. Flowering weeds at the edges of the fields served as a source of food for the adults. A crop rotation of onion and rice was recommended for control. Carroll, K. A, C. R. Harrlo & P. E. Morrison. 1983. Reshtance shown by a parathion- reslstant onion maggot (Dlptera: Anthomyildae) strain to some other Insecticides. Canadlan Entomologist 115: 1519-1522. Carruthers, R. I., G. H. Whltfleld & D. L Haynes. 1984- Sam~ilngprogram for estlmatlng plant damage caused by the onlon maggot (Dlptera: Anthomylidae) on the regional and fleld levels. Journal of Economk Entomology 77: 1355-1363. Regional and field level sampling programs were developed in studies in Michigan in 1gn- 1980 to assess the damage caused by Delia antiqua to onion @ants during 1st- and Znd- generation lan/al periods. ~ogvariancebog mean regressions were used with simple and 2-stage sampling techniques to estimate sample precision for different sizes of sampling units and numbers of samples taken. Optimal sampling strategies were developed on the basis of minimizing the cost of sampling while maximizing precision. hT@Xnentati~nof the programs for 4 yr showed that the techniques were efficient, precise and useful for various applications. Carruthers, R. I. & D. L. Haynes. 1985. Laboratory transmlsslon and In vlvo lncubatlon of Entomophthora muscae (Entomophthorales: Entomophthoracae) In the onlon fly, Della antlqua (Dlptera: Anthomylldae). Journal of lnvertebrate Pathology 45: 282-287. A high-moisture infection chamber was used for the in V~VOtransmission of Entomophthora muscae within laboratory populations of Delia antiqua. This cadaver-to-fly transmission procedure provided an average experimental infection rate well above 95%. The time ftom initial exposure until host death and pathogen Sp0I'~lationwas accurately predicted using a 2nd- order function of the incubation temperature. A developmental base temperature of approximateb 5•‹Cwas estimated, with 105 day-degrees being the average number of heat units required betwen host infection and death. Transmission of E. muscae to D. antiqua and the seedcorn maggot, D. platura Meigen, was verified in the laboratory. Carruthers, R. I., D. L. Haynes & D. M. Macleod. 1985. Entomophthora muscae (Enthomophthoraler: ~ntomophthoracae)~YCOS~S In the onion fly, Della antlqua (Dlptera: Anthomylldae). Journal of lnvertebrate Pathology 45: 81-93. Entomophthora muscae was identified as a common fungal pathogen of adutts of Delia antiqua and the seedcorn maggot, 0.platura Meigen, in Michigan. LOWinfection levels were also found in populations of Pd/enia disand Coenosia tjgrina. The disease cycle, as it affects D. antiqua in the onion agroecosystem, is described, including the etiology, symptomatology and phendogy. Natural infection levels approaching 100% were noted early in spring and in late autumn, having significant affects on the adult population of the 1st and 3rd generations. A lagged denm-dependent disease response was noted at the gross population level, although more vcif~biological interactions may be involved in regulating the disease intensity. antiqua adults infected with E. muscae were also noted in malathion-treated flies, such that subsequent wnidial dispersal was highly restricted. Carruthers, R. I. & D. L. Haynes. 1986. Temperature, moisture, and habitat effecb on Entomopthora muscae (EntomophthoraleS: Entomophthoraceae) conldlal germination and survlval In the onlon agroecosystem. Environmental Entomology 15: 11541160. Gemination of conidia of Entomopthora muscae collected from Delia antiqua was quantifmd with contrdled temperature and moisture under environmental conditions similar to those in the field in Michigan. Germination rates were temperature dependent, with optimal germination near 21•‹C. Grassy border areas are the primary sites of hostlpathogen interaction since conidia germinated more readity under warm, moist conditions that typically are available in grassy border areas surrounding onion fields. This habitat also protected the conidia for limited amounts of time from dessication and harmful ultraviolet radiation. Full sunlight, over a single day can induce 100% mortality. Fungicides were also detrimental to conidial survival. Carruthers, R. I., G. H. Whlffleld, R. L. Tummaia & D. L. Hayn-. 1986. A systems approach to research and slmulatlon of insect pest dynamlco In the onion agro-ecosystem. Ecdologlcal Modelllng 33: 101-121. A systems approach, utilizing detailed ~0n~epttJali~ati0nand simulation models, was used to aid research on population dynamics of Delia antiqua and its fungal pathogen Enthomopthora muscae in the onion agro-ecosystem. The Structure and interconnections of this system, including that of the seedcorn maggot, D. platura Meigen, were outlined. In addition to the model structure and simulation methodology, program verification and model validation were also described. Chlang, M. S. & J. p. perron. 1980. Effects of seedling density and sol1 moisture on attractiveness of egg laying by the onlon maggot. Phytoprotectlon 61: 9-12. The effects of two soil moisture contents and four seedling densities of onion, ranging from 25 100 plants per 30.5 cm row, on the oviposition preference of Delia antiqua were investigated in glasshouse studies in Quebec. There was no significant difference in the numbers of eggs laid by caged females on onions in wet or dry soil. Differences among seedling densities were highb significant, those in high density receiving more eggs. These results were discussed in relation to methods used for assessing varietal resistance. Chol, S. Y., S. W. LW & 6. K. Chung. 1985. [Effdof dde-furrow-treated carbofuran (3G) on tha control of onion maggots (Hylemyla antlqua Meigen; Anthomylldae) and on the growth response of garlics]. Korean Journal of Plant ProtectJon 22: 271-276. Choo, H. Y., H. K. Kaya & D. K. Reed. 1988. [Blologlcal control of onlon maggot and tobacco cutworm wlth Insect-parasitic nematodes, Stelnernema feltlae and Heterorhabdltls hellothldls]. Korean Journal of Applled Entomology 27: 660-701. The entomop hitic nematodes, Steinemem fehb [Neoaplectana fekiae] and HeterorhabditjS heliothidis, were evaluated for the control of Delia antiqua and the noctuid Spodoptera /itura in the laboratory. Exposure of larval 0.antiqua to N. febiae at 30, 60, 120 or 240 nematodes per larva resulted in mortalities ranging from 80 to loo%, while mortality due to exposure to 10, 20, 40,or 80 H. heliothidis per larva ranged from 63.3 to 100%. Coomans, P. & A. De Gdsse. 1985. [Susceptlblllt~ of Della antiqua (Melgen) to Steinernems (=Nemplectana) blblonls (Bovlen). Va tbaarheld van Della antlqua (Melgen) voor Stelnernema (=Neoaplectana) blblonls (Bovlen). Mededellngen van de Fakulten Landbouwwetenschappen, Rljksunlversltelt Gent 50: 155-162. The effects of temperature and substrate on the susceptibility of larval Delia antiqua to the nematode Steinemem bibionis [Neoaplectana bibionis] were investigated in laboratory and glasshouse tests on leek in Belgium. Results demonstrated that 3rd-instar larvae and puparia of D. antiqua could be infected with N. bibionis, which were previously reared in the pyralid Galleria mellonella. Larval D. antiqua ceased feeding soon after infection. Cowl-, R. S., J. E. Keller 81 J. R. Mlller. 1989. Pungent splces, ground red pepper, and synthetic capsaicin as onlon fly ovlpostlonal deterrents. Journal of Chemlcal Ecology 15: 719-730. In laboratory choice experiments, the spices dill, paprika, black pepper, chili powder, ginger, and red pepper deterred oviposition of Delia antiqua by 88-100%. Dose-response choice tests demonstrated that 1 mg of ground cayenne pepper (GCP) placed within 1 cm of artificial onion foliage reduced oviposition by 78%. A synthetic analog of capsaicin, the principle flavor ingredient of red peppers, deterred oviposition by 95% When present at 320 p.p.m. in the top centimeter of sand. However, in no-choice conditions 10 mg GCP was not an effective deterrent. Capsajcin-based materials do not appear to be candidates for contrd via behavioural modification. Cowles, R. S., J. R. Miller, R. M. Holllngworth, M. 1. Abde1-W F. Szurdokl, K. Bauer & G. Matolcsy. 1990. Clnnamyl derlvatlves and monoterpenold~as nonspeclflc ovlposltlonal deterrents of the onion fly. Journal of Chemlcal Ecology 16: 2401- 2428. Physical and biologic& factors that effect oviposition preference of female Delia antiqua for sprouted cull onions were examined in a field trial in Michigan. Microplots (2.5 m long) of sprouting onion bulbs, planted 5 cm deep, received an average of 2,300 eggs of 0. antiqua during a 3 wk period. Plots with bulbs resting on the soil surface, planted with their neck at the soil surface, or at 12 cm depth, received 280, 1,530, and 980 eggs, respectively. Damage to sprouting bulb caused by slicing, infestations of larvae, Or both did not enhance or diminish oviposition compared with intact bulbs, under laboratory ~onditions. Egg laying was equivalent for all treatments as long as green, moist foliage was present. The effectivenes of cinnamaldehyde (an ovipositional deterrent) and cull onions (an ovipositional stimulant) to protect onion seedlings was evaluated under glasshouse conditions. Interaction between deterrent and culls wss consistent with a multiplicative model where the probability of a female accepting seedlings was reduced independently by the presence of deterrent or culls. Resub suggested that stimulo-deterrent diversion is a valid form of control, albeit not yet practical for 0. antiqua. Cruger, G. & M. Hommm. 1990. [Pests and dlseases of leek.] Krankhelten und Schadllnge an Porree. Gemuse (Munchen) 26: 130-135. Dabrowski, 2. T., Adamowlcz, W. & Glelata, 1. 1968. [Experiments on the control of the cabbage fly and the onion fly]. Doswladczenla nad zwalczanlem smletkl kapusclanej I smletkl cebulankl. Rocznlkl Nauk Rolnlczych, InStYtut Ochron~Roslin 93: 805-821. Field tests were conducted in Poland from 1965-66 to evaluate 13 compounds for control of Delia antiqua on onion. Compounds were tested as granules or as a seedling drench before planting. Insecticides were not phytotoxic, with the exception of endosutfan. Of insecticides applied ss granules, disulfoton and dimethoate reduced damage to onion by 12.7 and 18.6%, respectively, in 1965 as compared with 30.5% for the control treatment. In 1965, dieldrin, mixtures of aldrin and dieldrin, gamma BHC and Phen~lmercuVoctane, and thiram and aldrin, reduced damage to 8, 6.6, 9.4 and 18.2%, respediveb, as compared with 30.5%. In 1966, 50% dichlorvos and diazi- reduced damage to 14.7 and 15.2% respedively, compared with 58% damage in controls. Dansrru, J. 1978. IEvaluatlon of lnsectlcld~against the onion fly (Hylemya antlqua).] Evaluation dw Insecticides contre la mouche de I'oignon (Hylemya antiqua). Resume ti- Recherches, Station de Recherches, SaintJean, Quebec 7: 44. infestation. Examination of larvae revealed that 98% were S. ~~ridaand the remaining 2% Delia antiqua. of7 PUS planted the previous spring, 5 were uninfested while 2 had infestations of 0, antiqua of 28%. is suggested that S. lurida may be controlled by spring planting of garlic. White pan traps and yellow sticky traps were less attractive to the pests than expected and are not recommended for forecasting. Davis, A C. & R. J. Kuhr. 1976. Dlsslpatlon of chlor~~rlfosfrom muck soil and onions. Journal of Economlc Entomology 69: 665-666. In-furrow applications of emulsion concentrate and granular formulations of chlorpyrifos at rates of 0.4 or 0.9 kg toxicant per acre for control of larval Delia antiqua on persisted at concentrations above 1 p.p.m. for 16 wk in muck soil in New York State in 1975. When compared with the emulsion concentrate, the granules produced a slightly higher initial concentration of insecticide and dissipation occurred at a slower rate. Chlorpyrifos residues in plants never exceeded 1 p.p.m., and most of this was confined to the outer wrapper leaves. Do Flutter, H. G., J. P .W. Noordlnk & J. H. G. Ticheler. 1967. The onlon fly problem and the sterile male technlque. Meded. Reactor Centrum Nederl. 20: 83-97. Chemical contrd measures that have been applied in The Netherlands for the control of Delia antiqua on onions are reviewed, and methods of laboratory rearing for control by the sterile male technique are discussed. Dlndonls, L. L. & J. R. Miller. 1980. Host-flndhg behavior of onion fib, Hylemya antlqua. Environmental Entomology 9: 769-772. Host-finding behaviour by female Delia antiqua, in response to sliced onions, barnyard grass (Echinochloa sp.), and a control treatment, was observed in a field study in Michigan. More adults landed within 0.5 m of an onion bait than within 0.5 m of any of the other treatments. Females which landed downwind of the onion bait flew directb Or in a series of short flights toward the volatile source. These behaviours were not observed in the vicinity of the other treatments. Traps designed to assess flight direction with respect to the wind substantiated the observations of female and male upwind flight in response to distant host-plant odours. These results show that adults locate host plants as a result of positive taxes, of which anemotaxis plays a significant role. Dlndonls, L. L. & J. R. Miller. 1980. Host-finding rmponsw of onlon and seedcorn flies to healthy and decomposing onions and several synthetic constttuents of onion, Environmental Entomology 9: 467472. antiqua. The apparent advantage of female preference for the decomposing onion would be increased larval survival due to easier larval penetration of onion bulbs and faster larval development. Dlndonls, L. L. & J. R. Miller. 1981. Onion fly trap catch as affected by release rates of n- dlpropyl dlsulflde from polyethylene enclosures. Journal of Chemical Ecology 7: 411- 418. The effects of five different loadings of n-dipropy1 disutfide (DPDS), leading to a range for maximal trap catch of adults of Delia 8ntEque was investigated from traps placed near the border of a commercial onion field in Michigan. Aduk were responsive to a wide range of DPDS emissions (1, 10, 100, and 10 x 100 pi). Trap catch plateaued at the highest rate. Data indicated a possible attendant close-range repdbncy Or arrestment of incoming flies as doseage increased. High release rates may elicit long-range flight but may deter landing at the source, or possibly induce flight arrestment. In potyethylene ca~suhDPDS was emitted at 60 pg per h to 9 mg per h from 1 PI and 10x100 pI, repectively. No difference in trap catch was seen for the control, sliced onion or 1 p1 treatment. Dlndonls, L. L. & J. R. Mlller. 1981. Onion fly and little house fly host flndlng selectively mediated by decomposing onion and mlcroblal volatlltw. Journal of Chemical Ecology-7: 41 9426. Responses of aduks of Delia antiqua to various synthetic onion and microbial volatiles as well as vdatiles from microbial cultures and decomposing Onions were tested to characterize the most effective host-finding stimuli, in field triais in Michigan. Of nine onion and microbial volatiles tested individually, only the known attractant, n-di~ro~~ldisuffide (DPDS), caught significant numbers of flies. However, a blend of these vdatiles attracted more flies than my single chemical, including DPDS. In andher experiment, agar plates inoculated with microorganisms from decomposing onions did not attract adult D. antiqua. However, cut onions inoculated with micrmgmisms and conditioned 4 d caught more adult D. antiqua than freshly cut onions and DPDS. These results suggest that a blend of chemicals rather than a single key chemical is the most effective host stimulus, and that microbial activity enhances the attractanv of blends of onion volatiles. Large numbers of the little house fly, Fannia canicularis, reSpnded to the microbial cultures, demonstrating the exi~tan~eof a potent attractant for this muscid. Driesche, R. G. van, D. N. Form & C. Holllngsworth. 1987. Potential for Increased use of blologica~control agents agalnst vegetabb pb. Research Bulletin, Massachusse& Agrlculturrl Experiment Station 718: 05-74. The bionomics of Delia antiqua on onions, in New York State is summarized towards the goal of finding ahernative strategies to chemical control. LOWdamage levels were recorded in small, isolated fields which bed been planted with a rotational crop the prevlous spring. High levels of damage were observed in small plots in organic soils 0.41.5 km from overwintering sites. lt concluded that the 1st generation could be suppressed if whole areas were rotated out of onions. It is recommended that mechanical injury to the crop should be avoided and damaged bulbs should be removed from the field, as these provide a food source for overwintering populations. Eckenrode, C. J. a J. P. ~yrop.1986. Impact of ~h~slcalWV and ~~mmerclallifting on damage to onlon bulbs by larvae of onlon maggot (Dl~tera:Anthomylldae). Journal of Economlc Entomology 79: 1606-1608. The impact of 2 types of physical injury and 3 methods of commercial lifting (uprooting) of onion before drying and harvest on attack by larval Delia antiqua was assessed in field studies in New York State in 198485. Bulbs that were cut and bruised received more injury due to larval attack than those that were not physically injured. Comparisons using 3 types of power-driven commercial lifters indicated that onions uprooted by a potato digger and then windrowed were least amaged (14.8% in 1984 and 3.7% in 1985) while onions that had been undercut sustained the most damage (26.0 and 8.6 %, rw~ectivel~). Eckenrode, C. J., E. V. Ver & K. W. Stone. 1975. Population trends of onion maggob correlated wlth air thermal unlt accumulations. Environmental Entomology 4: 785-789. Laboratory studies using 8 constant temperatures established a threshdd of 4.4"C for adu)t eclosion of aduh Delia entiqua. Using n-dipropyl disulfide as an attractant in field experiments in New York State, proportionately more males than females were trapped. Average air thermal unit accumulations for 50% catch of spring, 2nd and third generations was 71 2, 11 87, and 1257, respectively. Earb- and late-season damage, from 3 distinct generations per year, closeb followed the population trends.lncorporation of temperature accumulations, earliest dates of population buildup, and field monitoring provided growers with an earb-warning system. Ellls, P. R. & C. J. Eckenrode. 1979. Factors Influencing teslstance In Alllurn sp. to onion maggot. Bulletin of the Entomological Soclety of Amerlca 25: 151-153. Field trials on a range of varieties of onion, Allium spp, at 3 sites in New York State, and glasshouse and laboratory evaluations were conducted to determine onion resistance to larval damage from D*& antiqua. Japaness bunching onions, A. fistul~S~m,were less damaged than bulbing varieties, A. cepa. Bulbing varieties were attacked to the same extent regardless of pungency or time of maturity. Onions were less damaged when transplanted than when direct- seeded in the field. Glasshouse studies suggested that the midaf~ceof Japanese Bunching seedlings was due to nonpreference. Laboratory studies, using variations of sterilized soil and seed,showed that m~ectionof hosts for oviposition by D. antiqua females may be governed by microbial activity on or near the plant. The nature of resktance in Allium species and onion varieties, attractiveness of plants and factors affecting the establishment and survival of larvae on the host are discussed. CuJtivars of A]/ium fistulosum were more resistant to damage from Delia antiqua than cultbars of A. cepa in 3 different field sites in New Yotk State. Bulbing varieties (A. cepe were attacked to the same extent regardless of pungency or time of maturity. Onions were less damaged when transplanted than when direct-seeded in the field. Glasshouse studies suggested that the resistance of Japanese bunching seedlings was due to nonpreference. Laboratory studies showed that selection of hosts for oviposition by female D. antiqua may be governed by microbial activity on or near the plant. Ellb, P. R., S. K. Son1 & H. J. Mayne. 1986. ResMance of vegetables to Insect pests. Onlons. IN: 36th Annual report 1985, National Vegetable Research Station, Wellesbourne, Unlted Kingdom p. 31. In glasshouse tests, some progenies from partially resistant Allium cepa families were 21% less damaged by larvae than their parents. Of 380 cdtivars and lines screened, about 30 were partially resistant to Delia antiqua in the glasshouse; most were confirmed as less damaged than a standard susceptible cultivar. There was large variation in the numbers of eggs laid by flies in the laboratory around plants of different ages of 32 partidly resistant cuttivars. Emmett, B. J. 1982. Evaluation of seed tmtmenb for control of onion fly: 1981. Annals of Applled Biology 100: 30- 31. Field-plot tests were carried out in Essex, England, in 1981 to evaluate the effectiveness of seed treatments with different insecticides for the contrd of Delia antiqua on salad onions. lodofenphos applied at 10 g toxicant per kg seed was highty effective against a severe attack in early June and also gave adequate protection from 2nd-generation larvae in late summer. Brornophos at 25 g toxicant per kg seed gave moderate protection. Residue levels of the insecticides were below the tolerance limits. Emmett, 8. J. & M. J. Savage. 1980. Chemlcal control of 0nl0n fly, Della antlqua (Melg.). Plant Pathology 29: 159-167. Emmett, B. J. 1981. Onlon fly. Leaflet, Minlstty of Agriculture, Flsherles & Food, United Klngdom, No. 163, Spp. The impact, morphology, life-history and control of larval Delia antiqua which is widely distributed in the United Kingdom, sometimes cause Serious damage to onions, particularly in gardens and allotments. Leeks and shallots are also attacked. Eymann, M. & W. G. Friend. 1983. Onlon maggot development In a bacteria-rich environment wlthout onlon tlssue. Proceedings of the Entomologlcal Soclety of Ontarlo, 114: 99-100. A cellulose wick contaminated with bacteria of Escherichia coli supported the growth and reproductive development of larval Delia antiqua to adulthood in the laboratory. Atthough the host range of 0.antiqua appears limited to a specific range of members in the genus Al/ium, observations here indicated that Allium tissues do not supply any exotic essential nutrients. Eymann, M. & W. G. Frlend. 1985. Development of onlon maggots (Dlptera: Anthomylldae) on bacteria-free onlon agar supplemented with vitamins and amlno aclds. Annals of the Entornologlcal Society of Amerlca 78: 182-185. Larval Delia antiqua developed to the adult stage on onion agar (macerated onion in agar) under axenic conditions only if the agar was supplemented with a mixture of 8 water-soluable vitamins and 10 essential amino acids. The omission of supplemental arginine or tryptophan had little effect on development. The omission of supplemental histidine, lysine, or phenylalanine resulted in suboptimal development to the adult stage. Without supplemental threonine, leucine, isoleucine, valine, methionine, or the vitamin mixture, no development occurred past the third stadium. Nutrients that are in insufficient supply in certain onion tissue are presumably supplied by bacteria in nature. Eymann, M. & W. G. Friend. 1985. Effects of vitamin supplements on the development of onlon maggots (Dlptera: Anthomylldae) on axenlc onion agar. Canadlan Entomologist 117: 475479. Under axenic conditions, larval Delia antiqua developed to the adult stage on onion agar only if the agar was supplemented with mixtures of 10 essential amino acids and 8 water-soluble vitamins. The omission of the amino acid mixture allowed no development past the 1st instar. When the vitamin mixture was omitted, 1 of 25 larvae developed to the pupal stage. Omission of individual vitamin supplements (supplemented choline, thiamine, pyroxidine or pantothenic acid) had no significant effect on development. But omitting biotin or nicotinic acid resulted in suboptimal development to the adult stage. Without riboflavin or folic acid larvae reached development to the adult stage, but females did not lay viable eggs. Presumably, nutrients that are in short supply in onion tissue are provided by bacteria in nature. Flnch, S. 1989. Ecological conslderatlons In the management of Della pest specles In vegetable crops. Annual Review of Entomology 34: 117-137. Advances in crop protection tactics for Delia spp. of agricuttural importance, most notably methods of cultural, chemical, and biological control for the cabbage maggot, D. radicum (L.), and D. antiqua, are included in this review of research conducted in mainland Europe, North America, and the United Kingdom. Emphasis is placed on the progress and difficulties of integrating noninsecticidal methods of crop protection into a program of pest management employing judicious amounts of insecticide. Flnch, S., M. E. Cadoux, C. J. Eckenrode & 1. D. Splttler. 1986. Appralsal of current strategb tor controlling onlon maggot (Dlptera: Anthomylldae) In New York State. Journal of Economlc Entomology 79: 736-740. Chloropyrifos applied in the furrow at planting in mid-May to control infestations of Delia entiqua gave adequate control for 8 wk (mid-July) in New York State. In laboratory and field tests, undamaged onions grown with or without insecticide treatment became resistant to invasion of larvae after 12 wk of plant growth (about mid-August in all but one field). Larvae died primarily through failing to establish on the bulbs rather than through dessication. Late s-n (third-generation) damage was most prevalent in rows where plants had been damaged during weekly applications of parathion sprays. Control of D. antiqua control may be improved by development of a more persistent soil tre&tIent, selection of onion cultiars with midseason resistance to invasion, and effective adulticide treatments for midseason application. Flnch, S. & R. H. Colller. 1989. Effects of the angle of incllnatlon of traps on the numbers of large Diptera caught on stlcky boards In certain vegetable crops. Entomologla Experlmentalls et Appllcata 52: 23-27. The effectiveness of sticky traps versus water traps to monitor Delia antiqua, the turnip maggot, D. floralis (Fallen), the seedcorn maggot,D. platura Meigen, the cabbage maggot, D. radiwm (L.), and the carrot rust fly, Psila rosae, were investigated in a series of field experiments in England. Preference of species for landing on trap surfaces of a particular plane was also examined. Using field plots and field cages, one-sided, yellow sticky traps were aligned in one plane but oriented in eight directions. Of 400 D. antiqua captured, adults preferred to land on either horizontal surfaces or those with the sticky surface facing upwards and inclined at 45" to the vertical. These results were comparable with other Delia spp. Flnch S. & C. J. Eckenrode. 1985. Influence of unharvested, cull-pile, and volunteer onions on populatlons of onlon maggot (Dlptera: Anthomylldae). Journal of Economlc Entomology 78: S2-546. The relative contributions to the overall population of Delia antiqua developing on unharvested bulbs, cull piles, and volunteer onions was examined in field, glasshouse, and laboratory experiments in New York State in 1983. Contribution of adults from cull piles was related to surface area of the pile. Puparia buried 30 to 40 cm deep did not survive. When eggs were inoculated on cull piles during the summer months, no flies developed. Placing discarded onions in deep piles will thus minimize the numbers of adults emerging in the spring. Females preferred to oviposit on large intact volunteer plants rather than on small onion seedlings. However, compared with unearthed bulbs, volunteer plants were not suitable for onion maggot development in the glasshouse or the field. This was attributed to the poor ability of larvae to become established on undamaged volunteer onions in the spring. Thus, removal of volunteer plants does not seem necessary. However, onion bulbs that are left at harvest or otherwise damaged, support third generation larvae. If not removed by early October or tipped into deep cull piles, this waste crop will contribute to a large overwintering pupal population. It was estimated that 0.06 to 0.67 million puparia per ha overwintered in soil containing boiler onions and bulb onions, respectively. Flies emerged from at least 95% of these puparia in the spring. Flnch, S., C. J. Eckenrode 81 M. E. Cadoux. 1986. Behavlor of onlon maggot (Dlptera: Anthomylldae) In commercial onlon flelds treated regularly wRh parathion sprays. Journal of Economlc Entomology 79: 107-113. A field study to evaluate the effectiveness of parathion as an adulticide for Delia antiqua, based primarily on numbers of adults captured in yellow, onion-baited, water-traps, reports several aspects of the adult behaviour of Delia antiqua in New York State. Traps placed alongside five overwintering sites from 25 May to 1 June, and near patches of dandelion (Taraxacum offidnale) caught 3,893 males and 81 3 females (sex ratio 1 :I). No more than 6 females were caught per trap per d alongside any field during the spring trapping period. ~t peak spring eclosion, only 13% of females emerged per dl all before 0800 h. Flies did not remain long at the edosion site. It was usual to catch more males than females in traps placed along the boundaries of onion fields, presumably because females spent a greater proportion of their time within the crop searching for suitable oviposition sites. Fly activity was crepuscular, most flies were caught before 0800 h and after 1800 h in traps placed within a commercial field of onions. Once active, flies were distributed evenly through the crop; most females were caught in the evening. Gravid females may move into the crop in the evening and return to the hedgerows the following d. Flies aggregated where there were suitable sources of food, shelter and water. Adult D. antiqua were observed feeding during the early morning from the flowers of grasses, dandelions, and milkweed (Asclepias syriaca) and drank from dew and guttation on onion plants, but avoided onion crops during most of the day, preferring to rest in the shade of surrounding foliage at hedgerows. Shelter was extremely important in midday when flies moved away from the sun and became inactive. Water also had a positive influence on distribution. Because of the distribution of flies and the fact that parathion had to make direct contact to be effective, sprays applied at the sites of edosion in bare fields, at feeding and resting sites in hedgerows, or at oviposition sites in the onion field, would kill too few adults to affect the overall population. Flnlayson, D. G. 1965. Efflcacy of several organophosphorus compounds agalnst cyclodlene-reslstant onlon maggots. Proceedings ot the Entomological Soclety of Brltlsh Columbia 62: 3-8. The efficacy of carbophenothion, diazinon, ethion and endrin for the control of Delia antiqua on onion was evaluated in field trials in British Columbia. Compounds were applied as granular formulations to the furrow at 0.45 kg or 0.91 kg toxicant per 0.4 ha or as wettable powder to the seed at 26 ml per 0.45 kg. Captan was also added to half of each plot to evaluate smut control. The three organophosphate insecticides (carbophenothion, diazinon, and ethion) gave good to excellent protection in mineral and peat soil. Endrin, to which resistance had arisen, allowed various amounts of damage up to 78.5%. Compounds had little or no effect on seedling emergence, or other phytotoxic symptoms, with the exception of diazinon which caused considerable reduction in the number of emergent seedlings, especially in sandy loam soils. The average yields of marketable onions in kg from 609.6 row meter (20 row-feet ) were 6.7 for ethion, 6.6 for carbophenothion, 6.5 for diazinon, 5.9 for endrin and 1.2 for no treatment. Frank, R., H. E. Braun, G. Rltcey, F. L. McEwen & G. J. Slrons. 1982. Pestlclde residues In onlons and carrob grown on organic rolls, Ontario 1975 to 1980. Journal ot Economlc Entomology 75: 560-565. In field surveys and experiments carried out in Ontario between 1975 and 1980, levels of pesticide residues to control Delia antiqua were assessed in onions and carrots. Residues were determined for onions treated at planting, in the windrow, and carrots in rotation with onions. Because of insecticide resistance and heavy dependence on ethion in 1975, 38% of onion samples (n=8 farms) contained ethion residues above the 100 u per kg negligible level. In 1978, with less dependence on ethion, only 3% of onions from a similar survey had such residues. In field experiments in 1978 and 1979, ethion, chlorfenvinphos, chlorpyrifos, fensulfothion, fonofos, kfenphos and terbufos gave residues c100 by per kg in dry onions, with the exception of the highest application rate of ethion (4.5 kg per ha). When onions drying in windrows were treated with parathion and diazion, residues fell below the permitted tolerances at 1st sampling 3 and 7 d later, repectively. In experiments in 1979, residues of cypermethrin, permethrin and parathion fell below 100 ug per kg in 7, 1 and 3 dl respectively, when applied to onions drying in windrows. In 1980, initial residues on onions treated in the windrow were c100 ug per kg. Residues in the soil from insecticides applied against D. antiqua on onions in 1975, 1976 and 1977 resulted in residues of c100 ug per kg in carrots grown and harvested in the following seasons. Frimche, R., S. Thlele & D. Otto. 1982. [The occurrence of onlon flles (Phorbla antlqua Meigen) and a test for showing their resistance to lnsectlcides.] Auftreten und Entrcheldunrptest zum Nachweb von Insektlzldreslstenz be1 zwlebelfllegen (Phorbla antiqua Meisan). Nachrlchtenblatt fur den Pflanzenschutz In der German Federal Republlc 36: 164-165. A test for determining insecticide resistance of larval Delia antiqua, based on various degrees of damage to onion, was developed. Results indicated that a field population of 0. antiqua in the German Democratic Republic had developed considerable resistance to seed treatments based on DDT, because of its long-term application. H~wever,larvae were susceptible to seed applications of bromophos. Galle, F. & M. Loosjes. 1987. [Practical appllcatlon of Insect-parasltlc nematodes and sterlle flles.] Praktlsche Anwendung insektenparasltlscher Nematoden und sterillslerter Fllegen. Schhrlttenrelhe des Bundesmlnlsters fur Ernahrung, Landwlrtschaft und Forsten, A (angewandte Wlssenschatt), German Federal Republic 344: 269-274. A description is given of the use of the sterile-male technique to control Delia antiqua in The Netherlands. A 20-fold excess of released sterile males over normal males in onion fields was effective in 10% of the onion-growing area tested. It was, however, complex and labour intensive. GeWn, L. W. 1973. Suppression of onlon thrips with systematic-insecticide roll treatments. Journal of Economic Entomology 66: 975-977. Applications of carbofuran and fensulfothion to the seed furrow at rates of 14 and 28 g toxicant per 305 m of row were evaluated principally for the control of Wpstabaci Lind. on onion in field plots in eastern Washington during 1970-72. The insecticides were also effective in controlling larval Delia antique. Gherasim, V. 1976. [The bulb fly- Eumerus strlgatus Fall. (Dlptera- Syrphldae) a pest new to onion crop In the Republic of Romania.] Musca bulbllor- Eumurus strlgatus Fall. (Dlptem- Syrphldae) un daunator nou al culturllor de ceapa dln R.S. Romania. Analele lnstltutulul de Cercetarl pentru Protectla Plantelor 11: 141-146. The occurrence of Eumerus strigatus (Fall.) in onion bulbs was reported for the 1st time in several southern and eastem districts in Romania in 1973. During the early part of the season, syrwa larval E. strigatus were found in plants infested with larval Delia antiqua. Yield losses of 10-15% were recorded on late-maturing varieties. The syrphid has 2 generations a year in Romania and overwinters either in the pupal stage in the bulbs or the soil or in the adult stage in the soil. Females laid 35100 eggs each, which hatched in 3-10 d. At 21-23"C, larval and pupal stages lasted 20-30 and 7-12 d, respectively. In some samples of infested onions, the larval saptophagous insects such as Syritta pipiens (L.) were also recorded. Ghemslm, V. 1985. [Entomophthora muscae (Cohn) Fres., a pathogen wldespread In populations of onlon fly- Della antlqua Me1g.- from Romanla.] Entomophthora muscae (Cohn) Fres. agent patogen rasplndit In populatli de musca cepel- Della antlqua Melg. din Romanla. Analele Instltutulul de Cercetari pentru Protectla Plantelor 18: 137-146. Entomophthora muscae was recorded from Delia antiqua for the 1st time in Romania in 1976- 80. Low temperatures and high rates of humidity in midJune, late July and mid-August, in conjuntion with dense plant growth and furrow irrigation, created conditions favourable for E. muscae. A high incidence of infection was observed on adult D. antiqua that prevailed until late August in 1980. Ghemslm, V. & M. Lacatusu. 1977. [Aphaereta mlnuta (Nees) (Hymenoptera-Braconldae), prlnclpal tactor Ilmltlng the populatlons of Dlptera Injurious to onlon crops In the Soclallst Republlc of Romanla.] Aphaereta mlnuta (Nees) (Hymenoptera-Braconldae), prlnclpalul factor llmltatlv a1 populatlllor de dlptere daunatoare cutturllor de ceapa din R.S. Romanla. Analele Instltutulul de Cercetarl pentru Protectla Plantelor 12: 229-236. Studies carried out in 1972-75 on onion crops in several districts of Romania showed that Delia antiqua, in conjunction with other phytophagous and saprophagous Diptera, caused 15-62% damage to bulbs. The braconid Aphaereta minuta (Nees) was the predominant parasitoid accounting for 95.3% of total parasitoids. The pteromalids Spalangia cameroni Perkins and Pachycrepoideus dubius Ashm. were also present, but formed only 4.7% of the total parasite population. Parasitism by A. minuta of larval D. antiqua, its main host, was 73.9%. Eumerus strigatus (Fall.), which also damaged onion bulbs to a lesser extent, formed 6.5% of the hosts, and the remaining 19.6% of the hosts was comprised of the saprophagous dipterans Muscina stabulans (Fall.), M. assimilis (FalI.) , Fannia canicularis (L.) and Anthomyia pluvialis (L.) that were often present in infested onion bulbs). The highest level of parasitism was observed in August-September, which corresponded to the 2nd and third generation of 0.antiqua. Ghemslm, V. F. & A Marln. 1987. (Populatlon fluctuatlons of the onlon fly (Della antlqua Melgen) recorded by captures In coloured sticky traps.] Fluctuatla populatlel daunatorulul muscr cepel (Della antlqua Melgen) evldentlata prln capcane colorate cu strat adezlf. Buletlnul do Protectla Plantelor 1: 29-38. Adult Delia antiqua were monitored in onion fields in Romania over 220 d in 1983. Four white sticky traps were placed in each field. Fluctuations in the pest population were recorded in the overwintered, 1st and 2nd generations. The sex ratio was in favour of males, averaging 6.41. Golx, J. 1986. [The onlon fly.] La mouche de I'olgnon. Phytoma 376: 45-46. Notes are provided on the biology, damage and methods of cultural and chemical control for larval Delia antiqua infesting onion in France. Dosages and modes of application are given for 10 insecticides used for pest control. ~ostlck,K. G. & Coaker, 1. H. 1969. Monitoring for Insecticide resistance In root flies. 1: 89-92. Resistance to cyclodiene insecticides is reported from England in Delia antiqua, the cabbage maggot, D. radicum (L.), the seedcorn maggot, D. platura Meigen, and the carrot rust fly, Psik rosae (F.). Resistant individuals were detected with topical application of discriminating doses of insecticides. Most species were sufficiently mobile for sampling at intervals of 2-3 miles to provide a reliable indication of the incidence of resistant strains. A review of their current distribution in England was presented. Gostlck, K. G., D. F. Powell & C. Slough. 1971. Dieldrln reslstant onlon fly (Della antiqua (Meig.)) in England. Plant Pathology 20: 63-65. In 1969, seed-dressings of dieldrin failed to control Delia antiqua on onion in a few locations in central and eastem England. By 1970, development of resistance to dieldrin was confirmed by comparing the resistance of field-collected adults to dieldrin applied topically in 2 mi of 2- ethoxyethanol with that of a known susceptible strain from France. Goth, G. J., W. G. Welllngton & H. Y. Contant. 1983. Variation due to maternal age in the onion root maggot, Hylemya rntlqua (Meigen). Researches on Population Ecology 25: 366- 386. Age of adult female Delia antiqua affects the heterogeneity of progeny in the laboratory. Ea*- ecWprogeny were more successful in terms of mean expectation of life, mortaltty rate at mid-life, average fecundity, mean rate of egg production, and percentage female progeny. Mid- eclosed progeny were the hardiest in terms of sustained mortalrty rate and abiltty to survive food stress. Progeny from eggs laid by females late in life were the most mortality-prone and least fecund, but had the shortest mean generation time. Maternal age also affected pupal size. Graflus, E. & F. W. Warner. 1989. Predation by Bemblodlon quadrlmaculatum (Coleoptera: Carabldae) on Delk antiqua (Dlptera: Anthomylldae). Envlronmental Entomology 18: 1056-1059. The feeding rate and efficiency of a carabid predator of D. antiqua eggs and first instars was evaluated in the laboratory and field. Adult 6. quadrimaculatum consumed up to 25 eggs per d and reduced egg numbers up to 57% in field cage studies. Grill, D. 1985. medkeases and pests of the leek.] Les maladies et ravageurs du poireau. Phytoma 371: 3941. Notes on the biology of the major pests of leek in France (notably Delia antiqua), information on plant damage, methods of chemical control, and monitoring are provided. Grlll, D. 1988. pegetabk crops. Nantes: rearing and monltorlng fllght periods of fly pests In vkw of adapted control.] Culturer legumieres. Nantes: elevation at observation des vols de mouches nulslbles en vue doune lutte rdaptee. Phytomr 398: 44-46. Methods used for monitoring D. antiqua, the cabbage maggot, 0.radicum (L.), the seedcorn maggot, D. platura Meig., and the carrot rust fly, Psila rosae (F.) in the region of Nantes in western France were described. Using weather recording, cdoured pan traps and rearing flies under field conditions, it was noted that D. antiqua and D. platura each had 3 generations a year, comparable to P. rosae. Delia radicurn had 4 or 5 overlapping flight periods. Based on these observations, recommendations for chemical control of the 4 species was presented. Groden, E. 1982. The blology of two parasltolds of the onlon maggot, Hylemya entiqua (Melg.) and the potentlals for management M. Sc. Thesls, Mlchlgan State Unlverslty, E. Lansing, MI 353 pp. Guerln, P. M. & E. Stadler. 1982. Host odour perception In three phytophagous Diptern - (I compamtlve study. Proceedings ot the 5th lnternatlonal symposlum on Insect-plant relationships, Wageningen pp. 95-1 05. A high degree of olfactory specificity Was observed by means of the electroantennogram (EAG) in Delia antiqua and the carrot rust fly, Psila rosae (F.), for the host-related propyldisutfide and tram-asarone (2,4,5-trimethoxy-1-propenyl-benzene) , respectively. Delia radicurn (L.), by comparison, showed less specificity for allylisothiocyanate with an optimal EAG response to dimethyldisulfide. While D. antiquawas selectively tuned to the perception of leaf alcohols and P. rosae to leaf aldehydes, the olfactory receptors of D. radicum demonstrated no selectivrty to a single functional type of green leaf volatile. Aliphatic aldehydes of between 7 and 9 carbon atoms evoked the highest EAG responses in all three oligophagous species. Their sensitivrty spectra to individual host volatiles were reflected in EAG responses to headspace vapours over host and nonhost foliage. Haddow, B. C. & T. G. Marks. 1969. iodofenphos-a broad vlew of a promlslng new Insecticide. Plant Pathology 19: 531437. lodofenphos, an organophosphorus insecticide of low mammalian toxicity, was effective as a contact and stomach poison against a wide range of insect pests including Delia antiqua, the cabbage maggot, D. radicurn (L.), and the seedcom maggot, D. platura Meigen. Haegermark, U. & C. E. Rantzer. 1970. Diadnon-resisance in the onion fly (Hylemyla milqua Melg.) Dhzinonreslstens hos lokfluga (Hylemyla antlqua Melg.) 1970. Vaxtskyddsnotiser 34: 12. First indications in Sweden of localized resistance of Delia antiqua to the insecticide diazinon were noted in 1968-69. Harris, C. R. 1972. Cross-redstance shown by susceptible and aldrln-reslstant stralns of seedcorn maggots, onlon maggots, and cabbage maggots to chlordane. Journal ot Economlc Entomology 65: 341 -347. Harrls, C. R. 1QTI. Insectklde reslstance in sol1 Insects attacking crops. Pestlclde Management and Insectlclde Resistance. pp. 321-351. A review is presented of the development of resistance to insecticides in soil insect pests, and tables are provided showing the species that have been recorded as developing resistance to organochlorine compounds (31 species since 1954) or organophosphorus compounds (3 species) or both. There is no evidence of soil insects having developed specific resistance to carbarnate compounds, but the non-specific organophosphate resistance developed by Delia antiqua in some regions of North America has also resulted in resistance to carbofuran. Harrls, C. R. & G. 6. Klnoshlta. 1977. Whence of post-treatment temperature on the toxlclty of pyrethrold Insectlcldes. Journal of Economlc Entomology 70: 215-218. Harrls, C. R., G. F. Manson & J. H. Mazurek. 1962. Development of lnsectlcldal reslstance by sol1 Insects In Canada. Journal of Economlc Entomology 55: 777-786. Results of tests conducted on Delia antiqua collected from a number of areas in Canada, indicated that adults were susceptible to aldrin and dieldrin, but resistant to cyclodienes. This report confirmed the observation of development of cyclodiene resistance in southwestern Ontario in 1958. Harris, C. R. & H. J. Svec. 1976. Onion maggot resistance to Insectlcldes. Journal of Economlc Entomology 69: 617-620. The susceptibility of field and laboratory strains of adutt Delia antiqua to representative organochlorine, organophosphorus and carbamate insecticides was examined in laboratory tests in Ontario. Field strains were collected from Gun Marsh, Michigan (1965, 1972), Grant, Michigan (1972) and Holland Marsh, Ontario (1972) and were compared to susceptible and cyclodiene-res'&nt laboratory strains. All field strains showed intermediate levels of resistance to aidrin, low but significant levels of resistance to DDT (1.7-2.4 x more resistant than the susceptible laboratory strain), the Ofganophosphorus insecticides parathion, ethion, dichlofenthion (VG13), fensutfothion, fonofos, chlorfenvinphos, diazinon, malathion and naled (1.46.5 x), and to the carbarnate carbofuran (3.0-6.2 x). The Gun Marsh strain was more resistant to organophophorus insecticides in 1972 than in 1965. In 1972, the Grant strain was generally the most resistant of the 3 strains to organophosphorus insecticides. Harrls, C. R., J. H. Tolman & H. J. Svec. 1982. Onlon maggot (Dlptera: Anthomyildae) resistance to some Insectlcldes followlng selection wlth parathlon or carbofuran. Canadian Entomologist 114: 681 485. A laboratory strain of Delia antiqua, with a low level (up to about 5-fold) of resistance to organopnosphorus insecticides, was selected in the laboratory in Ontario with parathion to determine if higher resistance levels to the selection agent and other insecticides used for control of the anthomyiid would result. Resistance to parathion increased to 10.1-fold after 4 generations of selection and to 23.8-fold after 14 generations. Without further selection, resistance declined by about 50% in 6-7 generations. Parathion resistance to ethion, diazinon, fonofos and carbofuran were 2-5 x as high as those measured initially. The pattern of resistance development in field strains in 1975 and 1980 was similar to that observed in the laboratory, but resistance levels were lower, probably because of lower selection pressure and the variety of compounds used under practical conditions. After 14 generations of parathion selection, reis&nce was 23.8-fold to parathion and 10.1-fold to carbofuran. After 12 additional generations of carbofuran selection, carbofuran resistance increased to 31.2-fold, while the level of parathion resistance remained the same. Hanis, C. R. & C. M. Tu. 1988. A description of the development and pathogenlclty of Entomophthora muscae (Cohn) In the onion maggot, Della antlqua (Melgen). Agriculture, Ecosystem, & Environment 20: 143-146. The development and pathogenicity of Entomophthora rnuscae from infected adult Delia antiqua, originally collected from Keswick Marsh, Ontario, are described. Morphological examination of the fungal growth, fruiting bodies and development of the disease is reported. Harrb, C. R. & S. A Turnbull. 1978. Laboratory studles on the contact toxlclty and acthity in sol1 of four pyrethroid Insectlcldes. Canadlan Entomologist 110: 285-288. The spectrum of contact toxicity and activity in soil of 4 pyrethroid insecticides on various insect orders was assessed in the laboratory. Contact toxicity was determined for Delia antiqua, in addition to honey bees (&is mellifera L.), adult Diabrotica longicomis (Say), nymphs of Gry//us pennsyIvanicus Bum. (Acheta pennsyhnicus) and larval Euxoa messoria (Harris). The cricket G. pennsykanjcus was used to assess insecticidal activity in soil relative to soil moisture, type and temperature. The compounds tested were permethrin (FMC 33297), WL 41706 (cyan0 (3- phenoxyphenyl) methyl 2, 2, 3, 3-tetramethylcyclopropanecarboxylate),WL 43467 (cyan0 (3- phenoxy-phenyl) methyl 3-(2, 2-dichloroethenyl)-2, 2-dimethylcyclopropanecarboxylate) and WL 43775 (cyano (3-phenoxyphenyl) methyl 4-chloro---(1 -methylethyl) benzeneacetate). Cholrpyrifos and carbofuran, 2 broad-spectrum contact and soil insecticides, were included for comparison. The pyrethroids were effective contact insecticides comparable in toxicity and spectrum of activrty to chlorpyriios and carbofuran, but were less effective in mineral soil than chlorpyrifos. WL 43467 showed activity in mineral soil comparable to that of carbofuran, while the other pyrethroids were less effective. Activity in soil was influenced by soil moisture md type. In contrast to the standard insecticides, the pyrethroids showed a negative temperature coefficient of toxicity in soil. Harris, C. R. & S. A. Turnbull. 1980. Toxlclty of some insecticides to Insectlckje- susceptible strains of the onlon, cabbage, and seedcorn maggots (Dlptera: Anthomylldae) and the darkslded cutworm (Lepldoptera: Noctuldae). Canadlan Entomologist 112: 1029- 1032. In laboratory investigations in Ontario on soil pests of crops, direct contact toxicity data were obtained with selected insecticides on adults of insecticides were highly toxic to D. antiqua (Meigen), the cabbage maggot, D. radicum (L.), the seedcorn maggot, 0. platvra Meigen, and larval Emmessoria (Harris). All insecticides were highly toxic to 0. antiqua, the descending order of toxicity being cypermethrin, chlorpyrifos, fenvalerate, permethrin, parathion, isofenphos and terbufos. Chlorfenvinphos was I.4 x as toxic as parathion to 0.radicum; the pyrethroids were less toxic, with fenvalerate 1/13 as toxic as parathion. The descending order of toxicity to 0. platura was diazinon, cypermethrin, chlorpyrifos, fenvalerate and permethrin. Against E. messoria, DOT and leptophos were 1/10 and 314 as toxic as chlorpyifos, while cypermethrin, fenvalerate, permethrin and decamethrin [(S)-cyano (Sphenoxyphenyl) methyl (1R-cis)-3-(2, 2- dibromoethenyl)-2,2-dimethylcycloprop~were about 10, 11, 12 and 120 x as toxic, respectively. Harrls, C. R., J. W. Whistlecraft, H. J. SV~C,J. H. Tolman & A. D. Tomlln. 1984. Outdoor rearlng technique tor mass production of onion maggots (Dlptera: Anthomylldae). Journal of Economic Entomology, 77:824-827. A technique is described in which large numbers of Delia antiqua are produced from outdoor, rearing-beds in southwestern Ontario. The technique proved suitable for production of up to 50,000 puparia per square meter of bed. A number of advantages to rearing outdoors are described however, occasional outbreaks of disease, probably microsporidian, greatly reduced longevrty and fecundity of adults when overcrowded. Hads, M. 0. 1987. Responses of ovlposltlng onion flies to authentic and surrogate onions. IN: insects-plants, Proceedings of the 6th lnternatlonal Symposlum on Insect- Plant Relatlonshlps, (PAU 1986) V. Labeyrie, G. Fabres, D. Lachalse (eds.) pg 392. Comparison of behavioural sequences leading to oviposition did not differ among female Delia entiqua exposed to onions at the 3-4 leaf stage and surrogates. Females on onions spent significantb more time examing the substrate and foliage with ovipositors than females on surrogates. Otherwise, no significant differences occurred in pre-ovipositional behaviours (grooming, running down foliage, proboscis extension, ovipositor probing, and insertion of ovipositor). Hanls, M. 0. 1987. Host-plant recognltlon In the onlon fly, Della antlqua (Melgen). Ph. D. Thesis, Mlchlgan State Unlverslty, USA Dlssertatlon Abstracts lnternatlonal, B (Sciences & Englneerlng) 47: 2746. Harrb, M. O., C. Chllcote & D. J. Howard. 1986. Electrophoretic studles of three Della species (Dlptera: Anthomylldae). Journal of the Kansas Entomological Soclety 59: 384 387. Anthomyiid vegetable pests of the genus Delia were examined in Michigan for 8 ewme systems, using horizontal starch gel electrophoresis. Delia antiqua (on Allium spp.) and the seedcorn maggot (D. platura Meigen ) (on very varied crops) were found to be more closely related to each other, with a Nei genetic distance of 0.398, than either was to the cabbage maggot D. radicum (L.) (on crucifers), with a genetic distance of 1.369 between D. antiqua and D. radicum and 0.9 between D. platura and D. radicum. These relationships confirm those suggested by morphological and cytological evidence and provide a framework in which to mwse the evolution of proximate mechanisms governing food- plant finding and acceptance behaviour. Hanls, M. O., J. E. Keller & J. R. Mlller. 1987. Responses to ndlpropyl dlsulflde by ovlposltlng onlon flies: effects of concentration and site of release. Journal of Chemlcal Ecology 13: 1261-1277. FemaleDelia antiqua laid the most eggs on ovipositional dishes having n-dipropyl disulfide (DPDS) release rates of 1-6 ng per s from polyethylene capsules placed beneath a sand substrate. When DPDS was released from the wax coating of surrogate foliage rather than from the substrate, ovipositing females again responded differentially to various concentrations, laying more eggs around stems containing 0.075 and 0.89 mg per stem. Factorial combinations of several concentrations released from surrogate foliage and substrate showed that releases from surrogate foliage stimulated 4 x more egg-laying than releases from the substrate. Females tended to lay more eggs around surrogate stems having DPDS at the base rather than on the upper hatf of the foliage. Observations of individual females performing preovipositional examining behaviours on DPDS-treated surrogate stems indicated that females tended to land on the upper portions of the foliage, but after landing, spent most of their time examining areas of soil and surrogate within 1 cm of the soil-surrogate interface. Surrogate stems provide a redistic context for investigating effects of plant chemicals on host-acceptance behaviours. Harrls, M. 0. & J.R. Mlller. 1982. SynerglSm of VISU~Iand chemlcal stlmull In the ovlpositlon behavlour of Della antlqua. Pudoc, Wagenlngen. pp. 117.122. The effects of visual and structural stimuli from surrogate onion stems (glass tubes containing coloured paper) on oviposition behaviour of Delia antiqua was assessed in laboratory studies. Tubes were comparable to onion stems when both were presented with chemical stimuli. When visual (yellow paper), structural (glass tubes) and chemical (chopped onion) stimuli were presented separately and in various combinations, treatments combining all 3 stimuli elicited about 80% of the total oviposition. As treatments containing either chemical stimuli or visuavstructural stimuli alone received only about 3% of the eggs, combinations of visual, stmural and chemical stimuli were considered to have a synergistic effect on oviposition. A synergistic effect was also observed when chemical and structural stimuli were combined, indicating that the onion stem provided not only requisite colour stimuli but also a stage for the performance of post-alighting preoviposition behaviours. Harris, M. 0. & J. R. Miller. 1983. Color stlmull and ovlposltlon behavlor of the onion fly, Della antlqua (Melgen) (Dlptera: Anthomylldae). Annals of the Entomological Soclety of Amerlca 76: 766-771. When presented with oviposition dishes containing a range of coloured surrogate onion stems, female Delia antiqua laid the most eggs around yellow stems. Response to yellow was elicited by hue and saturation, rather than brightness, and was reduced when either white or black was added to yellow. Differences in egg numbers on stirnulatory and nonstimulatory colours reflected differences in preoviposition behaviours. Alighting on sterns, stem walks, and probing with the ovipositor occurred more frequently on yellow than on blue or grey stems. The effect of yellow on post-alighting behaviours was independent of its effect on alighting. After alighting on a yellow stem, females performed 3 x more stem walks than on blue or gray stems and were twice as likely to probe with their ovipositors after a stem walk. Thus, colour is one of the diverse variables influencing alighting and post-alighting preoviposition behaviour. Harris, M. 0. & J. R. Mlller. 1984. Follar form InfluenceS ovlposltlonal behavlour of the onlon fly. Physlologlcal Entomology 9: 145-155. Female Delia antiqua laid the most eggs around narrow (4 mm) vertical cylinders when presented with dishes containing a range of surrogate foliar shapes. Oviposition response deminishd when stem diameter was increased or decreased, when cylinder height was reduced to <2 cm, and when cylinderlsubstrate angle deviated from 90 degrees. Differences in egg numbers were related to differences in post-alighting preovipositional behaviours. Females alighting on narrow vertical cylinders initiated and completed stem runs rapidly and without intenuptbns, and frequently went on to probe and oviposit. Females alighting on other shapes, or larger, smaller, or non-vertical cylinders, either did not initiate or did not complete stem runs, or did not go on to probe after completing a stem run. Such females rarely oviposited. Possible causes of such examining behaviours are discussed. Harris, M. 0. & J. R. Mlller. 1988. Host-acceptance behavlour in an herblvorous fly, Delia antlqua. Journal of Insect Physiology 34: 179-190. In this review of several experiments on ovipositional behaviours of Delia antiqua, no strong evidence for precedence of chemical stimuli in the sensory world of females was displayed. Although single host-plant chemicals are sufficientu stirnulatory to elicit oviposition in deprived females, the same can not be said for structural and colour cues from onion foliage. In undeprivd females, host colonization is most effectively stimulated by the integration of chemical and non-chemical subsets of the total stimulus pattern presented by onion plants. ~ost-plmtrecognition was investigated by presenting gravid females with surrogate plants and manipulating single surrogate features against a backdrop of unchanged stimuli. Colour, shape and size of surrogate foliage all influenced oviposition. N-dipropyl disufide (DPDS) with surrogate foliage stimulated 4 x more oviposition than a control substrate. Thus, placement as well as concentration of host plant chemicals affected ovipositional behaviour. Interactions among chemical and non-chemical stimuli were critical to the host-recognition process. Removal of a chemical stimulus or alteration of foliage colour or sue reduced numbers of eggs laid. Observations of females alighting on stirnulatory and n~n-~timulatorysurrogates indicated that colour, shape, size, and chemical stimuli influenced alighting and post-alighting behaviours. Running over surface foliage and ovipositor probing were most highly correlated with egg numbers. Effects of altering host-plant stimuli were also examined by quantifying egg production of individual females given a single surrogate type over an 8-d period. Elapsed times until 50% of the females accepted oviposition sites were about 7.5, 7.8, 8.8, and >13 d for control, chemical-, colour-, and size-akered surrogates, respectively. Control females distributed egg laying eventy over the experimental period, whereas females on altered substrates laid a significantly greater proportion of eggs 4 d into the experiment. This temporal concentration of egg laying coincided with maximal accumulation of mature eggs in the ovaries of deprived females. Harris, M. O., J.R. Mlller & O.M.B. de Pontl. 1987. Mechanisms of reslstance to onlon fly egg-laying. Entomologla Experlmentalk et Applicata 43: 279-286. When gravid female Delia antiqua were presented in laboratory choice tests with 6-wk-old plants of a susceptible cultivar and of onion breeding lines selected for resistance, mean numbers of eggs laid ranged from 34.8 to 1.6 eggs per plant. Differences in ovipositional responses were mirrored by differences in plant size. Anatysis of covariance revealed no significant differences in ovipositional responses in breeding lines when differences in sue were taken into account. Foliar surrogates were developed so that single size parameters could be varied while holding all other plant stimuli constant. Tests using these surrogates revealed that among plants with basal stem diameters of 1 to 4 mm and heights of 100 to 350 mm, diameter alone significantly influenced responses of ovipositing females. Ovipositional responses to plants beyond this size range could not be explained strictly by diameter differences. These results underscore the necessrty of considering plant size as well as plant chemistry and texture in efforts to evaluate and design resistant cukivars. Hassansada, M. K. & E. Naton. 1982. (R.10 effect of light Intensity and duration on the development of Phygadeuon trichops Thom. (Hym., Ichneumonldae).] Uber den Elnfluss der Uchtlntensltat und der Beleuchtungsdauer auf dle Enwlcklung von Phygadeuon ttlchopo Thom. (Hym., Ichneumonldae). Zeltschrlft fiir angewandte Entomotogle 93: 280- 284. The influence of light intensity and duration on the development of Phygadeuon trichops Thorns., a paradtoid of the puparia of Delia antiqua was studied in the laboratory in the German Federal Republic. The optimum lighting condition for rearing the parasitoid was under universal white light. Host puparia should be stored for about 2 d at 8:16 L:D and afterwards at 16:8 L:D. Under these conditions, very few mature larvae entered diapause. Hausmann, S. M. & J. R. Miller. 1989. O~lp~siti~naipreference and larval survlval of the onlon maggot (Dlpten: Anthomylldae) as Influenced by prevlous maggot feedlng. Journal of Economic Entomology 82: 426429. Ovipositional preference and subsequent larval survival of Delia antiqua on maturing onion bulbs with differing levels of larval infestation and microbial damage were determined in the laboratory. Oviposition preference was greatest on onions with low to moderate damage compared with healthy or severely damaged plants. Newly-hatched larvae successfully colonized go-100% of slightly or moderately damaged bulbs, but colonized only 15-20% of the severly damaged and healthy plants. Atthough weight gains for larvae reared on healthy or dightb damaged bulbs did not differ, gains for both groups were greater than for larvae reared on more severely damaged bulbs. Since overall hval survival was highest on slightly damaged bulbs, it was conduded that high densities of larvae found on recently-damagedfall onions, was a consequence of high oviposition preference and suitability of larval diet. Hausmann, S. M. & J. R. Miller. 1989. Productlon of onlon fly attractants and ovlposklonal atlmulants by bacterial Isolates cultured on onlon. Journal of Chemlcal Ecology, 15: 905- 918. The effects of compounds obtained by culturing Erwinia carotovora var. carotovora (EC) on sterile onion tissue, on attraction and oviposition behaviour of Delia antiqua was evaluation in laboratory choice tests. Results indicated that EC-inoculated onion was more attractive than Klebsiella pnuemoniae (KP) cultured on onion, EC cultured on potato, or n-dipropyl disulfide and an aqueous solution of 2-phenylethanol and pentanoic acid, used as chemical synthetic baits. Adults were mildly attracted to potato after inoculation with EC, but females did not accept EC- inoculated potato for oviposition. This work emphasizes that sources of semiochemicals may need to be defined microbiologically as well as physically and chemically. Havukkala, I. 1985. Soll partlcle slze preference on egg-laying onlon flies, Della antiqua (Dlptera: Anthomylldae), enhanced by host plant chemicals. Annales Entomologlcl Fennlci 51 : 62-63. Naive adult female Delia antiqua had only a slight particle-size preference when ovipositing in pure moist sand in the laboratory. The addition of a small piece of onion to the sand increased oviposition and enhanced a preference for coarse egg-laying substrates. This behaviour is discussed in relation to wiposition in sandy soils rather than heavy ones in the field. Havukkala, I. J. & J. R. Miller. 1987. Daily periodicity In the ovlposltional behavlor of the onlon fly, Della antlqua (Dlptera: Anthomylldae). Environmental Entomology 16: 41-44. Oviposjtion behaviour and the periodicity of oviposition under a 16:8 L:D photoperiod were examined for Delia antiqua in the laboratory. Preovipositional behaviours occurred in appreciable frequency throughout the day. However, most eggs were laid 10-12 h after the initial of photophase (1700-1900 h). Ovipositional periodicity appeared to be linked to photoperiod. It is suggested that the behavioural threshold for examining egg-laying sites may be lower than actual egg deposition. Atternately, experience gained while examining with minimum egg-laying might increase the efficiency of subsequent choices. Results confirmed earlier field obserations that fly activity is greatest from 1700 h until sunset. Heemert, C. van. 1973. Androgen-1% In the onlon fly Hylemya antlqua (Melgen) demonstrated with r chromosomal marker. Nature New Biology 246: 21-22. Heemert, C. van. 1974. Melotic dlsjunctlon, sex-determlnatlon and embryonic lethality In an x-llnked 'slmple' translocation of the onion fly, Hylemya antlqua (Melgen). Chromosoma 47: 45-60. Frequencies of different balanced and unbalanced chromosome sets to meitotic orientation and disjunction were examined in newly-emerged male Delia antiqua using a translocation, induced by a radiation dose of 1 kR. To test for the presence of translocations, single males were mated with 3 normal females, since single pair matings were only 10% successful. Resub indicated that small acrocentric chromosomes are sex-chromosomes, translocations are X- linked, and a XY (male) and XX (female) sex-determination system is present. Heemert, C. van. 1977. Somatk palrlng and melotlc nonrandom dlsjunctlon In a perlcentrk lnverslon of Hylemya antlqua (Melgen) [Della antlqua]. Chromosoma 59: 193- 206. Heemert, C. van. 1977. Synthesis of compound chromosomes from a perlcentrk lnverslon In the onlon fly Hylemya antlqua. Nature 266: 445-447. An attempt was made to isolate compound chromosomes using a pericentric inversion in Delia antiqua. Fwr different types of chromosome, of which two were regarded as compound, were produced if crossing occurred anywhere within the loop of a pericentric inversion heterozygote. Onb female D. antiqua are chiasmate, but crosses between inversion females and males with translocated chromosomes produced some progeny with the compound type of chromosome, consisting of a large recombinant chromosome from the female and a short complementary translocated chromosome from the male. Cytological analysis indicated that 16 different karotypes could occur, but of these 5 died as embryos and only 8 were observed among the embryos. Three of 40 larvae analysed had chromosomes of the male compound type, but no compound karotype was observed among 30 adult males and no strain with compound chromosomes was therefore isolated. Heemert, C. van, D. H. Ketel, J. J. F. Mulders W. J. van den Brlnk. 1979. Relatlonshlp between sex and development the In the onlon fly Hylemya antlqua (Melgen). Netherlands Journal of Zoology 29: 233-241. Sex differences in the development time of eggs, larval and puparia of 2 normal strains of Delia antiqua were detected from laboratory studies in The Netherlands. Rapidly developing puparia from rapidly developing larvae and eggs gave rise primarily to males. Distortion in the sex ratio was greatest in the development times of the pupal stage and least in the larval and egg stages. The distortion in each stage was independent of the distortion in the preceding stage and may allow for easier separation of males from females; especially in cases where males are sterlized for mass-release. Heemert, C. van & I. Wltteveen-Plllen. 1980. Location of the ADH gene in the onion fly using a translocatlon tester set. Journal of Heredity 71: 364-365. A method for locating the alcohol dehydrogenase gene in Delia antiqua, using a translocation tester, is described. Heemert, C. van & L. Vosselman. 1979. A male-linked translocatlon with hlgh fertility in the onlon fly Hylemya antlqua (Melgen). Genetlca 51 : 111-1 14. Using irradiation with fast neutrons, a male-linked translocation was isolated from Delia antiqua in The Netherlands. The translocation breakpoints in chromosome 2 and Y were in the vicinity of the centromeres. Predominantly anernate segregation occurred which explained the high level of fertility observed. The use of male-linked translocations for a genetic sexing method is discussed. Heemert, C. van & A. S. Roblnson. 1981. Cytogenetlc analysis and breakpoint dlstrlbutlon of radlatlon-Induced Interchanges In Hylemya antlqua Melgen. Genetlca 57: 154-160. OVW70 chromosomal rearrangements have been isolated in Delia antiqua with X-rays and fast neutrons, as determined by reduced fertility and ~ytologicalanalysis. Most rearrangements were asymmeMcaJreciprocal translocations, but triple and a single quadruple translocations were also observed. Two pericentric inversions were established. Both the meiotic and somatic pairing confjurations were used. In 7 of 42 asymmetric translocations, 'duplication' larvae were observed; these carried a large duplication and a small deficiency resulting in a significantty higher egg hatch. The presence of such karyotypes can be disadvantageous for the genetic contrd of pests of which it is the larvae that cause the damage. The largest number of breakpoints was established in chromosomes 2 and 6. It could be concluded from sibling crosses of reciprocal translocations in D. antiqua that homozygotes can be produced without the use of morphological markers. The cytological analysis of adults following the assessment of extra reduced fertility compared to the test-cross fertility is essential for the isolatioc of translocation homozygous individuals. Heemert, C. van & W.J. van den Brlnk. 1976. Location of an eye mutant In the onlon fly Hylemya antlqua Melgen uslng a perlcentrlc chromosome inversion. Experlentla 32: 1142- 1144. A mutation which occurred distally on the long arm in chromosome 3 of Delia antiqua resulted in the expression a white-eyed mutant. The value of such a mutation as a marker in research associated with genetic control is noted. Hennequin, J. 1970. [Evaluatlon of the levels of reslstance of the onlon fly (Hylemya antlqua Melg.) to organochlorlne Insectlcldes]. Appreclatlon des nlveaw de reslstance de I8 mouche de I'olgnon Hylemya antlgue Melg.) aux Insectlcldes organochlores. Ann. Zool. Ecd. Anlmale 2: 261 -279. Adult and larval Delia antiqua were exposed to levels of organochlorine insecticides to evaluate levels of resistance in populations from various regions in France. The level of resistance to aldrin, applied topically, among adult females ranged with locale from 35-653 x, respectively, from that of a susceptible laboratory strain. Levels of resistance were more accurately determined in the adults of a given population than in the larvae, even though resimce is acquired in the larval stage. Glasshouse studies indicated that trichloronate, chlorfmvinphos, dichlofenthion and carbophenothion were the most satisfactory replacements for organochlorine compounds. Hennequln, J. & Lacrolx, A. 1966. [Effectiveness and persistence of some active materials on larvae of the onlon fly reslstant to organochlorlnated lnsectlcldes]. Efflcacite et rernanence de quelques matleres actives our le~lanes de mouche de I'olgnon reslstantes rw Insectlcldes organochlores. Phytlat. -Phytopharm. 15: 277-282. Resistance of the insecticide aldrin by larval Delia antiqua has been reported from several areas of France, but not in the regions of Paris or Nantes. Nine compounds were tested as soil treatments with aldrin against susceptible and resistant strains of D. antiqua larvae in the laboratory from 1964 to 1966, in order to find an alternative insecticide that would remain effective for the 3.5 to 4 mo necessary to Protect ~nions.On average during the 3-yr period, the immediate and residual action of trichloronate, applied at a rate equivalent to 2.5 kg toxicant per ha, of chlorfenvinphos and carbophenothion, each at 6 kg, and of ethion (diethion) at 5 kg, gave good protection of the crop; 6-10 kg diazinon gave excellent immediate resutts and remained effective for 2.53.5 mo. Dimethoate, 3-methyl-4-dimethylarnin~methyleneiminophen~~ methylcarbarnate, and bromophos, applied at 7.5, 4.5 and 2 kg toxicant per ha, respectiveb, afforded good or moderate immediate control but had little residual action for practical use. Methidathion at 1.5 kg toxicant per ha was ineffective. Aldrin at 3-5 kg gave complete protection for at least 75 d only against susceptible larvae. Hemeldt, L., M. van Keymeulen & C. Pelerents. 1984. Large scale rearing of the entomophagous rove beetle Aleochara blllneata (Coleoptera: Staphyllnldae). Mittellungen, Blologloche Bundesanstalt fur Land-und Fortwlrtschatt, Berlln-Dahlem 218: 70-75. A method developed in Belgium for mass-rearing Aleochara bilineata Gylh., an important natural enemy of several dipterous pests of vegetables, using its natural host Delia antiqua is described. The average fecundity of females thus reared was 400 eggs per female. The yield of aduks averaged about 3540% of the number of eggs inoculated. Honda, I. & Y. Ishlkawa. 1987. Ultrastructures of the larval cephallc sensory organs of the onlon and seedcorn flles, Hylemya antlqua Melgen and H. platura Melgen (Dlptera: Anthomylldae). Applled Entomology & Zoology 22: 325334. The ultrastructures of the dorsal, anterior and ventral organs of larval Delia antiqua and the seedcorn maggot, 0. platura Meigen, are described from studies using scanning and transmission electron microscopy. No difference was found in the ultrastructures of these sensory organs between the 2 species. The dorsal organ consisted of 7 sensilla classified into 4 types. The dome part was considered to have an olfactory function, since the cuticle had many canal-like structures which connected the inside and the outside. The 3 sensilla between the dome and the socket were considered to be mechanosensory or gustatory. The functions of the other 3 sensilla, one in the invagination of the socket and 2 between the dome and the socket, were not clear. This organ was assumed to have mainly an olfactory function. The anterior organ consisted of 13 sensilla classified into 5 types. Among them, 10 sensilla of 3 types were considered to have a gustatory function. The functions of the other 3 sensilla were not clear. This organ was assumed to have mainly a gustatory function. The ventral organ consisted of 4 sensilk classified into 3 types. Two types were considered to be rnechanosensory. However the function of the remaining one was not clear. This sensory organ was considered to contain no chemosensillum. Honda, I. & Y. Ishlkawa. 1987. Electrophyslologlcal studies on the dorsal and anterior organs of the onlon fly larva, Hylemya antlqua Melgen (Dlptera: Anthomylldae). Applied Entomology & Zoology 22: 410-416. Electrophysiological experiments were conducted to confirm the functions of the dorsal and anterior organs of larval Delia art:lqua,which had been previously considered to be olfactory and gustatory in nature, based on tttitbr morphology. The dome of the dorsal organ, by its response to the onion compounds, n-dipropyl disulfide, and ethyl acetate, was proven to have an olfactory function. The anterior organ responded to 1 M solutions of various sugars and salts, and confirmed to have a gustatory function. Honda, I., Y. khlkawa & Y. Mabumto. 1983. Morphological Studles on the antenna1 sensllla of the onlon fly, Hykmya antiqua Melgen (Dlptera: Anthomylldae). Applled Entomology & Zoology 18: 170-181. Sensilla on the antennae of the male and female Delia antiqua were investigated using scanning and transmission electron microscopy. On the scape and the pedicel, onb mechanoreceptive sensilla were found, whereas on the surface of the funicle trichoid sensilla, basicmica sensilla, grooved sensilla, and clavate sensilla were found. All of these were considered to have an olfactory function. In large and small olfactory pits, olfactory sensilla of various types were detected. Distribution of sensilla is described as are differences in sensilla of males and females. Results are compared with other species of Diptera. Honda, I., Y. khlkawa & Y. Matsumto. 1987. Electrophyslologlcal studles on the antenna! olfactory cells of the onlon fly, Hylemya antlqua Melgen (Dlptera: Anthomylldae). Applied Entomology & Zoology 22: 417-423. Two types of antennal olfactory cells were identified from the surface of the funicle of mated, 7-21 d old female Delia antiqua. One cell responded well to n-dipropyl disutfide (DPDS) but little to ethyl acetate (EA), whereas the other cell responded to ethyl acetate but not DPDS. The DPDS cell responded to onion dour as well. Among the alkyl disulfides of alkyl chain length 1- 5, the DPDS cell showed high specificity to DPDS. Although both cells responded to n-alcohols, the DPDS cell was more responsive to heptanol and octanol, while the EA cell responded to pentand and hexand. Neither type responded to 2-phenylethanol or n-valeric acid. These cells contained basiconic sensilla. Hough, J. A, C, J. Eckenrode & G. E. Harman. 1982. Nonpathogenlc bacterla affecting ovlposltlon behavlor In the onlon fly. Envlronmental Entomology 11: 585-589. Female Delia antiqua laid more eggs on onion seedlings on which nonpathogenic bacteria rather than fungi predominate. When microbial mixtures were taken from healthy seedlings and tested on agar substrates, more eggs were laid on a medium containing ground frozen onions, which should contain larger amounts of sulfur compounds, than on a substrate made with nonfrozen onions. Of 16 bacterial isolates taken from seedlings, only Pseudomonas sp. was as stimulatory on the frozen-onion agar substrate as a mixture of microbes. A mixture of microorganisms taken from D. antiqua and inoculated on onion medium was as stimulatory as a microbial mixture taken from onion seedlings, suggesting that flies may help to disperse the bacteria they use as wiposition cues. Hough, J. A., G. E. Harmon & C. J. Eckenrode. 1981. Microbial stlmulatlon of onion maggot ovlposRlon. Envlronmental Entomology 10: 206-210. Female Delia antiqua laid fewer eggs on sterilized onion seedlings than on either untreated plants or on sterilized plants reinoculated with a mixture of microorganisms taken from heakhy seedlings. Reinoculation with Pseudomonas cepacia, a bacterium known to protect onion seedlings from certain fungal pathogens, did not enhance oviposition. Microbes grown on sterile agar media stimulated egg laying only if the substrate contained macerated onion tissue. Thus, microorganisms may metabolize chemical precursors in onions and convert them to volatile, stimulatory compounds. Hudon, M., P. Martel & C. Rltchot. 1980. [Status of the insect pests of certaln crop in south-western Quebec In 1978.1 Etat dm Insectes nulslbles dans certalnes cultures du du Quebec en 1978. Annals of the Ent~mol~gl~alSociety of Quebec 25: 68-71. Reports on the status of Severid insect pests in south-western Quebec indicated that populations of Delia antiqua remained the principal pest of onion in 1978. ~keshojl,T, 1984. S-propenylcystelne sulfoxlde In exudates of onion roots and possible decompartlmentallzatlon In root celk by bacterla Into attractant of the onion maggot, Hylemya antlqua (Dlptera: Anthomyildae). Applied Entomology & Zoology 19: 159-169. Levels of Spropenylcysteine sutfoxide (PCSO) in roots and exudates of aseptic onion seedlings, and total bacterial counts from roots of septic seedlings were higher in cultivars that were susceptible to larval Delia antiqua, than in resistant CU~N€KS.In addition, more propylthio oviposition attractants were generated in susceptible cultivars. In aseptic soil, where bacterial metabolism was impossible, PCSO accumulated. Of the PCSO extract produced in vitro from bacteria metabolism more methylthio compounds than propylthio compounds were detected. This was in direct contrast with the results of alliinase metabolism in chopped onions. Since intact onion seedlings, propagated in septic conditions, generated these compounds in intermediate proportions, it is suggested that both bacterial metabolism of exudates in soil and activation of alliinase by bacterial decompartmentization are simultaneoulsy taking place in the onion rhizosphere. Ikeshojl, T., Y. Ishlkawa & Y. Matsumoto. 1980. Attractants against the onion maggots and flies, Hylemya antique, In onlons Inoculated wlth bacterla. Journal of Pestlclde Sclence 5: 343-350. Laboratory experiments in Japan demonstrated that onions were more attractive to larval and adult Delia antiqua for feeding and oviposition, respectively, when larvae 1st infested and conditioned onions. A bacterium, Websiella sp., which was isolated from conditioned onions, appeared to be responsible for the generation of attractants. Slices of bacteria-inoculated onion, incubated for 3 d at 37"C, showed good attractancy. Following collection of headspace volatiles from bacteria-inoculated onion on Porapak traps, fractionation of constituents by liquid and gas chromatography, and mass spectroscopic anasis, results indicated that ethyl acetate, tetramethylpyrazine, n-heptanal, and 2-pentan01 were the major constituents, in addition to the well-known attractive sulfur-compounds n-dipropyl disulfide (DPDS) and methyl propyl disulfide. Bioassays of compounds singly, or in mixtures at various concentrations, demonstrated that ethyl acetate was the most attractive to larvae. The addition of tetramethylpyrazine and n-heptanal to DPDS tripled the attractancy of larvae. Addition of ethyl acetate and tetramethylpyrazine to DPDS also enhanced oviposition response by two to three fold. Addition of 2-pentanol to DPDS did not enhance the attraction of larvae or ovipositing females. Ikeshojl, T., Y. Ishlkawa & Y. Matsurnoto. 1981. Behavioral and EAG synergism of various compounds to dlpropyl dlsulflde in the ovlposltlonal attraction of the onlon fly, Hylemya antlqua Melgen (Dlptera: Anthomylldae). Applled Entomology & Zoology 16: 432-442. Twentyeight derivatives of n-dipropyl disulfide (DPDS) and ethyl acetate were screened for ovipositional attractancy and electroantennogram (EAG) responses of adult Delia antiqua. There was M, correlation between EAG response and ovipositional attractancy of compounds tested. Mixtures of ethanol, propanoh methyl acetate, dipropy1 ether, and propyl chloride, which r-mw the disulfide in physical and chemical characteristics, synergized DPDS at certain ratios. Resutts of EAG responses to these mixtures suggested that the synergistic effect of ethyl acetate was the resutt of perception on the same sensillum and receptor sites as DpDs. Propano1 was postulated to stimulate a separate sensillum because the EAG response to the mixture was additive. However, ternary mixtures of the synergistic compounds and the disulfide, did not yield any mactancy in spite of eliciting the highest EAG response. It was concluded that the EAG was not an adequate method for screening attractive compounds and their mixtures. Ikeshojl, T., Y. Matsumoto, M. Nagal, S. Komochl, M. Tsusuml & Y. Mitsu~. 1982. Correlation between the susceptlblllt~of onion CultIvarS to the onlon maggot, Hylemya antiqua Melgen (Dlptera: Anthomylldae), and the blochemlcal characterlstlcs of onion plant. Applled Entomology & Zoology 17: 507618. Conelations between the suceptibility levels of 23 cultivars of onions to infestation by larval De/h entiqua were investigated in the laboratory in Japan. In addition, various biochemical characteristics of onion seedlings were examined, following a scheme of the metabolic pathway of Spropenylcysteine suifoxide by chemical analysis and bioassay of metabolites. Onion seedlings of susceptible cultivars yielded a larger quantity of propylthio compounds and larval and ovipositional attractants than those of resistant cultivars. Alliinase activity was higher in susceptible cultivars. However, the level of Spropenylcysteine sulfoxide, the precursor of the attractants, was inversely proportional to the the rate of infestation, possibly due to its higher decomposition rate in the susceptible cultivar ~amplesduring transportation and storage. Hybrid F1 onion cultivars were more resistant to larval infestation due to less emanation of the attractants and lower alliinase than parent cuttivars. Ikeshojl, T., Y. lshlkawa & Y. Matsumoto. 1981. Ecologlcal and chemlcal Interactions between onlon and onion maggot, Hylemya antlqua (Dlptera: Anthomylldae). Review of Plant Protectlon Research 14: 141-148. The results of experiments to identrfy: 1) vulnernable phases of onion growth in relation to the life history of Delia antiqua; 2) differences in physical and chemical characteristics between resistant and susceptible onion cultivars; and 3) compounds which act as larval and oviposition attractants, are reviewed from laboratory and field studies conducted in Japan. Intact onions emanate alkykhio compounds which are oviposition attractants for D. antiqua females. Soil microbes, such as the bacterium Klebsiella sp., enhance attractancy by producing such non- sulphur compounds as ethyl acetate and ethanol. Onion cultivars which are resistant to 0. antiqua emanate smaller amounts of these attractants in the soil and air than susceptible cuttivars; hence fewer eggs are laid and fewer newly hatched larvae migrate to the onion roots. Of a large number of derivates of sulfur and non-sulfur containing compounds and binary mixtures screened for larval and ovipositional attractancy, a propylthio moiety was found to be essential for expressing attractancy. In addition, some non-sulfur analogues were quite synergistic to n-dipropyl disulfide. Ilovai, 2. & J. Tatar. 1983. (Populatlon changes of the onlon fly Delia antlqua Melg. and its environmental condltlons.] A kozonseg~ hagymalegy (Delia antlqua Melg.) populaclolnak valtozasa es kornyezetl osszetuggesel. Novenyvedelem 19: 310. lshlkawa, y. 1988. Electroantennogram r-ponses of the onlon fly, Hylemya antiqua Melgen (Dlpterr; Anthomylldae) to ovl~osltion~tlmulants. Applied Entomology & Zoology 23: 388-395. Compounds with a propytthio moiety elicited high electroantennogram (EAG) responses from gravid female Delia antiqua aged 94-25 d in a laboratory study conducted in Japan. The EAG responses for suhr compounds were similar to those obtained with single cell recordings from n- dipropyl disufide cells. Analysis of dose-EAG response regression lines for oviposition stimulants and related non-stimulants indicated that all oviposition stimulants were received by the same receptor. It was concluded that the specific oviposition stimulation of propylthio moeities can be explained in part by the specificity of olfactory receptors on the antennae. Ishlkawa, Y., K. Salto & Y. Matsumoto. 1988. Carbon dioxide explratlon rate of the onion fly, Hylemya antlqua Melgen (Dlptera: Anthomylldae) with reference to dlapause. Applied Entomology & Zoology 23: 199196. The possibility of discriminating between diapausing and nondiapausing puparia of Delia antiqua by measuring carbon dioxide expiration rates was investigated in the laboratory. The C02 expiration rate per unit body weight was highest in 2nd instars (8.0 p1 per mg per h) and continuousJy decreased until pupation. The expiration rate of non-diapausing puparia showed a typical U-shaped curve. The minimum and maximum of the curve were 0.3 and 1.0 PI per mg per h, respectively. The expiration rate of diapausing puparia showed a decrease for 7 d after pupation and then remained at approximatety 0.06 p1 per mg per h. Ishlkawa, Y., M. Yoshlda & E. Shlral. 1985. Color preference of the onlon fly, Hylemya antlqua Melgen (Dlptera: Anthomylldae) with reference to ultraviolet reflection. Applied Entomology & Zoology 1: 20-26. Cdwr preference of adult Delia antiqua was investigated with 18 sticky coloured traps in a field cage in Japan. A wide range of colours Was tested. Numbers of flies captured were compared with spectral reflectance (200-800 nm) of each colour. Preference of males oc females to coloured traps was not recorded. White traps with high reflectance in 400-800 nm, was the most attractive colour tested. White having high reflectance in 320-400 nm was significantty less attractive. Light blue (450 nm) and vivid yellow (572 nm) followed in attractiveness. Black and red had little attractance. The inhibitory effect of near ultraviolet reflection (320-400 nm) was first demonstrated in this study. Adults appeared to be attracted when either or both of blue or yellow receptors are stimulated, and this behavioural response is negated when UV light is stimulated at the same time. Since green leaves reflect yellow light most intensly, it is hypothesized that attraction to white may be related to the response to flowers and leaves since white contains all the spectral components which these reflect. Monitoring of flies may become more effective if an attractive CO~OU~such as light blue or white without UV relection, is employed. Ishikawa, Y., A Mochlzukl, T. lkeshojl & Y. Matsumoto. 1983. Mass-rearing of the onion and seedcorn flies, Hylemya antlqua and H. platurn (Dlptera: Anthomylldae) on an artlflclal dlet with antlblotlcs. Applled Entomology & Zoology 18: 62-69. A simple and inexpensive artificial diet was developed for mass-rearing Delia antiqua using a commercial food for guinea pigs, defatted soya flour, dehydrated yeast, sugar, agar, micro- nutrients and antibiotics with a large amount of cellulose powder added to improve physical quality. he advantages of the diet included: 1) no sterilization of eggs; 2) uniform growth of larvae; 3) high yield (65%); 4) pupal size comparable to those reared on onion; and 4) hygenic and relativeb odourless rearing conditions . Several antibiotics were screened, with neomycin- chloramphenicol being most cost-effective. Ishlkawa, Y., S. Tsukada & Y. Matsumoto. 1987. Effect of temperature and photoperlod on the larval development and dlapause lnductlon In the onlon fly, Hylemya antlqua Melgen (Dlptera: Anthomylldae). Applled Entomology & Zoology 22: 610- 616. Larval Delia antiqua were reared under several combinations of temperatures and photoperiods to determine the effect of these factors on larval development and diapause induction. The developmental zero temperature Was little affected by photoperiod (4.3"C under 16-8 L:D, 46•‹C under 12-12 L:D), Whereas total effective temperature necessary for development was greater under short photoperiod (278 day-degrees). When maintained at 25•‹C and 16-8 L:D, most flies emerged 9-18 d after pupation, but some emerged 40-60 d later. The temperature inducing diapause in 50% of individuals was found to be significantly affected by photoperiod; 14•‹Cunder 16-8 L:D, and 18.S•‹C under 12-12 L:D. Ishlkawa, Y., T. Ikeshojl, Y. Matsumoto, M. Tsutsuml & Y. Mltsul. 1983. 2-phenylethanol: an attractant for the onlon and seed-corn flies, Hylemya antlqua and H. platura (Dlptera: Anthomylidae). Applied Entomology & Zoology 18: 270-277. Chemical analysis of aged onion pulp indicated that 2-phenylethanol was a potent field attractant for adult Delia antiqua and the seedcorn maggot, D. platura Meigen. The attractive compoun& in the aged onion pulp were found to move into the acidic and neutral fraction, following fihration, steam-distillation, and extraction with ether. Analysis of the neutral fraction by GC and GGMS revealed the presence of iso-butyl alcohol, ethanol, ethyl acetate, iso-amyl alcohol, and 2 phenylethanol, the last two compounds being the major constituents. Only 2- phenykthad showed moderate attractancy to D. antiqua in a laboratory bioassay, but showed high attractancy in the field. The attractancy was comparable to fresh onion pulp, which had about ban the attractancy of aged onion pulp. Attractancy to 0.platura, especially males, was quite high. No significant sex difference in attractancy of adult 0.antiqua to 2-phenylethanol was observed. Ishlkawa, Y. & T. Kubota. 1991. Effect of host plants and dietary quercetln on antloxldant enzymes In onlon and seed- corn maggots, Della antlqua and D. platura (Dlptera: Anthomylldae). Applled Entomology & Zoology 26: 245-253. The effect of host plants and quercetin on the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPOX), from Delia antiqua and the seedcorn maggot, D. piaura Meigen, was studied. The SOD activity in the latter species was 1.7 x that of the formet when both were reared on a synthetic diet with no plant secondary compounds. The SOD activities of the 2 species when feeding on their respective host plants (Allium cepa (onions) and soyabean) were 100-230% greater than those of larvae feeding on the synthetic diet. Synthetic diet contained up to 0.1% quercetin, a prooxidant chemical present in onion bulbs, elicited m, increase in SOD activity, although SOD increased -2.5 x in both species when the concentration was 1.0%. CAT levels were very high and were unaffected in both species by the diet or the addition of quercetin. A strong inhibition of GPOX was observed in larvae reared on onion and the synthetic diet containing 0.1% quercetin. ~shlb~,y., T. Ikeshoji & Y. Matsumoto. 1981. Field trapping of the onlon and seed-corn flies with balts of fresh and aged onion pulp. Applied Entomology & Zoology 16: 490-493. The field attractiveness of fresh, and aged onion pulps and n-dipropyl disulfide (DPDS), an attractant and oviposition stimulant to adult Delia antiqua in laboratory tests, was compared in two experiments in Japan. Plastic cyhjer traps, replicated 9 or 16 x, were placed at 10 m intervals in a 3x3 or 4x4 Latin square design in an onion field. Onion pulp, 150 g per trap, or DPDS, at 1.2 ml per 25 ml liquid paraffin, were placed in each trap. A control treatment consisted on 25 ml of water alone. In one experiment, treatments consisted of fresh onion, aged onion (over the course of experiment), and water. In the other DPDS was tested with the other three treatments. Traps were set at 1200 h and flies captured were counted every 2 h until 1800 h and from the interval from 1000 to 1000 h the next day. Aged onion pulp was more attractive to adult D. antiqua than other treatments. Both fresh and aged onion attracted both sexes, whereas DPDS attracted predominantly females. This suggested that onion pulp was a feeding lure and DPDS acts as an oviposition lure. Onion pulp appeared to increase in attractiveness with age, notably 2 d. However, cod weather and near constant rainfall may have confounded theresub. No clear peaks in fly capture per h were evident nor were large numbers of 0. antiqua caught with DPDS. This latter effect is contradictory to studies in North America were DPDS has proven to be an effective bait. Difference in strains is offered as an explaination, but the ptesence of strong attractants besides the propytthio moeities in the onion pulp is also suggested. I8hlkawa, Y., T. lkeehojl Y. Matsumto. 1978. A propylthio molety essential to the ovlpositlon attractant and stimulant of the onlon fly, Hylemya antiqua Meigen. Applied Entomology & Zoology 13: 115-122. Trapping onion volatiles by Porapak Q column and GC-MS analysis revealed 9alkyl di- and trisulfides. Among these, dimethyl, methyl propyl and dipropyl trisulfides were newly identified in the headspace onion odour. The latter two were found, for the first time, to have attractant and oviposition-stimulating activrty. From bioassays of 24 synthetic and commercialty available compounds, it was concluded that a propylthio moiety is essential for a compound to express activity. These findings were discussed in relation to host plant sektion of Delia antiqua and synergism among the onion odour components. Ishlkawa, Y., Y. Matsumto, M. Tsutsuml, Y. Mitsui, K. Yamashl, Y. Mamoru & E. Shlral. 1987. Controlled release formulatlon of attractant for the onion and seedcorn flies, Hylemya antiqua and H. pletura. Applled Entomology & Zoology 22: 303-309. Z-phenylethand in a water solution was replicated 16 X. Flies were marked with felt pen and released at 7-8 d of age (295 and 413 males and females, respectively) at the centre of the onion field. Flies were recovered from traps at daily intervals. Population parameters were estimated using the Zi index method. Traps placed in onion fields caught more flies than the periphery which contrasts other studies. It was suggested that the onion field may serve as an aggregation and mating site. Since females require honey or protein to develop ovaries and no food sources were found in the onion field, possible forage sites outside of the onion field include several wild flowers, i.e. Lysimachia sp. (loose-trife), Taraxacum officinale (dandelion), Trifolium pretense (red clover), Heracleum lanatum (hogweed), Solidago altissima (goldenrod), Capsella bursa-pastoris (shepard's purse) and Syringa wlgaris (lilac). Females provided these food sources in the laboratory oviposited normally. Ishlkawa, Y., Y. Matsumoto, M. Tsutsuml & Y. Mltsul. 1984. Mixture of 2-phenylethanol and n-valerk acid, a new attractant for the onion and seedcorn flles, Hylemya ant/gua and H. platum (Diptern: Anthomylldae). Applied Entomology & Zoology 19: 448-455. Onion pulp was subjected to filtration, steam distillation, and fractionation to neutral, acidic ad basic fractions. Attractants were located in both acidic and neutral fractions. While 2- phenylethanol is a major component of the neutral fraction, the acidic fraction was heretofore untested. Among six simple organic acids (acetic, proprionic, n-butyric, iso-butyric, iso-valeric), n-valeric acid mixed with 2-phenylethaml, 0.05% and 0.02%, respectively, in 50 ml of water was significantly more attractive in capturing adult Delia antiqua than decomposing onion pulp by a factw of 1.8 to 5. Acids were tested singly with water and onion pulp as controls in 5x5 Latin square experiments undertaken within an onion field over a 1-3 d test period. Atthough few adults, of both sexes, were recovered from traps, a synergism between 2-phenylethanol ad valeric acid was evident. Jabbar, A S. & T. A. Al-Darkady. 1985. [Blologlcal studies of onlon fly Della (=Hy/emya) antlqua (Mg.) (Dlptera: Anthomylldae) on different onlon varletles.]. Journal of Agriculture & Water Resources Research 4: 161-173. The biology of Delia antiqua was studied under field and laboratory conditions in Iraq, where the anthomyiid is considered as an important pest of onion but has not been well studied. The egg stage lasted 5.6 d in the field, 3.5 d in the laboratory at 20•‹C and 2.36 d in the laboratory at 25•‹C. On 5 onion varieties used for rearing, no significant differences were observed in larval development and adult longevity after oviposition, but significant varietal differences were observed in duration of the pupal stage and preoviposition and oviposition periods. The largest number of eggs per female were laid on the variety Egyptian Geza and the smallest on Egyptian Buharee. In the laboratory, the duration of the larval and pupal stages and the preoviposition and oviposition periods were all significantly affected by temperature. Jager, A [On the mode of actlon and posslblllties of Use of Mlnaclde, a new carbarnate Insecticide]. Uber die Wlrk~fIgsweISe und Elnsatzmogllchkelten von Mlnaclde, einem neuen Carbamat-lnsektlzld. 19: 188-193. he insecticide 3-methyl-5-isopropylphenyl methylcarbarnate (Minacide, Schering 34615 or Carbamuk) proved effective in laboratory and field tests against a wide range of insects, including Delia antiqua, when poured on or applied to furrows. In a 2-choice bioassay using a control onion treated with hexane and an onion treated with hex- and pine oil, female Delia antiqua preferentially chose to oviposit near the control onion. Given no-choice, females laid 3 x as many eggs On the solvent control onions as on onions treated with 1% pine oil. A 50% detterent concentration was calculated to be 0.09% pine oil. Judd, G. J. R. & J. H. Borden. 1988. Long-range host-flndlng behavlour of the onion fly Della antlqua (Dlptera: Anthomylldae): ecological and physlologlcal constraints. Journal of Applled Ecology 25: 829-845. The effects of sex, age, mating and habitat on the long-range, olfactory, host-finding behaviour of Delia antiqua were examined in a field study conducted in British Columbia. Males and females responded to onion volatiles over distances Up to 100 m. Significantly more males were recaptured on white sticky traps baited with n-dipropyl disulfide (DPDS) than females. Virgin adults, of both sexes exhibited random dispersal independent of habitat. Dispersal of Delia antiqua in the absence of host odour was random with respect to wind direction. Recapture of virgin and mated females, 7 and 6.1%, respectively, were not significantly different. Rates of recapture of males remained low until males were 4-d-old, after which recapture increased linearly. A positive anemotactic response in males apparently increased with age. Males and females at 10-14 d moved upwind in response to DPDS, independent of habitat. About 50% of mated females were recaptured 25 m from the release point. Host-finding of males and females appeared to depend on similar olfactory stimuli. Following a period of maturation, males and females engaged in positive memotaxis upon exposure to DPDS. In males this occurred at 46 d and in females at -7-9 d. Mating caused a significant reduction in the proclivity for long-range, upwind directed movement in females. It is postulated that long-range orientation involves positive anemotaxis in response to host-plant-producedalkyl disulfides. Judd, G. J. R. & J. H. Borden. 1989. Distant 0lfaCtorY response of the onlon fly, Della antlqua, to host-plant odour in the field. Physiological Entomology 14: 429-441. Distant olfactory orientation of adult female Delia antiqua to n-dipropyl disulfide (DPDS) was examined in the field using mark-release-recapture experiments and observations of flight behaviour. Onion-reared, postdiapause, virgin females from a laboratory strain dispersed upwind Wnrelesased in the centre of 25, 50 and 100 m radius circles of eight 50 pI DPDS baits. Percentage recapture and direction of dispersal did nd decrease as a function of increasing distance to baits, and mean flight direction of recaptured flies was positiveb conelated with mean wind direction. However, modes of the circular distributions of recaptured flies were located further crosswind when odour-baits were more distant. When distance was held constant (25m) and DPDS concentration serially reduced (500-0.5 pi per bait), flies drspersed randomb in the absence of DPDS, crosswind in response to 0.05 pl baits, and upwind in response to all other baits. Percentage recaptures on DPDS-baited traps of all concentrations were significantb greater than on unbaited tr%. Observations of flight beh4our downwind -&orated resuns from mark-recapture studies. Flies located 100 m downwind from 50 p1 DPDS baits flew upwind on take off, while take-off flights in the absence of DPDS were random. Data indicated that D. antiqua orientated to host plants using long-range olfactory cues. A//ium volatiles like DpDS are involved not only in the acceptance phase of host selection, but also in the first stage of host-finding when females are initiating search long distances downwind. . judd, G. J. R. & J. H. Borden. 1991. Sensory lnteractlon during trap-flndlng by female onion flies: Implications for ovlposltlonal host-plant flndlng. Entomologla Experlmentalls a Appllcata 58: 239-249. Using various three-dimensional traps alone and in combination with onion volatile, n-dipropy1 disulfide (DPDS), visual behaviour of female Delia antiqua was found to vary with the badground composition and trap spacing (visual context) in which traps were presented. Visual behaviour also was affected by reproductive status. Given a choice of green or white-coloured spheres and cylinders against a backdrop of onion, females alighted more frequently on white spheres. Against a background of bare soil, females oriented to DPDS baits more frequently on vertical than horizontal surfaces, but size and spectral reflectance were insignificant. Mated females alighted more frequently on green than white cylinders, but unmated females responded to cylinders independent of spectral reflectance. Response to traps mimicking onion plants suggested that ovipositional host-finding was dominated by olfactory responses at long range (several metres) and by visual cues at short-range (about 1 m). Judd, G. J. R. & J. H. Borden. 1992. Aggregated ovlposltlon In Della antlgua (Melgen): a case for medlatlon by semlochemlcals. Journal of Chemlcal Ecology 18: 621 -635. Experiments conducted in the laboratory tested the hypotheses that aggregated oviposition by female Delia antiqua was invoked by stimuli associated with ovipositing females, newly laid eggs, or bdh. Using a paired oviposition bioassay that eliminated visual stimuli associated with the treatment under study, 67% of the eggs laid by caged females were in response to the dour of females alrea* ovipositing on an onion slice, as opposed to 33% of the eggs laid in response to an onion slice alone. When newly laid eggs were transferred to onion slices and held for either 24 or 48 h before being bioassayed against similarly aged untreated onions, 74% and 97% of the eggs were laid at the egg-treated onion stations, respectively. Similar results were achieved when an aqueous wash of newly laid eggs was applied to the onion slice. When the egg wash was processed through a bacterial filter or when eggs were present but not in contact with onions, all response was eliminated. These results implicate microorganisms transmitted on the egg surface in creating an attraction for ovipositing females. Heptane extracts of ovipositor tips from mated, ovipositing females induced 72% of the test females to oviposit near points at which extracts were applied to the oviposition station floor. A behavioural sequence for an optimal host-selection strategy is hypothesized, whereby host-seeking females respond to host- derived alkyl sulfifides at long range and metabolic by-products of microbially infested hosts and visual cues at short range (-1 m), with final sele~tionof ovi~ositionsites potentially reinforced by contact with and aggregation pheromone released or left on the substrate by owpositing females. ~udd,a. J. R. & J. H. Borden. 1992. Influence of different habltats and matlng on olfactory behavior of onion fllem seeking ovlposltlonal hosts. Journal of Chemical Ecology 18: 605- 620. effects of different habitats and mating on the olfactory behaviour of female Delia antiqua of a bboratory-reared and wild strain to traps baited with natural and synthetic onion volatiles, was examined in a field trial in British Columbia. Rankings of olfactory treatments as host- finding stimuli for females were dependent On their mating status and the habitat in which they were foraging. In habitats devoid of hosts, traps baited with individual alkyl sulfides were as effective as r)-d-old chopped onions and more effective than 1-d-old onions in eliciting host- finding behaviour in laboratory-reared unmated f€males (LUF) and laboratorty-reared mated females (LMF). However, upwind dispersal and percent recapture were always significantly greater in LUF. In one experiment, n-di~ro~~ldisulfide Was 19 x more attractive to LMF in a fallow field, as than it was in an onion field. Reduced effectiveness of alkyl sulfides as hm- finding stimuli in onion fields probably results in Part because they are less findable, but more importantly because of a change in searching behaviour after females have mated. Evidence to support the latter contention is that traps baited with alkyl sutfides and onions were equally findable by unmated females in both habitats. The behaviour of LMF was identical to that of wild females, &reas the behaviour of LUF was identical to wild males. The hypothesis that olfactory host-finding behaviour in D. antiqua is modified by the resource level was upheld. ~lkyl sutfides appear to be the primary, and possibly the only, chemical effectors of host-finding at the patch level of resource distribution, whereas the complex blend emitted by aged, chopped, or damaged onions appears to be acting at the final level of host-finding, while egg-laying females are moving between adjacent hosts in search of an optimal oviposition site. Judd, G. J. R., J. H. Borden & A. D. Wynne. 1988. Visual behavlour of the onlon fly, Delia antiqua antagonlstlc Interaction of ultraviolet and vlslble wavelength reflectance. Entomologla Experlmentalls et Appllcata 49: 221 -234. The interaction of ultraviolet (UV = 350-400 nm) and visible (400-650 nm) in the visual behaviour of adult Delia antiqua was examined by measuring spontaneous alightment on various UV and non-UV-relecting, sticky cardboard traps in onion fields. Alightment on traps was negatively correlated with the percent UV (350 nm) and green (540-580 nm) reflectance and positively correlated with the percent blue (430-470 nm) reflectance. Alightment varied directly with the ratio of 'stimulatory/inhibitory' reflected wavelengths. Males and females were similar in their response to both UV and visible wavelength relectance, with the exception that males were more sensitive than females to UV-reflecting white surfaces. A multiple regression model, that used the intensity of 3 key wavelengths, 350, 450, and 560 nm, as independent variables, explained 90% of the variation in the combined male and female response to spectral reflectance from traps. These results indicate that some visual behaviours are a function of the integration of sensory input from the entire spectral distribution of the stimulus, and not simply the dominant wavelengths or hue. Kagan, F. 1978. (The characterlstlcs of development, appearance and noxlousness of the more Important pests of vegetable plants In Poland In 1976.1 Charakterystyka rozwoju, nasllenla wystepowanle I szkodllwoscl waznlejszych szkodnlkow roslln warrywnych w Polsce w roku 1976. Biuletln Instytutu Ochrony Roslln 62: 251-289. In a survey of insect damage to horticuttural crops in Poland conducted in 1976, damage by larval Delia antiqua to onions was -6% due to effective application of seed dressing. Kagan, F. & Studzinskl, A. 1968. [Studies on the effectiveness of dleldrln preparatlons for the control of the onlon fly (Hylemyla (Delia) antlqua Melg.) and the determination of dleldrln retsldues In the scales of onlons by a blologlcal method.] Badanh skutecznoscl prepamtow dleldrynowych w wake ze smletka cebulanka (Hylernyla (Delia) antlqua Melg.) omz o~acmnlepozostaloscl dleldryny w luskach cebull blologlczna. Prace Naukowe Instytutu Ochrony Roslln 10: 237-243. and in mid April in 1965. When seedlings were dipped in a slurry containing Smietkol at 5, 2.5 and 1.25 g per litre, Alvit 55 at 5 g per litre or DDT at 200 g per litre before planting out, infestation percentages averaged 12.6, 12.1, 24, 10.1 and 20.7, respectively, as compared with 57.5. ~arvalAedes aegypti (L.) were used in a bioassay to determine the persistence of residues in the outer scales of onions grown from seed treated with Smietkol at 50, 25 and 12.5 g, 55 at 50 g or DDT at 200 g toxicant per ha, respectively. Residues averaged 0.29, 0.25, 0.1 3, 0.37 and 0.16 p.p.m., respectively, as compared with 0 for no treatment, and were not significant. Kagan, K. 1977. [Characterlstlcs of the development, Intensity of appearance and InJurlousness of some maln pests of vegetable plants In Poland In 1974.1 Charakterystyka romoju, nasllenia wystepowanla I szkod~~wosclwaznlejszych szkodnlkow roslln warrywnych w Polcse w roku 1974. Bluletyn Instytutu Ochrony Roslln, 60: 287-323. Among several insect pests of vegetable crops in Poland, notes are provided on the pest status of Delia antiqua on onion in 1974. braman, G. A,F. M. Khalll & A. H. El-Sebae. 1973. Prellmlnary studles on the biology of the onlon fly, Hylemyla antlqua Melg. (Dlptera: Muscldae). Bulletln de la Seclete Entomologlque dlEgypte 56: 429-435. The bionomics of Delia EvItiqUa, a serious pest of onion in Egypt, was investigated in the laboratory. Adults were provided with a diet consisted of a mixture of honey, dried pollen grains and Brewers' yeast food, and larvae were reared on onion. In each of three generations, reared from June to October, the preoviposition period averaged 10.8, 7.5 and 14.6 d for each generation, respectively, and females laid up to 63 eggs each. Eggs were laid in groups of 3-6, directb on bulbs or nearby soil, and hatched in 2-3, 1-2 and 3-4 d in the three generations, respectively. The larval stage lasted 13-19, 21 -26 and 19-23 d and the pupal stage 9-12, 13-16 and 22-26 d, respectively for each generation. Overall, each subsequent generation required 30- 35, 42-48 and 43-50 d to complete development from egg to adult, respectively. Keller, J. E. & J. R. Mlller. 1990. Onlon fly ovlposltlon as Influenced by roll temperature. Entornologla Experlmentalls et Appllcata 54: 3742. Laboratory tri& in Michigan indicated that acceptance of ovipositional substrates by female Delia antiqua was determined, in part, by substrate temperature. Surrogate onions were employed with an apparatus which controlled soil temperatures at 5, 15, 22, 30, 35, and 400~ and air temperatures at 15 or 22•‹C. Most eggs were laid at the 22•‹C substrate. Air temperature of 30•‹C appeared to be near the upper limit of oviposition. Optimum temperature for oviposition corresponded well with the temperature optimum for egg survival and development. Ketel, D. H. & C. van Heemert. 1979. Mating assessment of the onlon fly Hylemya antlqua Melgen and the house fly Muss domestlce L. using (32)P. lnternatlonal Journal of Applled Radlatlon & Isotop~30: 651. In a survey of Diptera attacking vegetable crops in the Marmara region, the following were recwded: Hylemya cilicmra Rond., as a pest of onion, garlic, leek, squash, cucumber, melon, water-melon, spinach and radish, and producing three generations annually, Delia antiqua as a pest of onion and leek, and producing four generations a year, Psila rosae (F.), on carrot and celery and Muscina assirnilis L. on leek. In this area Dipterous pests of vegetable crops have been injurious in years of hot and rainy weather, especially where farmyard manure is used, but in dry years damage does not reach economic level. Kllmaszewskl, J. & R. R. Blume. 1986. New host records for Aleochara verna Say and Aleochan Verne Say and AIeochara n0tula Erlchson (Coleoptera: Staphyllnldae, Aleocharlnae). Coleopterest's Bulletin 40: 32. From observations in Texas in 1984, Aleochara vem4 a staphylinid that has been reported parasitizing Delia antiqua, the cabbage maggot, Delia radicum (L.), 0.planipalpis (Stein), and the seedcorn maggot, 0.platura Meigen is recorded for the first time parasitizing Paregle cinerella. The staphylinid A. notula Erichson is recorded parasitizing P. cinerella and 4 other species of Diptera for the first time. Kmmer, J. p. 1971. Experimental studies On the phycomycosls of muscold flles caused by Entomophthora muscae (Cohn). Journal of the New York Entomological Soclety 79: 52-55. The fungus Entomophthora muscae (Cohn) Was succe~~f~llytransmitted from infected Delia antiqua to Lucilia (Phaenicia) cuprina (Wied.) and vice versa. Further attempts at transmission were unsuccessful. ~ubom,T. & Y. bhlkawe. 1990. Blochemlcal properties of a glutathlone Sttansfemse from the onion fly, Hylemya sntlqua Melgen (Dlptera: Anthomylldae). Applled Entomology & Zoology 25: 375-382. One of several glutathione Stransferases, important in the detoxification of insecticides, purified to apparent homogenety and characterized from Delia antiqua. The purified enzyme showed functionality to glutathione conjugation, bilirubin and haematin binding, and glutathione peroxidase activity. Kurpp, S. 1989. Pests of cultivated plants In Finland during 1988. Annales Agrlcuhurae Fennlae 28: 97-102. ResuRs of a questionnaire conducted to survey several insect pests on agricultural crops in Finland indicated that Delia antiqua caused extensive damage to onion in 1988; partialb in response to weather conditions amenable to infestations. Uu, H. J., F. L. McEwen & G. Rltcey. 1982. Forecasting events In the life cycle of the onion maggot, Hylemya antlqua (Dlptem: Anthomylidae): appllcatlon to control schemes. Envlronmental Entomology 11: 751-755- Field monitoring adult eclosion and peak activity, ovarian development, oviposition periods, and larval damage of Delia antiqua on onion fields in Ontario, confirmed that a scheme of predictions of life cycle events based on day-degree accumulations was a reliable method to determine spray application of insecticide. Recommendations based on this method allowed a number of growers to reduce spray treatments from 7-12 to an average of 2 during the growing season and to achieve excellent control. Loosjes, M. 1976. Ecology and genetic control of the onion fly, Della anltqua (Melgen). 1976. Agrlcultural Research Report No. 857, Pudoc, Wagenhen 179 pp. years, was provided. A program for The Netherlands required an estimated mass-rearing output of 1.5 x (1019competitive fly equivalents. Luckman, W. H., G. Gangrade 81 D. B- h~~~ma.1967. Inducing sterility In the onion maggot. Journal of Economic Entomology 60: 737- 741. In laboratory tests in which virgin adult Delia antiqua were fed on a diet of dry milk and sugar with 0.14% aphdate or hempa (hexamethylphosphoric triamide), the former was the most effective in reducing egg viabilw. When the concentrations were ~0.5%, some degree of fertility was regained if the adults were removed from the treated diet after 48 d. In large-cage tests conducted in a glasshouse in which onion plants were growing, there was almost complete sterility *en half or all of the feeding trays were treated with 1% hempa or 0.5-2% apholate. Treatment with chemosterilants was more effective in reducing infestation of the onions than diazinon applied in granules to the furrows at a rate of 0.45 kg per 13,400m of row. Enzymatic yeast hydrobsate was incorporated in ne8Ily all the diets to increase their attractiveness to adults. Madder, D. J. 1981. Pest management In muck crops In the Holland marshes. IN: Proceedings of the Twenty-Eighth Annual Meeting, Canadlan Pest Management Soclew, St. Catherlnee, Ontarlo, August 7- 12,1981 Canada; Canadlan Pest Management Soclew, pest and disease management on carrot and onion in an area of 3,850 ha of the Holland marshes, Ontario, is briefly described. Delia antiqua, noctuids and thrips were monitored on onion and for treatments were based on previous damage and cropping history, day-degree models and peaks in adult activity. Growers on the program reduced their treatments against pest insects by 30-1ME6- Mahleu, N. & D. Grill. 1973. [The protection of market3arden crops in the Nantes reglo".] L. protection des cunures maralcheres dans la reglon Nantalse. Phytoma 25: 17-25. Msrkkula, M. & S. Kurpp. 1985. Resistance of hsedS and mites to pestlcldes In Finland. Annales Agrlculturae Fennlae 24: 161-174. Insecticides and acaricides used in Finland since 1945 and pest resistance to 20 of 69 toxicants used is reviewed. Resistance to at least 1 compound has been found in Delia antiqua among several other species across a diverse range of taxa. These results are discussed in relation to the control of household pests and pests in the field and the glasshouse, including biological control of glasshouse pests. Mamhall, S. A & M. Eymann. 1982. Mlcroorganlsms as food for the onlon maggot, Della (= Hflemya) antiqua (Dlptera: Anthomylldae). Proceedings of the Entomologlcal Society of Ontarlo 112: 1-5. From scanning electron micrographs of' pharyngeal ridges in larval Delia antiqua, it is suggested that the larvae are microbe grazers. Larvae Were reared on onion either sterilized or inoculated with bacteria, and the results obtained indicated that bacteria or their products play a major role in the development and survival of the larvae. Martel, P. & J. Daneau. 1973. Evaluation of furrow applied granular Insectlcldes for the control of the onlon maggot, Hylemya antiqua (Melg.), In southwestern Quebec. Phytoprotectlon 54: 51-56. Martin, J. S. 1981. Mating behavlour of the onion maggot fly Hylemya antlqua Melgen In laboratory condltlons. M. Sc. thesis, Unlve=lty of Guelph, Guelph, Ontarlo 43 pp. Using single pair mating trials and a whfie-e~e,genetic marker to examine the mating frequency of fernaleDelia antiqua, demonstrated that females mated only once. Males mated several times, the frequency of mating in Cage experiments being positively related to increased numbers of females in cages. Additional information on the mating frequency, fecundity, and fertility in single pair matings, duration of reproductive period, postcopulatory influence of males on females, and mating behaviour, from a limited number of observations, are described. Martln, J. S. & F. L. McEwen. 1982. Frequency of matlng In the onlon maggot, Hylemya antiqua (Dlpten: Anthomylldae). Canadlan Entomologist 114: 647-648. Female Delia antiqua mate only once, males mate repeatedly. These results were confirmed by experiments in which 10-d-old white-eyed mutant males and females were confined in pairs with a suitable oviposition media and egg hatch Was determined. When hatch occurred, mutant males were replaced with red-eyed males. Following the addition of red-eyed males, no re- mating occured since no red-eyed adults were produced. Seventeen percent of females laid eggs following single-paired matings. Martinson, T. E., J. P. Nyrop & C. J. Eckenrode. 1988. Dispersal of the onlon fly (Dlptera: Anthomyildae) and lawal damage in rotated 0nl0n flelds. Journal of Economic Entomology 81 : 508-514. Adult Delia antiqua, trapped in water pan traps in nonhost vegetation throughout a 740-ha muck, were captured in large numbers up to 1.5 km from overwintering sites in May and June during the 1st flight. Few flies were captured in nonhost areas during the 2nd flight in J~IY. Similar, high levels of onion maggot damage Were observed in 10 small onion plots planted in organic soils at locations varying from 0.4 to 1.5 km from overwintering sites. Damage in untreated plots in commercial fields nd planted to onions the previous year was related to distance from overwintering sites (fields plants to onions the previ0~~year), and declined with increasing distance. Lowest damage levels, comparable to damage measured in chlorpyrifos- treated research plots, were located in small, isolated mucks that had been planted to another crop the previous growing season. me dispersal properties of adult Delia antiqua were examined in field studies in New York State. Factors investigated included: 1) directionality of movement of adults in the presence and absence of host plants against diverse backgrounds of vegetation, and 2), age and mating status of feral females, trapped in host and non host habitats. Recaptures of males were distributed randomb in non host backgrounds and directionally in host vegetation, either downwind or upwind of the release point. In nonhost environments, recaptures of females were randomly distributed regardless of mating status. Recaptures of males were often significant4 directional but not conelated with wind direction. Ovarian development and mating status of flies recaptured in nonhost vegetation 1.2 km from the I'Iearest onion field or overwintering site with no host plants were similar to those trapped in an onion field. Flies trapped at an overwintering site with no host plants were, on average, Younger and less likely to be mated. Assuming flies did not disperse from onion fields, there Was evidence of mating outside of onion fields. Overall, results suggest that long-range directed movement has little influence on the probabiltiy or extent of colonization of new onion fields. Mabumoto, Y. & A. J. Thorstelnson. 1967. A slmple method for rearing the onlon maggot, Hylemya antiqua Melgen (Dlptera: Anthom~lldae)in the laboratory. Applied Entomology & Zoology 2: 5859. An improved method for rearing Delia antiqua in the laboratory was described. Adults were kept at 25-30•‹C under fluorescent light for 16 h Per d and supplied with a mixture of evaporated milk, sugar and water on a cotton pad, renewed thrice weekly. Brewers' yeast was sprinkled on foMed paper towels inserted into flasks of Water and also renewed at intervals to prevent drying. ~ggswere laid in moistened coarse sand in glass containers each containing a portion of an onion and separated from the sand by Rotation. Over 500 eggs were obtained per d from a cage containing 50-150 females. Onion powder Can be used instead of onion sections; this avoids the necessity of washing the eggs if they or newly hatched larvae are needed for experiment. For hatching, which occurs after two d, the eggs are placed on sand containing onion halves. After 20 d, the puparia are floated out and placed on moistened vermiculite. Puparia are formed 10- 14 d after egg inoculation, but do not float when young. More than 90% of the adults emerge in 10-14 d. Oviposition by female Delia antiqua was significantb greater on sand treated with methanol solutions of organic sulphur compounds or water solutions of carbonyl compounds or alcohols than untreated sand in laboratory bioassays. Females laid the most eggs on sand treated with 0.001 -0.2 ml n-propyl mercaptan or 0.0005-0.001 ml n-propyl disulphide (DPDS), constituents of onion juice. Oviposition was not significantb increased by higher concentrations of the 2nd compound or by most of the other compounds tested and it was inhibited by many of them, Mixing the two effective chemicals with alcohols or acetone improved the results only in the case of DPDS mixed with n-propyl alcohol. In dishes covered with a mesh screen, attractive chemicals induced landings and probing with mouth-pafts and ovipositor, respectively, but no actual oviposition. Matsumoto, Y. & A. J. Thorstein~on. 1968. Olfactory response of larvae of the onion maggot, Hylemya antlqua Melgen (Diptern: Anthomyildae) to organic sulfur compounds. Applled Entomology & Zoology 3: 107-1 11. McClanahan, R. J. 1966. A synwetlc diet for the onion maggot, Hylemya antlqua (Melgen) (Dlptera: ~~thomylldae).Canadlan Journal of Zoology 44: 1089-1090. When irradiated with 3 kR within five d of pupal formation, puparia of Delia antiqua did not complete development. Older puparia were not adversely affected. Females from treated puparia were sterile and laid no eggs when caged with normal males. Males from treated puparia were sterilized to a high degree, but sm~males had viable sperm and inseminated normal females (0.2%). A 6:1 ratio of sterile to normal flies reduced egg hatch to 1.7%. Females did not mate before ovaries had developed; however the stage of development was not noted. The relationship between age and sexual receptivity for male and female Delia antiqua, and factors affecting ovarian development were examined in small and large bioassay arenas. Small arenas had a significant negative effect On genesis over the first 10 d of adult life and, in some cases, on the percentage of females inseminated. The rate of ovarian development was not affected by male population density, but high densw of females appeared to have a priming affect. McEwen, F. L., G. Rltcey & H. J. Liu. 1984. Labomtory studles of radiation-induced sterility on the onlon maggot, Della antiqua (Diptern: Anthomylldae). Canadlan Entomologlst 116: 119-122. Mclean, J. A, I. G. Stump, J. M. D'Aurla dl J. Holman. 1979. Monltorlng trace elemento in diets and life stages of the onion maggot, Hylemya antiqua (Dlptera: Anthomyiidae), with X-my energy spectrometry. Canadlan Entomologist 111 : 1293.1 298. MI^^, J, R. w., C. R. Harris & P. Moy. 1978. Insecticide resldues In organlc so11 of the Holland Marsh, Ontarlo, Canada, 1972-75. Journal of Economlc Entomology 71: 97-101. Miller, J. R. & R. S. Cowles. 1991. Stimulodeterrent dlverslon: a concept and Its possible appllcatlon to onlon maggot control. Journal of Chemlcal Ecology 16: 3197-3212. Research conducted on the host-colonization response of Delia antiqua to A//ium cepa demonstrated that ovipositional behaviour is the s~mmationof sensory information derived from various chemical, visual, and physical modalities encountered during resource examining, not from a simple set of readions to a few chemical stimuli. A three-tier, across-modalrty stimulus summation model is presented which suggests that an integration of peripheral receptors of several modalites (tier I),their associated sensory interneurons (tier 2), and a central command motor interneuron (tier 3) are reC&Iired to stimulate muscle associated with egg deposition. Understanding and manipulating physiological and behavioural activity of insects in response to chemical stimuli requires an approach that is less reductionist than testing chemicals alone. Bi0-y~ should include positive controls which provide accompaning non-chemical stimulii, to overcome the possibility of a deficient behavioural context. Mlller, J. R., M. 0. Harrls & J. A. Breznak. 1984. Search for potent attractants of onion files. Journal of Chernlcal Ecology 10: 1477-1488. A comparisjon of the mechanisms of oogenesis and the influence of environmental factors on fecundity, in addition to a brief description of female gonads, were investigated on Delia antiqua, the cabbage maggot, D. radicum (L.1 and Pegom~iabetae Curt.. All species contained meroistic polytrophic ovarioles, of 30 to 40 ovariob possessing cyclic activity. Follicle growth proceeded Mlssonnler, J. & E. Brunel. 1972. [mmparatjve study of the biology of two strains of Hy/emy/a milqua Melg., one susceptible and the other rtimlstant to organo-halogenated Insectlcldes.] Etude comparative de la blologle de deux souches d' Hylemyla antiqua Melg., loune sensible et loautre reslstante aux prodults lnsectlcldes organo-halogenes. Annales de Zoologle, Ecologie Anlmale, 4: 83-95. Control of strains of Delia antiqua resistant to organa-halogenated compounds were continued with 11 different insecticides on onion fields in six localities in northem France in 1965. soil treatments, 5.4 Ib. carbophenothion, 3.2 kg diazinon, 2.0 kg ethion (diethion), 1.0 kg s 4400 (0 ethyl 0-2,4,5-trichlorophenylethylphosphonothioate) or 2.4 kg chlorfenvinphos (SD 7859) per 2.4 ha gave the best protection, and 0.6 kg gamma BHC (lindane) was also effective. ~~houghpupal sexing in cyclorrhaphous flies is complicated by the lack of morphological differences in the sclerotization of the integument of mature larvae, a method is described to sex puparia. Visual examination of puparia at 10 d of the total of 12 d required for pupation (23•‹C) indicated a difference in the distribution of hair On the abdominal tergites of pharate adults. In females, hairs on the abdomen are uniformly distributed and at a higher density than males. ~ochlzukl,A., Y. bhlkawa & Y. Matsumoto. 1985. Sugars as phagostlmulants for larvae of the onion fly, Hylemya antlqua Melgen (Dlptera: Anthomylldae). Applled Entomology & Zoology 20: 465-469. Phagodimulants for larval Delia antiqua Were isolated from onion bulbs. Among the basic, acid and neutral fractions of the rnethanolic extract, only the neutral fraction showed phagostimulatory activity. This fraction contained glucose, fructose and sucrose at 0.09, 0.07 and 0.06 M, respectively. Fructose and sucrose were effective at 0.1 M, but glucose was not effective at any concentration. The mixture of these sugars at 0.05 M each was also effective. Fructose and sucrose in onion bulbs were determined to act additivety as phagostimulants additively to larvae, suggesting the importance of the fructose moiety. Mochlzukl, A., Y. lshlkawa & Y. Matsumoto. 1989. Factors on Intra-host preference of the larvae of the onion fly, Hyiemya anti~a(Dl~tera: Anthomylldae). Applied Entomology & Zoology, 24: 36-41. Mochhukl, A., Y. lshlkawa & Y. Matsumoto. 1989. Olfactory response of the larvae of the onion fly, Hylemya antlqua Melgen (Dlptera: Anthomylldae) to volatile compounds. Applled Entomology & Z00log~24: 29-35 Larvae and aduks of of the muscid Coenosia tigrim are predaceous on earthworms and adults of Delia antiqua, respectively. In the laboratory, adult female lifespan was nearly 2 mo at 250~. Oviposition began 1-3 wk after eclosion, and females laid eggs in batches averaging 10-30 eggs at intervals of from 1 to several d. Fecundity reached an average of 230 eggs at 25•‹C with the sustained ptesence of males. Females exhibited maximal daily predation at 25"C, but maximal lifetime predation at 20•‹C. Male predation Was bwer than females. The duration of the egg stage varied from 5 d at 25•‹C to 11 d at 15•‹C. On 4 Species of lumbricids as prey, larval development occupied from 12-28 d. Larval su~ivalWas 30-60% On worm sections, 17% on live mature Eisenia foetidal and 90% on live immature E. foetida 1-2 cm long. Larval C. tigrina penetrated the epidermis of earthworms, and fed internally with a preference for circulatory and chlorogogenous tissues. Morris, D. E. & K. A. Plvnlck. 1991. Earthworm mucus stimulates ovlposltlon 1" a predatory fly (Dipten: Anthomylldae). Journal of Chemlcal Ecology 17:2045-2052 Female Delia antiqua preferred to ovi~ositon sprouted bulb onions than on seedlings given a choice in glasshouse bioassays, reinforcing the use of sprouted bulbs as an oviposfiional trap crop. However, larval mover'nent away from potentially impenetrable, undamaged bulbs to aggregations on susceptible seedlings is a consideration and placement of trap crops relative to Mowry, T. M., J. L. Spencer, J. E. Keller J. R. Miller. 1989. Onlon fly (Della antlqua) egg deposltlonal behavlour: plnpointlng host acceptance by an Insect herblvore. Journal of Insect Physiology 35: 331359. Mowry, T. M., J. E. Keller & J. R. Miller. 1989. OvIposltlon of Della antlqua (Dlptera: Anthomylldae) as Influenced by Substrate holes and Partkle slze. Annals of the Entomological Soclety of Amerlca 82: 126-131. Methods of mass-rearing of Phygadeuon trichops Thorns., a parasitoid of Delia antiqua and several other Delia spp., and susceptibility to 39 insecticides or acaricides, 27 fungicides and 9 herbicides were evaluated in laboratory and field-simulated tests in the German Federal Republic bout 50% of compounds were toxic in laboratory and semi-field tests. Results with p. trichops, with those obtained with other beneficial insects,were used to demonstrate the necessity for subjecting candidate insecticides to both laboratory and semi-field tests against natural enemies before using them for practical control in the field. Nlemczyk, H. D. 1965. The response of Hylemya antlqua adults to hydrolyized proteins and other materials: r laboratory study. Journal of Economlc Entomology 58: 425428. Nlemczyk, H. D. & G. Prlns. 1965. Contact toxlclty of 13 lnsectlcldes to cyclodlene- susceptible and cyclodlene- resistant strains of the onion maggot. Journal of Economic Entomology 58: 1074-1076. Chemical compounds for the control of Delia antiqua on chives were evaluated in field trials conducted in Denmark in 1970. Results of field tests with fungicides and insecticides against pests of agricultural and other fieM crops, including Delia antiqua on onion are reported from Denmark, in 1971 . Park, C. G., J.S. Hyun, B.K. Chung 81 M.H. Lee. 1991. [Development of the onlon maggot, (Della antlqua) (Dlptera; Anthomylldae), Pupae In relation to temperatures and pupation times.]. Research Reports of the Rural Development Admlnlstratlon, Crop Protection 33: 5440. me effects of various ecological factors on populations of Delia antiqua were examined in experimental onion plots in south-western Quebec in 196470. Soil type was the most imprtant factor regulating the egg laying capacity of females in a given field. Cultivars of A//ium cepa were more attractive oviposition sites than those of A. fistulos~m,and both the condition and stage of development of the plant influenced the pattern of infestation. Seeding rate or plant densrty did not influence the ovipositing females, although high plant densny favoured parasite populations and increased the rate of pupal mortality of 0. antiqua. An increase in plant density also appeared to result in lower populations of larvae and decreased mortality of the seedlings even though the number of eggs laid Per plant varied little at different seeding sites. Fluctuations in the populations of parasites paralleled those of D. antiqua, but only after a delay of approximateb two wk, indicating that eggs and early larvae of the 1st generation may almost entjreb escape mortality caused by such natural enemies. Popra~kl,T. J., P. H. Robert, I. Majchrowlcz G. Bobin. 1985. Su~ceptlblllt~of &/la antiqua (Diptern: ~nthomylldae)to eleven Isolates of entomopathogenlc hyphomycetes. Environmental Entomology 14: 551-561- Rawllns, W. A. & D. Gonzales. 1966. Evaluation of Several insectlcldes to control the onion maggot. Journal of Economlc Entomology 59: 288-290. Rawllns, W. A. & Lodge, M. 1966. insectary evaluation of new Insectlcldes for onion maggot control. Journal of Economic Entomology 59: 299-303. ~ltchot,c., G. RIOUX, M. A. Richard, M. Gulbord, G. Lamontagne, J. M. Beausolell C. Morln. 1973. me prlnclpal insects of economk Importance In Quebec In 1972.1 Prlnclpaux Insect- du Importance economlque au Quebec en 1972. Annals of the Entomological Society of Quebec 18: 7-9. Robinson, A. S. & G. Zurllnl. 1981. Mating success of differently shed onion flies, Delia ant/qua. Entomologla Experlmentalls et Appllcata 30: 101-105. R~S,K. 1. A 1992. Comparative study of the antenna1 sensllla of flve species of root maggob: Della radlcum L., D. floralls F., D. antlqua Mg., D. platura ~g.(Diptern: Anthomyildae) and Pslla rosae F. (Diptent: Psllldae). Journal of Insect Morphology & Embryology 21 :l75-197. Saynor, M. & D. S. Hill. 1977. Chemical control of onion fly, Della antlqua. Annals of Applled Biology 85: 113- 120. SchneJder, W. D., J. R. Miller, J. A Bremak & J- F. Fob-. 1983. Onion maggot, Della rntlqua, rurvlval and development on onions In the Presence and absence of mlcroorganlom~.Entomologh Experlmentalis et A~~llcata33: 50-56. Sonl, S. K., R. E. Baldwln & P. R. E1llsi. 1986. Evaluation of onlon cultivars for rearing onion fly In the laboratory. Annals of Applied Biology (Supplement) 108: 172-173. Stoffolano, J. G. Jr. 1969. Nematode parashes of the face fly and the onion maggot In France and Denmark. Journal of Economlc Entomology 62: 792-795. Sub, S. J. & y. J. Kwon. 1990. Morphometrlc multlvarlate classlflcatlon of Della ant/qua and D. platura from Korea (Dlptera: Anthomylldae). lnsecta Koreana 7: 1-37. S;~cmpmka,K. 1960. (The results of one lnvestigatlons of the effectiveness of the actlon of organophosph~i'O~Sand cmbmWe Vtkum against the onion fly (Hy/emYa anthua Melg.) .] Wynl kl Jednorocznego doswladczenla nad s kutecznoscla dzlalania wtycydow fosforoorganlcznych I karbrmlnlanowch pmlwko srnietce cebuJance (Hykmya antiqua Melg.). Biuletyn IflStY'tutuOchronY Rmlin 45: 213-219. investigated. Included in this booklet on the production and marketing of onions is a section devoted to the control of the major pests, including Delia antiqua, aphids, and thrips. Teng, X. Q. & Z. C. He. 1989. [investigation On blonomlcs of onlon fly.]. Journal of Shenyang Agricultural Unlvemfty 20: 89-94. The labelling of germinal and ~omaticcell types in young male adult Delia antiqua with tritiated thymidine (3H-thymidine) revealed the temporal Pattern of spermatogenesis. Labelling of cells in the female reproductive organs, which is also described, showed a far less distinct panern of oogenesis. The nuclei of fat cells, mid-gut epithelium, accessory glands and muscles, and occasionally the haemocytes, all retain whactive isotopes. In oenocytes and Malpighian tubules, trajated thymidine is incorporated into the cytoplasm. Methods have been developed of producing Delia antiqua on a large scale. Larvae were reared on a synthetic diet containing carrot powder and Brewers' yeast as the main ingredients. Larvae developed under constant temperature (25"C), humidity (75%), and light. Mating was reported to take place after 1 wk hen the eggs were well developed. In addition, presence of the host plant was reported to provide an oflactory stimulus for ovarian development. Some data on influence of cold storage to hatching of puparia is also presented in addition to a life cycle depiction at differing temperatures. The effectiveness of ppthrins Was compared with that of malathion and isofenphos for the control of 6 insect pests of vegetable crops in 2 tests in vegetable gardens in Finland in 1976-77. In a test against Delia antiqua on onion, 3 applications of 0.1% pyrethrins at the beginning of the growing season afforded about as good Protection as treatment with isofenphos, and lasted throughout the summer. Delia antiqua is the most important insect pest of onion in Ontario. Some problems hindering the implementation of an effective integrated pest management program for its control on the Thetford Marsh were identified. Steps taken to overcome such problems are outlined, including effective management of cull onions, implementation of an effective pest monitoring system and the identification of the 2 parasites Aphaereta pallipes (Say) and Aleochara bilineata Gylh. The resuRs of preliminary releases of A. pallipes are described. Tolman, J. H., D .G. R. McLeod C. R. Harris. 1986. Weld losses In potatoes, onions and rutabagas In Southwestern Ontarlo, Canada- the case for pest control. Crop Protection 5: 227-237. Tolman, J. H., J. W. Whistlecraft & C. R. Harris. 1985. Della ant~qua.IN: Handbook of Insect rearing. II, P. Slngh & R. F. Moore (eds.) Elsevler, Amsterdam pp. 49-57. A method is described for the continuous rearing of life Stages of Delia antiqua on sliced onions in controlled environment rooms or cabinets. In addition, date on several aspects of the life cycle are provided including development time, effect of temperature on survival, development, and egg production. At 2O0C, eggs hatch in 3.1 d, larvae develop over 15.5 d, and adults emerge from puparia after 12.2 d. TO attract ~ocalparasites and predators, miniature (1m2 ) mass-rearing beds containing life of Delia antiqua were established at three commercial onion-growing fields and an experimental farm in south-western Ontario in 1980-81. Puparia of D. antiqua from each of the three generations were collected from the beds before adult eclosion and allowed to complete development in the laboratory, enabling collection and identification of emerging parasites. Seven insect species (3 staphylinids and 4 hymenopterans) were confirmed as parasites, of which only the braconid Aphaereta ~alli~esand the staphylinid Aleochara bilineata were significant mortality agents (parasitism rates being UP to 17 and 20.7%, respectively). Twenty Tomlln, A. D. & J. J. Mlller. 1982. 'Dauero' stage nematodes phoretlc upon several arthropod species. Proceedlags of the Entomological Soclety of Ontarlo 112: 41-43. Small quadrats of sliced onions that were used as an attractant for adult Delia antiqua in onion fields in Ontario in 1979-80 also caught third-stage 'dauero' larvae of a species of nematode which were phoretic upon a nitidulid, a ceratopogonid and two species of mites. Toms, A M. & J. A. Blackett. 1983. The use and potential of seed coatings. IN: 10th International Congress of Plant Pr~te~tl~n1983 2: 523-524. This discussion on the use and potential of seed coatings against pests and diseases includes notes on the control of Delia antiqua on onion and Psila rosae (F.) on carrot. Tsutsuml, M. & Y. Mltsul. 1985. [The seasonal Prevalence of three specks of Dlptera on onion in Sapporo Dlstrlct.]. Annual Report of the Soclety of Plant Protectlon ot ~orth Japan 33: 119-121. Tsutsuml, M. & Y. Mltsul. 1987. [Effects of halts on survlval and development of ovary of onion fly (Hy/emy/a antlqua).] Annual Report of the Society of Plant Protectlon of North Japan 38: 146-148. me differences in susceptibility of onion varieties to feeding by larval Delia antiqua were investigated in a glasshouse study in Japan by releasing reared adults on seedlings. TU, C. M. & C. R. Harris. 1988. A d-criptlon of the developments and pathogenicity of Entomophora muscae (Cohn) in the onon maggot, Della 8ntlqu8 (Melgen). AgrlcuRure, Ecosystems & Envlronment 20: 143-146. Turnbull, S. A. & C. R. Harris. 1986. Influence of Posttreatment temperature on the contact tox)clty of ten organophosphorouS and pyrethrold lnsecticldes to onlon maggot adults (Dlptera: Anthomylldae). Proceedings of the Entomological Society of Ontario 117: 41-44. Va~okowkaya,E. 1. 1978. [Induction of pupal dlapause In the onlon fly Hylemyla antiqua ~g.(Dlptera: Anthomylldae).]. Trudy Zoologclheskogo lnstltuta 69: 1141 23. The effects of temperature and constant daylength on diapause or the continuance of activity was examined in three local populations of Delia antiqua in the former Soviet Union. A population from Kishinev in Moldavia showed an increase in individuals in the active state when the daylength in the shortday range was gradually increased up to the threshold. The critical daylength for this population was between 14 and 15 h. (t was hypothesized that adult Delia antiqua would show high preference in the field for trap cokurs reflecting visible wavelenghts between 400 and 480 nm at reflective intensities above 37%. This preferred spectral zone (PS4 was tested in an onion field in 1984, using cardboard traps painted with 11 blue, violet, and green hues, and two PSZ relecting colours of varying intensity. Colours with peak reflective intensw, were most preferred. Wavelength-specific reflectance intensity was shown for the first time under field conditions to influence the magnitude of cdour preference in the onion fly. The attraction of adult Delia antiqua to cardboard traps painted with 48 chromatic and achromatic hues was examined in an onion field in British Columbia. A white standard was mays among the most attractive colours tested. With respect to hue, violet and blue were as attractive as white and significantly more attractive than saturated hues with peak wavelengths between 480 and 700 nm. Yellow was not an attractive hue. Any saturated or unsaturated cobur that relected wavelengths between 350 and 480 nm at an intensity greater than or equal to that of violet were as attractive as white. It is suggested that attractiveness of colours to onion flies in the field is determined by CO~OU~,hue or by saturation, and that the magnitude of a response elicited by hue or saturation is determined by the intensity of attractive key wavelengths, Brightness itself is not a determinant of attraction. White was determined to be the best colour for use in a monitoring program. In all studies more males were consistently caught on all trap colours, but no sexual preferences were observed.. This may reflect the actual field sex ratio or indicate that males are more active or responsive to colour than females. is suggested that females fly nearer to the ground than males, and as a consequence will more frequentty miss elevated traps. Precise data on a sequential basis were collected for longevity, duration and interval of oviposition, fecundity, and oviposfiion periodicity for female Delia antiqua reared individualb under lab~atoryconditions. Some females were alive and ovipositing after 66 d, whereas males generally did not sutvive past 50 d. Ovi~ositionoccurred 8 d post-eclosion. Egg production was greatest between 10 and 30 d and cyclical. Heavy oviposition occurred once every 2 d. Mean fecundity for individual females was 491.5 (range 319-8411 eggs, about 2 x greater than females in culture. Females between ages of 10 and 15 d are suitable for oviposition bioassays and fairly consistent oviposition should be expected for 30 d post onset. Since a 48 h oviposition rhythmn war evident, females should be depiwed of test odour stimuli for at least 24 h prior to testing. Duration of experiments could be 1 or 3 d with 10-15 females per replicate, since he*hy females can be expected to lay 40eggs at 1 and 3 d, given the proper stimuli. me dispersal ability of laboratory-reared adult Delia antiqua was examined from a mark- release-recapture experiment conducted in British Columbia. Marked adults aged 6-7 d (termed sexualb mature) dispersed slowb when released in a 0.8 ha onion field. Of 2,956 aduhs released, 38% were recaptured (overall 2.5% males, 26.6% females) within 6 d on yellow sticky traps baited with lacerated whole onions. Results indicated that properly precondfiioned laboratory-reared adults can be effectively used in bait preference studies in the field. Vernon, R. S., J. H. Borden, H. D. Pierce, Jr. 81 A- C. Oehlschlager. 1977. Host selection by Hylemya antlqucr: laboratory bioassay and methods of obtalnlng host volatiles. Journal of Chemical Ecology 3: 359-368. Vernon, R. S., J. W. Hall, G. J. R. Judd 81 D. L- Bartel. 1989. Improved monitoring program for Della ent/qua (Dlptera: Anthomylldae). Journal of Economic Entomology, 82: 251-258. Vernon, R. S., G. J. R. Judd, J. H. Borden, H. 0. Pierce, Jr. & A. C. Oehlschlager. 1981. Attraction of Hylemya antlgua (Melgen) (Diptern: Anthomylldae) in the fleid to host. produced ovlposltlon stlmulanto and their nonhost analog~es.Canadlan Journal of Zoology 59: 872-881. Single pair matings of Delia antiqua were used to examine sex chromosome polymorphism. Resuns are also presented from group matings (10:10 ma1es:females) held for 1-2 d at an age of 10-14 d. Sex determination in D. antiqua employs a strongly male 'dominant yw system, with x and Y chromosomes in adults occuring in two forms each, XL and XS, and y1 and y2. The ratio of females to males Was generally 1:I. However, some crosses produced an excess of either males or females which was attributed to somatic numerical variation in chromosome ~2.Progenies with an excess of males came from males with testes with a relatively higher number of cells with 2Y2S and progenies with an excess number of females cam from males with testes mainly consisting of cells with 0 and 1 Y2. The occurrence of gynandromorphs supported the idea that in insects no circulating sex hormones are present. Vosselman, L. 1979. Sex determlnatlon of the onhfly, Hylemya antlqua (Melgen). 11. Sex ratio dlstortlon by unstable somatic behavlour of chromosome Y2 and Inheritance of a nonfunctional Y2 (Ym). Chromosoma 75: 353-367. Vosselman, L. 1981. Fitness of a translocation homoz~goteIn cage experiments with the onion fly, HyIemya antlqua (Melgen). Theoretical & Applied Geneth 58: 79-85. Vosselrnan, L. & C. van Heemert. 1980. Melotlc dlsjunctlon and embryonic lethality in sex- linked double-translocation heterozYgous males of the onlon fly, Hylemya antique (Melgen). Theoretical & Applled Genetlcs 58: 161- 167. Meiotic disjuction and embryonic lethalrt~in sex-linked double translocation heterozygous (~14fl61) male Delia antiqua was examined with the aim of producing a method of genetic control. is demonstrated that such males were potentially suitable for the development of a genetic sexing system. The application possibilities of the material for genetic control of D. antiqua were discussed. Wells, A. L. 41 M. L. Lacy. 1968. Control of onion maggot and smut wlth insecticide- funglclde formulations. Quarterly Bulletin of the Mlchlgan State Unlverstty Agrlcuhuml Experimental Statlon 50: 423-429. surrogates. Surrogate colour had no effect on fecundity. Flies deprived of exposure to DPDS took longer to initiate oviposition and to complete ovipositional cycles. The presence of untreated surrogates increased the percentage of eggs laid in ovipositional cups from 1474%, whereas the presence of DPDS Or host-plant CO~OU~resulted in neaiiy all the eggs being laid in cups. The number of eggs retained at death did not differ among treatments. The resub suggest that differential oviposition may have resulted from reduced rates of egg maturation as a consequence of accumulation of unlaid eggs. Host specialization is probably due to ecological factors as well as an ovipositional preference for onion. Whistlecraft, J. W. & I. J. M. Lepard. 1989. Effect of floodlng on survival of the onion fly Della antlqua (Dlptera: Anthomylldae) md two Parasttolds, Aphaereta pa///pes (Hymnopten: Braconldae) and AIeochara bilineata (Coleoptera: Staphyllnldae). Proceedings of the Entomological Soclety of Ontarlo 120: 45-47. Winter survival of diapause puparia of Delia antiqua at various soil depths, and in various habitats in onion fields, was investigated in the field and in the laboratory in Michigan in 1978-80. pupal survival averaged 89% at all depths examined (3-36cm), with no significant difference between depths. Survival of puparia overwintering in different soil types averaged 78%, with no significant difference between them. Abiotic factors appeared to have little effect on the survival of overwintering puparia in the field. Wh#fleld, G. H., R. I. Carruthem, & D. L. Haynes. 1985. Phenology and control of the onion maggot (Dlptera: Anthomylldae) In Michigan onion production. Agricutture Ecosystems & Environment 12: 189-200. The spatial and temporal distribution of onion damage induced by larval Delia antiqua were studied both within and among onion fields in Michigan. The negative binomial distribution was successfully fined to 68 fields tested. Distribution of damage to onion fields was random in untreated plots and aggregated in insecticide- (fonofos) treated plots early in the season when damage was low. The distribution of plant damage departed significantly from random in all plots later in the season as damage increased. Aggregation Was found to predominate in the region4 an*& of plant damage among fields. Larval-induced plant damage occurred at two distinct periods over the growing Season (mid-June and midJuly), with the 1st generation of larvae contributing to 65% of total damage. kindom or Pseudo-random distribution of plant d-ge earty in the season may be a result of inital mmkJmoviposition during the spring. ~twas suggested that the distribution of damage developed into an aggregated pattern with time due to a number of factors including: Strong preference to ovi~ositon previously damaged onions, larval migration, environmental heterogeneity, densrty-dependent survivorship of larvae, and variability in insecticide efficacy Wlens, M. N., J. E. Rahe, R. S. Vernon & J. A. McLean. 1978. Ovlposltlonal deterrents for HMmya antlqua In hydrated seeds of phaseolus vulgaris. Environmental Entomology 7: 165-167. Extracts from hydrated bean seeds of Phaselous vulgaris L. were evaluated for their abilrty to deter the oviposlional activity of female Delia antiqua in the laboratory. Experiments using choice bioassays with gravid females indicated that extracts deterred the ovipositional response to volatile attractants released by cut pieces of mature onion bulbs. The active component(s) wsa non-volatile, non-polar constituent of hydrated seeds that apparently functioned via a contact stimulus. A computer model for simulating the effects of various control methods on field populations of Delia antiqua on onion in The Netherlands is presented. Simulated releases of sterilized insects, aduhs with genetic translocations or otherwise incompatible strains had different effects on the density-related growth rate used in computer simulations. Translocations may be useful for preventing recovery of a population at the end of a sterile-male release control program, but suppression of a population by release of adults with a single translocation seems impossible, Statistical fluctuations of the growth rate simulated environmental influences, such as weather conditions. The effect of such flu~tuationson the rebase of Sterile flies is discussed. Data is also provided from a sterile-male release experiment against D. antiqua in the field in 1971, with a comparison of the effects of computer simulation. Yarnada, Y., Y. lshlkawa, T. Ikeshojl, & y. Matsurnoto. 1981. Cephallc sensory organs of the onion fly larva, Hylemya antlqua MekW (Dlptera: Anthomylldae) responslble for host- plant finding. Applled Entomology & Zoology 16: 121-128. through irrigation systems, is reviewed. Examples are given of numerous pests controlled in developing countries without machinery, including application in the irrigation water of omethoate (Fohmat) against Delia antiqua on leeks in Egypt. Zotova, Z. Ya & V. V. Inozemtsev. 1986. [Breeding vegetable crops tor resistance to mites and Insect phytophages (survey).]. Sel'skokhozyalstvennaya Blologlya 7: 115-120. he use of selection, hybridization, and heterosis in breeding for resistance in various countries was surveyed. Among several plants investigated, reference to breeding onion for resistance to Delia antiqua was included. Zurllnl, G. & A. S. Roblnson. 1978. Genetic control of Hylemya antlqua Ill. Differences in pupation ablllty between two strains. Researches on Populatlon Ecology 20: 1-14. Zurllnl, G. & A. S. Roblnson. 1979. Larval dispersal as related to denslty In wild and laboratory strains of Della ( = Hylemya) antlqua Melgen. Netherlands Journal ot zoology 29: 402-417. Zurlinl G. & A. S. Robinson. 1980. The effect of crowding on adult populations of Della ( = Hflemya) antlqua (Melgen). Researches on Population Ecology 22: 228-241. In connection with mass-rearing of Delia antiqua for studies on gmetic control, the effect of using 5 levels of density on several population statistics of adutts was studied in the laboratory in he Netherlands. Among the statistics studied were adult life-span, female mating frequency, fecundity and egg hatchability. Females lived significantly longer than males and increasing densrty significantly reduced life-span. Density had no effect on mating frequency. Although total fecundity per female was significantb reduced with increasing density, rate of oviposition was densw-independent. Mean generation time, net reproduction rate (Ro), and capacity for increase (rc) were calculated at different density levels. Values of Ro indicated a one-tailed response, but there was no clear effect of density on rC. Multiple comparisons between variables revealed that the number of mated females Was more imp~rtantthan adult density in affecting total fecundity per cage, and adult lifespan Was the most important factor affecting egg produuctjon. It was calculated that to produce the effect of a single mated female on total fecundity per cage, the overall density would have to be reduced by 0.0023 individuals per cm3. 10.2 Subject Index Subject Page Numbers Attractants Biology and ecdogy Chemical control Chemical residues Subject Page Numbers Chemical resistance Collection records Cultural contrd Damage reports Deterrents Host-finding behaviour Monitoring Subject Page Numbers Natural enemies Ovipositional behaviour Plant disease/resistance Rearing methods Reproductive behaviour Sterile releaseJgenetic control Subject Page Numbers Taxonomylmorph~lo~ 21 3,214,249,253,268