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Xerox University Microfiims 300 North Zeeb Road Ann Arbor, Michigan 48106 76-17,987 HELLER, Paul Robert, 1948- FACTORS INFLUENCING OVIPOSITION OF ALEOCHARA TRISTIS GRAVENHORST (COLEOPTERA; STAPHVLINIDAE), AND ITS PARASITIZATION OF FACE FLY PUPAE. The Ohio State University, Ph.D., 1976 Entomology
Xerox University Microfiims, Ann Arbor, Michigan 4sio6
© Copyright by
Paul Robert Heller
1976 FACTORS INFLUENCING OVIPOSITION OF ALEOCHARA TRISTIS
GRAVENHORST (COLEOPTERA: STAPHYLINIDAE), AND ITS
PARASITIZATION OF FACE FLY PUPAE
DISSERTATION
Presented in Partial Fulfillment of the Requirements for
the Degree Doctor of Philosophy in the Graduate
School of The Ohio State University
By
Paul Robert Heller, B.A., M.S
The Ohio State University
1976
Reading Committee : Approved By
Robert E. Treece David G. Nielsen \K C . \ David J. Horn Adviser Department of Entomology ACKNOWLEDGEMENTS
The author wishes to acknowledge the following for their contributions to the successful completion of this dissertation and the work associated therein.
Appreciation is expressed to the author’s graduate committee which consisted of Dr. Robert E. Treece, Dr. David
G. Nielsen, and Dr. David J. Horn for their professional guidance and assistance in preparing the manuscript.
Appreciation is also extended to Dr. C. R. Weaver for analyzing my experimental data, to Mr. Glenn Berkey and
Mr. Clark Robey for their help in photographic matters.
Thanks are also extended to the Ohio Agricultural
Research and Development Center in providing a Graduate
Research Assistantship during these investigations.
A special note of thanks goes to my mother, father and brother for their continued patience, understanding, and frequent encouragement during the pursuit of this study.
ii VITA
May 11, 1948...... Born - Wooster, Ohio.
1970...... B.A., Malone College, Canton, Ohio
1970-1972 ...... Graduate Research Assistant, Ohio Agricultural Research and Develop ment Center, Wooster, Ohio.
1972...... M.S., The Ohio State University, Columbus, Ohio.
1972-1976 ...... Graduate Research Associate, Ohio Agricultural Research and Develop ment Center, Wooster, Ohio.
1976...... Ph.D., The Ohio State University, Columbus, Ohio.
PUBLICATION
Treece, R. E ., and Paul R. Heller. 197 5. Chemical Fly Control in Ohio Dairy Barns. Ohio Report. 60(6); 99.
FIELDS OF STUDY
Major Field: Entomology
111 TABLE OF CONTENTS
Page
ACKNOWLEDGEMENTS...... ii
VITA...... iii
LIST OF TABLES...... vi
LIST OF FIGURES ...... xviii
INTRODUCTION...... 1
LITERATURE REVIEW ...... 3
GENERAL METHODS AND MATERIALS ...... 11
OVIPOSITION STUDIES ...... 13
General Oviposition Study...... 13
Oviposition Preference Studies with Aleochara tristis ...... 26
Effect of Continuous Male Presence on Egg Production and Viability ...... 33
Effect of Temperature on Egg Production and Viability...... *+l
Effect of Corn in the Diet of A. tristis on Oviposition ...... 52
Discussion of Oviposition Studies...... 61
MORTALITY STUDIES ...... 72
Effect of Temperature on Survival of Unfed Adult A. tristis ...... 72
Effect of Temperature on Survival of Unfed 1st Instar A. tristis Larvae ...... 75
IV Page
Discussion of the Effect of Temperature on the Longevity of Unfed Adult and 1st Instar A . tristis Larvae...... 7 8
ADULT A. TRISTIS SIZE EFFECT STUDIES...... 80
Relationship Between the Weight and Sex of Adult A, tristis ...... 80
Correlation Between Host Pupal Size and Adult Parasite Weight and Sex Ratio...... 80
Discussion of Adult Size Effect Studies. . . . 81
PARASITIZATION STUDIES...... 83
Effect of Temperature and Host Condition on Parasitization of Face Fly Pupae by A. tristis L a r v a e ...... 83
Effect of Soil Moisture and Host Condition on Parasitization of Face Fly Pupae by Aleochara tristis Larvae ...... 8 8
Effect of Host Pupal Size on the Rate of Parasitization of Face Fly Pupae by A. tristis L a r v a e ...... 94
Effect of Host Density and Parasite Density on Rates of Parasitization of Face Fly Pupae by A. tristis...... 97
Effect of Host Pupal Location on Rate of Parasitization by ^ tristis Larvae...... 102
Discussion of Parasitization Studies ...... 105
SUMMARY AND CONCLUSIONS ...... 114
APPENDICES
A. Oviposition Studies...... 119 B. Longevity...... 145 C. Correlation Studies Between Host Pupae Size and Adult Parasitoid Weight and Sex Ratio. 151 D. Parasitism Studies ...... 16 0
BIBLIOGRAPHY...... 17 8
V LIST OF TABLES
Table Page
1. Oviposition of A. tristis held 84 days at 25,6°C.-14 h r s . photophase and 18.3 C 10 hr. scotophase, 30-50% R.H...... 14
2. Frequency summation of eggs produced over 24 hr. intervals by A. tristis at 25.6°C.- 14 hr. photophase and 18.3"C.-10 hr. scotophase, 30-50% R.H...... 17
3. Weekly egg production and percent hatch of eggs produced by surviving female A. tristis at 25.6°C.-14 hr. photophase and 18.3^0.-10 hr. scotophase, 30-50% R.H. . , 18
4. Weekly egg production and percent hatch of eggs produced by surviving paired A. tristis at 25.6^0.-14 hr. photophase and 18.3^C.-10 hr. scotophase, 30-50% R.H. . . 19
5. Average egg production by 22 females with male present and male absent, at 25.6°C.- 14 hr. photophase and 18.3 C.-IO hr. scotophase, 30-50% R.H...... 20
6. Weekly egg production by 22 female A. tristis isolated from male counterparts for one week, at 2 5.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H. 22
7. Weekly egg production by 16 pairs of A. tristis held 84 days at 2 5.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H...... 23
8. Diet composition of each animal...... 26
9. Total number of parasite eggs recovered from feces of four animals maintained on different diets...... 2 8
vx Page Table
10. Average number of eggs per treatment Cpat-type) produced by 50 female A. tristis held 72 hrs. at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr, scotophase, 30-50% R , H ...... 30
11. The distribution of parasite eggs associated with four types of feces . . . 31
12. Number of eggs concealed in four different types of bovine feces ...... 32
13. Oviposition by paired and isolated females held 28 days at 2 5.6°C,-1U hr. photophase and 18.3°C,-10 hr. scotophase, 30-50% R.H...... 34
14. Frequency summary of eggs produced over 24 hr. intervals by paired and isolated female A. tristis held at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R . H ...... 35
15. Number of days paired and isolated female A. tristis oviposited from their initial oviposition ...... 36
16. Weekly egg production and hatch of eggs produced by paired and isolated female A. tristis held 4 weeks at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R . H ...... 37
17. Oviposition by isolated and experimental females held 14 days at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H...... 38
18. Egg production from day 1 through 14 by 10 isolated and 10 experimental female A. tristis...... 39
19. Weekly oviposition by 10 isolated and 10 experimental female A. tristis .... 40
20. Preoviposition period of A. tristis maintained at 5 temperatures...... 43
vii Table Page
21. Oviposition by A. tristis held at five treatment temperatures...... 44
22. The frequency of eggs produced over a 24 hr, interval by A. tristis held at 5 treatment temperatures ...... , . 45
23. Number of days female A. tristis ovi posited from their initial oviposition at five treatment temperatures . , 46
24. Oviposition by 2 0 pairs of A. tristis held 4 weeks at five treatment temperatures ...... 47
25. Egg production by 6 control and 6 transfer pairs of A. tristis held at each of four treatment temperatures. , , 50
26. The frequency of eggs produced over 24 hr. intervals by control and transfer female A. tristis held at 4 treatment temperatures ...... 51
27. Experimental diets on which A. tristis were held at 25.6°C.-14 hr. photophase and 18,3°C.-10 hr. scotophase, 30-50% R.H...... 53
28. The effect of diet-combination on A. tristis oviposition at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H...... 55
29. The effect of diet-combination on length of adult A. tristis preoviposition p e r i o d ...... 56
30. Effect of experimental diets on sus pension of oviposition of A. tristis maintained at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H...... 57
31. Oviposition by 6 pairs of A. tristis maintained on each experimental and control diet at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H...... 58 viii Table Page
32. Weekly oviposition by combined experimental females and control females held at 25,6°C.-14 hr. photo phase and 18,3°C.-10 hr. scotophase, 30-50% R.H...... 60
33. The effect of temperature on the longevity of unfed adult A. tristis . . . 73
34. The effect of temperature on the longevity of 1st instar A. tristis larvae...... 76
35. Effect of host condition (parasitized versus non-parasitized host) and tempera ture on the rate of parasitization of face fly pupae by A. tristis larvae . . . 85
36. Effect of host condition (parasitized versus non-parasitized host) and tempera ture on the rate of superparasitization of face fly pupae by A. tristis larvae. . 87
37. Five soil moisture treatments used in this experiment ...... 89
38. Influence of soil moisture and host condition on rate of parasitization of face fly pupae by 1st instar A. tristis larvae...... 92
39. Influence of soil moisture and host condition on rate of superparasitization of face fly pupae by 1st instar A. tristis larvae...... 9 3
40. Size of host pupae in group one and group t w o ...... 95
41. Effect of host size on rates of parasitization and superparasitization of face fly pupae by A. tristis larvae . . . 96
42. The effect of host density on parasiti zation and superparasitization of face fly pupae by A. tristis larvae...... 98
IX T = , Page
43. The effect of parasite density on parasitization and superparasitization of face fly pupae by A. tristis larvae. . 100
44. The effect of host density on larval efficiency in parasitizing face fly p u p a e ...... 101
45. The effect of parasite density on larval efficiency in parasitizing face fly p u p a e ...... 101
46. The. effect of host pupal location on rate of parasitization and superparasiti zation of face fly pupae by A. tristis larvae...... 104
47. Analysis of variance of the effect of parental age, parental weight and male isolation on preoviposition ...... 120
48. Analysis of variance of the effect of female isolation on egg production. . . . 120
49. Analysis of variance of factors effecting the number of eggs recovered. . 121
50. Analysis of variance of factors effecting the number of eggs concealed. . 121
51. Analysis of variance of the effect of female isolation on percent hatch during week o n e ...... 122
52. Analysis of variance of the effect of female isolation on percent of eggs hatching during week two...... 122
53. Analysis of variance of the effect of female isolation on percent of eggs hatching during week three...... 123
54. Analysis of variance of the effect of female isolation on percent of eggs hatching during week f o u r ...... 12 3
X Table Page
55. Analysis of variance of the effect of female isolation on total number of eggs produced over a 28 day oviposition period...... 124
56. Analysis of variance of the effect of female isolation on the average number of eggs produced per day per female . . . 124
57. Analysis of variance of the effect of female isolation on the percent of days utilized for oviposition...... 125
58. Analysis of variance of the effect of female isolation on the number of days utilized for oviposition...... 125
59. Analysis of variance of the effect of female isolation on the first week of oviposition ...... 126
60. Analysis of variance of the effect of female isolation on the second week of oviposition...... 126
61. Analysis of variance of the effect of female isolation on the third week of oviposition ...... 127
62. Analysis of variance of the effect of female isolation on the fourth week of oviposition ...... 127
63. Analysis of variance of the effect of 14 day male réintroduction on total egg production...... 12 8
64. Analysis of variance of the effect of 14 day male réintroduction on daily egg production per female ...... 128
65. Analysis of variance of the effect of male réintroduction on each successive day of oviposition over a 14 day ovi position period...... 12 9
XI Table Page
66. Analysis of variance of the effect of male réintroduction on the first week of oviposition...... 129
67. Analysis of variance of the effect of male réintroduction on the second week of oviposition...... 130
68. Analysis of variance of the effect of male réintroduction on percent of eggs hatching during the first week of oviposition ...... 130
69. Analysis of variance of the effect of male réintroduction on the percent of eggs hatching during the second week of oviposition...... 131
70. Analysis of variance of the effect of temperature on preoviposition ...... 131
71. Analysis of variance of the effect of temperature on oviposition over a 28 day oviposition period...... 132
72. Analysis of variance of the effect of temperature on the number of days utilized for oviposition...... 132
73. Analysis of variance of the effect of temperature on the percent of days used for oviposition...... 133
74. Analysis of variance of the effect of temperature during the first week of oviposition...... 133
75. Analysis of variance of the effect of temperature during the second week of oviposition ...... 134
76. Analysis of variance of the effect of temperature during the third week of oviposition...... 134
77. Analysis of variance of the effect of temperature during the fourth week of oviposition...... 135
xii Table Page
78, Analysis of variance of the effect of temperature on percent of eggs hatching during week one...... 135
79, Analysis of variance of the effect of temperature on the percent of eggs ha •’hi n g during week tw o ...... 136
80, Analysis of variance of the effect of temperature on percent of eggs hatching during week three...... 136
81, Analysis of variance of the effect of temperature on percent of eggs hatching during week f o u r ...... 137
82, Analysis of variance of the effect of temperature and transfer on the first week of oviposition...... 137
83, Analysis of variance of the effect of temperature and transfer on the second week of oviposition...... 137
84, Analysis of variance of the effect of temperature and transfer on egg viability during the first week of oviposition . . . 138
85. Analysis of variance of the effect of temperature and transfer on egg viability during the second week of oviposition. . 138
86. Analysis of variance of the effect of diet on oviposition during week three. . 139
87. Analysis of variance of the effect of diet on oviposition during week four . . 139
88. Analysis of variance of the effect of diet on egg viability during week three. 140
89. Analysis of variance of the effect of diet on egg viability during week four . 140
90. Analysis of variance of the effect of diet-combination on length of pre oviposition...... 141
X l l l Table Page
91. Analysis of variance of the effect of diet on the suspension of oviposition. , . 141
92. Analysis of variance of the effect of diet and transfer on egg production during week one...... 142
93. Analysis of variance of the effect of diet and transfer on egg production during week two...... 142
94. Analysis of variance of the effect of diet and transfer on egg viability during week one...... 143
95. Analysis of variance of the effect of diet and transfer on egg viability during week two...... 143
96. Analysis of variance of the effect of diet on the first week of egg p r o d u c t i o n ...... 144
97. Analysis of variance of the effect of diet on the second week of egg p r o d u c t i o n ...... 144
98. Cumulative percent mortality of 50 pairs of adult A. tristis held at 5 treatment temperatures ...... 146
99. Analysis of variance of the effect of temperature on male longevity...... 148
100. Analysis of variance of the effect of temperature on female longevity...... 148
101. Cumulative percent mortality of 10 replicates (10 larvae/rep) of 1st instar A. tristis larvae held at 5 treatment temperatures ...... 149
102. Analysis of variance of the effect of temperature on first instar larval s u r v i v a l ...... 150
103. Individual weight and sex of adult A. tristis...... 152
xiv Table Page
104. Analysis of variance of the effect of adult A. tristis weight on sex ratio. . . . 156
105. Effect of increasing host pupal size on adult A. tristis size and sex r a t i o ...... 157
106. Correlation coefficients of the effect of pupal weight on adult weight and adult sex, and adult weight on adult s e x ...... 159
107. Larval survival after 6 0 hrs. exposure,9 summarized from each of the 3 trials held at 3 treatment temperatures...... 161
108. Analysis of variance of the effect of temperature and host condition on parasitization of face fly pupae by first instar A. tristis larvae...... 162
109. Analysis of variance of the effect of temperature on rate of parasitization within treatment one ...... 162
110. Analysis of variance of the effect of temperature on rate of parasitization within treatment two ...... 163
111. Analysis of variance of the effect of temperature and host condition on super parasitization of face fly pupae by first instar A. tristis larvae...... 163
112. Corrected soil moisture weighing based on four-one hundred gram replicates from each of five soil moistures...... 164
113. Larval survival after 6 0 hrs. exposure, summarized from each of the 3 treatment trials held at 5 soil moisture levels . . . 165
114. Analysis of variance of the effect of soil moisture and host condition on parasitization of face fly pupae by first instar A. tristis larvae...... 166
XV Table Page
115. Analysis of variance of the effect of soil moisture and host condition on superparasitization of face fly pupae by first instar A. tristis larvae..... 166
116. Weight, length and width of 2 5 face fly pupae selected for group o n e ..... 167
117. Weight, length and width of 25 face fly pupae selected for group t w o ..... 168
118. Analysis of variance of the pupal weight between group one and group two . . 169
119. Analysis of variance of the pupal length between group one and group two . . 169
120. Analysis of variance of the pupal width between group one and group two...... 170
121. Analysis of variance of the effect of host size on parasitization of face fly pupae by first instar A. tristis larvae. . 17 0
122. Analysis of variance of the effect of host size on superparasitization of face fly pupae by first instar A. tristis l a r v a e ...... 171
123. Analysis of variance of the effect of increasing host density on parasitization of face fly pupae by A. tristis larvae . . 171
124. Analysis of variance of the effect of increasing host density on superparasiti zation of face fly pupae by A. tristis l a r v a e ...... 172
125. Analysis of variance of the effect of increasing parasite density on parasiti zation of face fly pupae by A. tristis l a r v a e ...... 172
126. Analysis of variance of the effect of increasing parasite density on super parasitization of face fly pupae by A. tristis larvae ...... 17 3
XVI Table Page
127. Analysis of variance of the effect of increasing host density on efficiency of first instar A. tristis larvae. . . . 173
128. Analysis of variance of the effect of increasing parasite density on efficiency of first instar A. tristis l a r v a e ...... 174
129. Analysis of variance of the effect of pupal location on parasitization of face fly pupae by A. tristis l a r v a e ...... 174
130. Analysis of variance of the effect of pupal location on superparasitization of face fly pupae by A. tristis larvae. . . 175
131. Analysis of variance of the effect of pupal location on rate of parasitization between treatments one, two and three. . 175
132. Analysis of variance of the effect of pupal location on rate of superparasiti zation between treatments one, two and three. « ...... 176
133. Analysis of variance of the effect of pupal location on rate of parasitization within treatment four...... 176
134. Analysis of variance of the effect of pupal location on rate of superparasiti zation within treatment f o u r ...... 177
xvii LIST OF FIGURES
Figure Page
1. Oviposition by Combined and Paired 16 Females......
2. Regression of Female Weight on Egg P r o d u c t i o n ...... 24
3. Regression of Female Age on Egg P r o d u c t i o n ...... 25
4. Effect of Temperature on Survival of Unfed Adult A. tristis ...... 74
5. Effect of Temperature on Unfed First Instar Larvae...... 77
XVlll INTRODUCTION
In 1965, McGuire in cooperation with the United States
Department of Agriculture, introduced into the United
States from France Aleochara tristis Gravenhorst, a staphylinid predator of the face fly (Drea 1966). Drea
(1966) described the life history of A. tristis including host-range studies with 5 species of Muscidae and 1 species of Anthomyiidae. Allee (1968), Kessler (1971) and Heller
(1972) examined the potential of A. tristis as a natural control agent of the face fly. Jones (1967), Scharff
(Montana State University 1974, unpublished) and Heller
(The Ohio State University 1974, unpublished) completed studies on the release and establishment of this parasite.
Jones (1971) released A. tristis in 21 counties in 9 states. He showed that populations of A. tristis are established in 4 locations, 2 in Nebraska and 2 in Montana.
Scharff (1974) released beetles in the Bitter Root Valley,
Montana in 1968 and 1969. A survey in 1973 indicated that the beetles were established in low numbers west of the
Continental Divide. However, no impact on face fly popu lations was demonstrated. Heller (19 74) released A. tristis in Wayne County, Wooster, Ohio in 1971. Subsequent adult surveys during 1972 and 1973 for parasitoid establish ment were not successful.
This study was initiated to determine factors affecting oviposition by A. tristis and subsequent parasitization of host face fly pupae by first instar parasitoid larvae.
Thus, the following series of investigations were under taken:
1. Oviposition studies: emphasizing general ovi
position behavior, the effect of bovine fecal
dropping on egg recovery and concealment, the
effect of female isolation from males on egg
production and hatch, influence of temperature
on oviposition behavior, and the effect of adult
diet on egg production and viability.
2. Longevity studies: effect of temperature on the
longevity of unfed adult parasites and 1st instar
larvae.
3. General biology studies: effect of host size on
adult sex ratio, and the correlation between host
size and adult parasite size.
4. Parasitism-superparasitism studies: emphasizing
the effect of temperature, soil moisture, host
condition, host size, host parasite ratios and
soil depth on rates of parasitism and super
parasitism. LITERATURE REVIEW
Face Fly History and Distribution
The face fly, Musca autumnalis DeGeer, recognized as a pest of European and Asian cattle, was first discovered
in North America at Middleton, Nova Scotia in 19 52 (MacNay
1952, Voceroth 1953). The geographical distribution of this pest in North America is reported to include all of the provinces of Canada and 40 of the contiguous United
States (Depner 1969, Anonymous 1971). The face fly is primarily considered a pest of horses and cattle, although in some areas it has expanded its host range to include yak, bison, sheep and deer (Anderson and Burger 19 70).
Biology and Life History
Adult face flies normally occupy animal pastures from early April through early November. They are generally active throughout the daylight hours ; fly activity is influenced by temperature, rain, light and wind speed
(Benson and Wingo 1963, Teskey 1969). Temperature has been reported as the single most important factor controlling face fly activity, although light may control the cessation of activity (Teskey 196 9). Activity was not observed below
12.8° C. According to Teskey (1960) and Matthysse (1962) face flies attain maximum abundance on cattle in late July and
August. In the fall a generation of flies is produced which do not mate, nor do the females develop eggs (Teskey 1969).
These are referred to as the hibernating generation, and
Teskey (1969) considers this change a response to decreas ing temperature and photophase. Hibernating adults find shelter in houses, barns and public buildings (Teskey 1969).
Teskey (1969) and Wang (196%) reported extensively on face fly mating and oviposition behavior.. Most matings occur when flies are 3-7 days old, and oviposition commences
2-5 days after mating. Female face flies normally deposit
3-4 batches of 20 eggs during an average life time of 4-8 weeks, with 2-8 day intervals between laying (Killough and
McClellan 1965). Hammer (1941) found the number of eggs per female to average 24.6 while Teskey (196 0) reported an average of 26. The total number of eggs produced per female ranged from 30-230 (Teskey 1969). However, matura tion, rate of development and number of eggs produced are strongly dependent upon diet and its contents (Wang 1964,
Turner and Hair 1967).
Face flies prefer ovipositing in the open pasture on fresh bovine droppings with a high moisture content (Treece
1956, Bay et al. 196 8), Females continue to deposit eggs up to 3 hrs.after the pat is dropped (Teskey 1969).
Occasionally, unsuccessful attempts are made to oviposit and breed in goat, sheep, horse and human manure (Treece
1966, Bay et al. 1968, Vainshtein and Rodova 1940, and
Kobayashi 1919). However, when these feces are recon stituted to a moisture content equal to that of bovine droppings, they serve equally as well as an oviposition and development site (Bay et al. 1968).
Face fly eggs are 3.0 mm. x 0.5 mm. in size and hatch under laboratory conditions C23°C., 40% R.H.),in 6-18 hrs.
Larvae rapidly pass through the 1st instar with two additional instars completed in 4-5 days (Wang 1964).
Prior to pupation, the 3rd instar larva migrates 0.3 - 6.4 meters from the manure pat and pupates in the surrounding pasture (Jones 1969). Pupation normally is completed in one hour, with adults emerging 5-7 days later (Wang 1964).
Economic Importance
The face fly is considered a serious source of irritation and discomfort to pasturing cattle. Bos typicus
Linnaeus. Feeding behavior by the fly around the eyes, nostrils and muzzle induces nervous tension in the animal
(Teskey 1969). In addition to irritation and discomfort, recent studies indicate that the face fly is a possible vector of infectious keratitis and European eyeworm (Barker
1970, Chitwood and Stoffolano 1971, Cobra 1970, and Steve and Lilly 1965). These organisms are thought to be transferred to the animal during the time the flies feed near the animals eyes.
Chemical Control
Entomologists have tested a wide spectrum of chemicals
and application techniques to control the face fly. These
include the use of direct animal sprays, dust-bags, re-
pellants, feed additives, larvicides and chemosterilants
(Dethier 1955, Pales et al. 1961, Treece 1961, Dorsey et al.
1962, Frishman and Matthysse 1966, Dorsey 1968, Bodenstein
et al. 1970, Anonymous 1971, Treece 1962, Jones and Medley
1963, Treece 1964, Lloyd and Matthysse 1970, Rogoff and
Moron 1952, Seawright and Adkins 1968, Cress and Greathouse
1972, Hair and Turner 1966, Lang and Treece 1971). Results
obtained with these methods were neither effective nor
consistent. Treece (1961) suggested 3 reasons why the face
fly is difficult to control: flies feed around the eyes and muzzle in locations where it is difficult to maintain
effective insecticidal residue; only a small portion of the
flies are on the animals at any time ; and there is con
siderable movement of flies from animal to animal within
and between herds.
Biological Control
Considerable time was invested in studying pathogens,
parasites and predators as natural control agents of the face fly. Bacillus thuringinensis Berliner administered as a feed additive failed to control flies at tolerable dosages (Yendol and Miller 1967, Hower and Cheng 1968).
Results from studies utilizing a parasitic nematode,
(Heterotylenchus autumnalis Nickel) of the face fly were inconsistent (Stoffolano and Nickel 1966, Jones and Perdue
1967, Stoffolano 1968, Treece and Miller 1968, Jones 1969,
Stoffolano 1969, 1970, Thomas and Pulter 1970).
Blickle (1961), the first to record parasitism of the face fly in the United States, examined 2,111 face fly pupae in New Hampshire and recorded the following hymenop- terous parasites and percent parasitism: Aphaereta pallipes
(Say) (Bracondiae), 13%; Xyalophora quinquelineata (Say)
(Figitidae), 1%; and Eucoila spp. (Cynipidae), 2.2%.
Initial studies completed by Blickle encouraged additional investigations utilizing hymenopterous parasites as biological control agents of the face fly (Blickle 1961,
Wingo et al. 1967, Benson and Wingo 196 3, Turner et al.
1968, Garry and Wingo 1971, Kessler and Balsbaugh 1972,
Wylie 1973). The main problem encountered with these larval parasites is their inability to emerge from the calcified puparium of the face fly (Fraenkel and Hsiao
1967, Wylie 1973). Three parasites in particular experi ence this problem: Nasonia vitripennis (Walker) (Hair and
Turner 1965); Aphaereta pallipes (Say) (Houser and Wingo
1967); and Muscidifurax raptor Girault and Sanders (Burton 8 and Turner 1968). Wingo (1970) reported only 2 0% natural emergency by Aphaereta pallipes.
In addition to the latter parasites, Hammer (1941) noted that species in the genera Vespa, Mellinius and the fungus Empusa attack the face fly. Studies completed with
2 staphylinids, Aleochara tristis and Aleochara bimaculata
Gravenhorst, revealed that both insects are predaceous on immature stages of face fly, and A. tristis is parasitic on face fly pupae (Drea 1986, Anonymous 1967, Jones 1967,
Wingo et al. 1967, Allee 1968, Burton and Turner 1968,
Kessler 1971, Heller 1972).
Aleochara Tristis Introduction and Life History
Parasitism by members of the genus Aleochara was first reported by Sprague in 1870. Eighty-seven species of
Aleochara are known, but only 8 hosts are recorded (Moore and Legner 1971). Extreme interest was shown in A. tristis because of its specificity on the face fly.
A. tristis, a native of Central Europe, was first established in culture in the United States by Jones (1967).
The host-parasite relationship between the face fly and A. tristis is of extreme importance (Anonymous 1967). Both insects are among the first visitors to bovine droppings.
Female Aleochara tristis oviposit in fresh dung. The egg is ovoid, 0.5 mm. x 0.3 mm., varying in color from pale- yellow to yellow-brown. Campodeiform larvae hatch in 4-5 days and immediately begin searching for host pupae in and near the dung pat. When contact is established, the parasite larva examines the host and then bores its way into the pupa. The 2nd and 3rd instar scarabeiform parasite larvae complete development in 6-14 days within the host pupa. Pupation normally occurs in the host with the entire life cycle completed in 30-40 days (Drea 1966). Parasitized face fly pupae are distinguished from non-parasitized hosts by their red-pink coloration which appears 10-12 days following parasite entrance (Drea 1966, Heller 1972). Adult beetles are 0.5 cm. long and are entirely black except for a rufous area on the apical portions of each elytron and a slightly reddish tinge on the tibiae and tarsi. The uni form punctation of the pronotal disc readily distinguishes this species from the similar North American species A. bimaculata and A. bipustulata (L.) (Drea 1966).
Adults can be sexed by examining the last abdominal tergite. Anesthetized beetles are placed on a glass slide, and pressure is applied with a second slide causing extension of the last tergite. Females are distinguished from males by a small lobe where the two overlapping parts of the last tergite meet at the ventral midline (Drea 1966).
The corresponding abdominal tergite of the male lacks this lobe. A sex ratio of 1:1 was reported from field collected material (Drea 1966). 10
Host range studies completed with A. tristis revealed two additional species of Muscidae, Orthelia corncina (F.) and Orthelia caesarion Meigen, are attacked by 1st instar
A. tristis larvae (Drea 1966, Jones 1967). House fly
(Musca domestica Linnaeus) and stablefly pupae (Stomoxys calcitrans (L.)) were unacceptable hosts (Jones 1967). GENERAL METHODS AND MATERIALS
Rearing Procedures For The Face Fly and Aleochara tristis
The face flies used in this study were from a stock maintained in culture for 10 years at The Ohio Agricultural
Research and Development Center, Wooster, Ohio 44691. They were reared at approximately 2 3°C-40% R.H. on a daily free-choice diet of sugar, reconstituted non-fat dry skim milk and water.
Face fly oviposition media, consisting of fresh- rectally collected bovine feces, was transferred to 17.5 cm.
X 30.0 cm. X 5.0 cm. plastic trays lined with plastic wrap.
These trays were placed in individual fly cages where face flies were allowed to oviposit for 2 0 minutes. Then the trays were removed and placed in a pupation chamber lined with finely-ground vermiculite. Upon completion of larval development (4-5 days), face fly larvae moved from the trays and pupated in the vermiculite. Pupae then were sifted free from the vermiculite and placed in the fly emergence cages.
The original culture of A. tristis was established from 75 8 parasitized face fly pupae received from Dr. C. M.
Jones, USDA, Lincoln, Nebraska, on March 22, 1971. They were placed on moist sand and later transferred to a
11 12 rearing cage where they were held until emergence. The
techniques used in rearing this parasite followed those of
Drea (1966) and Jones (1967). A 55.0 cm. x 55.0 cm. x 25.0
cm. cage was made of plywood, with a muslin sleeve on one
side and plastic screen both on top and bottom. A very
fine mesh (90.0 x 90.0) was used on the top of the cage to prevent adult parasites and larvae from escaping. The bottom was lined with a screen (45.0 x 45.0 mesh) which
allowed hatching 1st instar larvae, but not adults, to drop through. A funnel constructed of industrial grade plastic,
attached under the cage, led the falling insects to a 1- gallon collecting container. The bottom of this container was lined with a finely ground vermiculite-sand mixture.
This mixture aids the footing of 1st instar larvae as they
bore into the face fly puparium (Jones 1967).
Face fly pupae (48 h r s . old) were replaced in the parasitization chamber at 24 hr. intervals. Parasitized
face fly pupae were then placed in 7 oz. disposable cups, where they were held until emergence.
The beetles were maintained primarily on a diet of
face fly eggs and larvae. Occassionally, the diet was
supplemented with house fly eggs, larvae, and crushed
pupae. OVIPOSITION STUDIES
General Oviposition Study
Methods and Materials
The objective of this study was to determine (1) the fecundity of A. tristis females over a 12 week period and,
C2) the effect of female age and weight and the influence of female isolation on fecundity and fertility.
Two-hundred parasitized face fly pupae were placed in individual shell vials. Upon emergence each beetle was anesthetized with COg, sexed and weighed. Adults were paired (80 males and 80 females) according to weight and each pair was placed in an individual oviposition chamber consisting of a 5 cm. circular petri dish lined with filter paper. These were then placed in a Sherer Model CEL 25 5-6 growth chamber and held 84 days at 14 hrs. photophase at
25.6°C, 30-50% R.H. and 10 hrs. scotophase at 18.3°C., 30-
50% R.H. Their daily diet consisted of water and two crushed face fly pupae.
Oviposition was recorded daily for 12 weeks. Eggs were collected and held for 7 days within the Sherer Chamber
Sherer Chamber (Scherer-Gillett Co.), Marshall, Michigan.
13 14 to record hatch.
Results
Seventy out of 80 pairs of A. tristis successfully produced fertile eggs. Females, with few exceptions, commenced ovipositing 7-8 days after they were paired
(Table 1). The length of preoviposition was neither shortened nordelayed by differences in female weight or age
(Appendix A, Table 47).
Table 1. Oviposition of A. tristis held 84 days at 25.6°C.- 14 hrs. photophase and 18.3 C.-IO hrs. scotophase, 30-50% R.H.
Range Mean - SD
Preoviposition Period 5-17 days 7.5 Î 3.3 days Female Weight 2 .88-6. 88 mg. 4.8 — 0.8 mg. Female Longevity 11-84 days 60.7 - 23.5 days Eggs/Female/Day 0-67 eggs 8.1 - 4.6 eggs Total Eggs/Female 2-1,687 eggs 501.5 -434.5 eggs
A total of 35,106 eggs were produced by 70 females over a 12 week period for an average of 502.0 eggs per female
(Table 1). The maximum number of eggs produced by an individual female was 1,687 (Table 1). Most females were 15
synovigenic, ovipositing eggs on a daily basis. Females
most frequently produced 11-15 eggs over a 24 hr. interval
(Table 2), with a 24 hr. observed maximum of 67.
The oviposition pattern of combined females, those
with males present or absent, consisted of a series of
weekly fluctuations through week 10, with one week intervals
between consecutive production increases and decreases
(Figure 1). Females averaged 50 or more eggs through week
10, followed by 2 successive weeks of decline (Table 3).
Weekly egg production ranged from a low of 4.1 per female
during week 1 to a high of 88.2 eggs per female during week
6 (Table 3).
A comparison of the oviposition patterns of paired
females (male present) and combined females showed that
both followed a comparable series of weekly fluctuations
(Figure 1 and Table 4). However, paired females averaged more eggs per week than combined females and recorded the highest average during week 10 of 117 eggs per female
(Table 4).
Results from this study also showed that individual
egg production, by 22 females isolated from males because
of male death, decreased with an extended length of isola
tion. Prior to male death, the combined pairs averaged 58
eggs per female compared to 36 eggs per female following
periods of isolation (Table 5), 16
110 . /\ /V/ 100 _
90
80 A/ a\ « o8 tu M V p4 60 . m » (p M 50 - O Z 40 J > < 30 . *: Combined Females 20 - •iiiiiiiiiii*: Paired Females
10 .
T T 1 T I i I 2 4 6 7 9 10 11 12 Week
Figure 1 : Oviposition by Combined and Paired Females. 17
Table 2. Frequency summation of eggs produced over 24 hr, intervals by A. tristis at 25.6°C.-14 hr. photo phase and 18.Y°C.-10 hr. scotophase, 30-50% R.H,
Range and Number Frequency of Percent of Total of Eggs Collected Collections Collections
1-5 465 18.5 6-10 493 19.6 11-15 551 21.9 16 20 457 18.2 21-25 304 12.1 26-30 135 5.4 31-35 66 2.6 36-40 26 1.0 41-45 10 0.5 46-50 4 0.2 51-55 1 0.04 56-60 1 0.04 61-65 - - 66-70 1 0.04 Table 3. Weekly egg production and percent hatch of eggs produced by surviving female A. tristis at 25.60C.-1% hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H.
No. Total Average No. Females No. Eggs Eggs Per Female Average Percent Week Alive Produced Per Weeki SD Eggs Hatch
1 70 287 4.1 ± 7.6 93.2 2 70 5113 73.0 - 37.0 87.0 3 66 3907 59.2 - 37.4 82 .4 ' 4 54 4.3 93 81.4 - 47.8 85.0 5 49 3231 65.9 - 42.1 90.1 6 45 3901 88.2 - 51.6 93.5 7 43 2794 65.0 - 44.7 88.9 8 42 3515 83.7 - 62.4 91.8 9 41 2510 61.2 - 62.1 98.0 10 36 2455 68.2 - 72.6 98.2 11 35 1721 49.2 - 56.6 94.5 12 34 1279 38.8 - 51.1 94.8
00 Table 4. Weekly egg production and percent hatch of eggs produced by surviving paired A. tristis at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scoto phase, 30-50% R.H.
No. Total Average No. Eggs Average Pairs No. Eggs Per Female Percent Week Alive Produced Per Week + SD Eggs Hatch
1 70 287 4.1 - 7.6 88.5 2 68 4985 73.3 - 37.2 86.8 3 52 3664 70.5 Î 32.8 84.1 4 37 3432 92.8 i 42.7 86.8 5 29 2281 78.7 i 38.8 89.9 6 27 2661 98.6 ± 49.6 93.4 7 27 2089 77.4 ± 46.2 88.4 8 27 2928 108.4 t 56.7 92.7 9 20 2040 102.6 i 58.4 97.5 10 19 2233 117.5 i 65.5 97.9 11 17 1439 84.6 i 52.0 94.3 12 16 117 69.8 i 54.0 94.7
CO Table 5. Average egg production by 22 females with male present and male absent, at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H.
Egg Production of 22 Females
Pair Male Present—^ MaleAbsent—/ No. No. Weeks No. Eggs Average No. Weeks No • Eggs Average
1 2 92 46.0 10 122 12.2 2 3 160 53.3 9 293 32.6 3 4 150 37 .5 8 196 24.5 4 4 94 23.5 4 242 60.5 5 5 130 26.0 7 133 19.0 6 4 340 85.0 8 514 64.3 7 4 163 40.8 8 278 34.8 8 4 33 8.3 8 11 1.4 9 4 395 98.8 1 59 59.0 10 9 774 86.0 3 86 28.7 11 5 217 43.4 2 191 95.5 12 5 361 72.2 7 405 57.9 13 5 463 92.6 7 436 62.3 14 4 400 100.0 8 314 39.3 15 2 14 7.0 10 212 21.2 16 9 843 93.7 3 69 23.0 17 11 847 77.0 1 94 94.0 18 3 148 49 . 3 3 1 0.3 19 5 366 73.2 7 73 10.4 20 3 132 44.0 9 249 27.7 21 2 97 48.5 1 3 3.0 22 4 287 71.8 8 103 12.9 Total = 8267 4084 Average = 295.7 58.1 185.6 35.7 SD = 249.0 28.6 144.0 27.8 a/ An analysis of variance completed on affect of female isolation on average egg ro production was significant at p = 0.05 (Appendix A, Table 48). o 21
Females isolated during weeks 1-3 usually responded by
producing a few eggs (1-70) per week over an extended period
of 5-6 weeks, while females isolated during weeks k and 5 produced a large complement of eggs (70-16 9) for 2-3 weeks
prior to the suspension of egg production (Table 6).
Isolated females seldom continued producing eggs following
an isolation period of 4-5 weeks.
Analysis of oviposition for 84 days by 16 paired
females showed no linear relationship between egg production
and female age or weight. The sixteen females weighed an
average of 4.6 mg. and averaged 7 8 eggs per week (Table 7).
Variations in weekly egg production showed no linear relationship with female weight (Figure 2). The effect of
female age on egg production from day 14 through day 84
showed no linear relationship (Figure 3).
In conclusion, females produced an average of 502 eggs over an 84 day oviposition period. Egg production was
affected by male removal, but not by female age or weight. Table 6. Weekly egg production by 22 female A. tristis isolated from male^ counterparts for one week, at 25.6*^ü.-lU hr. photophase and 18.3°C.- 10 hr. scotophase, 30-50% R.H.
Pair Total Egg Production/Week/Female No. Wk 2 Wk 3 .Wk 4 Wk 5 Wk 6 Wk 7 Wk 8 Wk 9 Wk 10 Wk 11 Wk 12
1 8 48 20 20 20 6 0 0 0 0 0 2 72 86 58 14 1 1 0 1 3 22 73 44 51 6 0 0 0 4 87 83 45 27 0 0 0 0 5 46 20 41 9 0 0 17 6 97 113 88 124 92 0 0 0 7 55 102 7 25 27 28 35 0 8 0 0 6 5 0 0 0 0 9 59 10 86 0 0 11 105 86 0 0 0 0 0 12 169 106 118 12 0 0 0 13 86 81 125 100 44 0 0 14 149 96 15 3 1 0 2 48 15 34 22 22 66 65 3 0 0 0 0 16 45 22 2 17 94 18 1 0 19 63 10 0 0 0 0 0 20 20 46 86 51 45 0 1 0 0 21 3 22 54 46 3 0 0 0 0 0
fO ND 23
Table 7. Weekly egg production by 16 pairs of A. tristis held 84 days at 25.60C.-1U hr. photo phase and 18.3°C.-10 hr. scotophase and 3 0-50% R.H.
Source Range Average i SD
Female Wt. 2.89-6.88 mg. U.58 ± 1.20 mg.
Egg 12-lUO eggs 78. 93 ± 35.96 eggs Production 24
150 Y= 2= 0.001
130 m E Q) 110 k k V 90 A m O' O' 70 H o z 50
> < 30
10
1 2 3 4 5 6 7
Weight of Female (mg.)
Figure 2; Regression of Female Weight on ” Egg Production. 25
280 Y= 0.68 U1 + 162.23 r2- 0.17
260
•H 240
220 n 200
180
> 160
140
120
2114 28 35 42 49 56 63 70 77 84 Days Figure 3; Regression of Female Age on Egg Production, 26
Oviposition Preference Studies with Aleochara Tristis
Methods and Materials
This study was designed to determine (1) the influence of bovine diet and subsequent fecal material on A. tristis oviposition, and (2) if the presence of face fly eggs enhanced the acceptability of a pat as an oviposition site for A. tristis.
Fifty male and 50 female A. tristis, 12-14 days old, were placed into a 33.3 cm. x 7.7 cm. circular dish lined with sterilized soil, containing four 20.0 cm. diameter pats (one pat made from the individual fecal dropping of a single animal. Table 8). After 72 hrs. of exposure, the adults were removed from the arena and each pat was inspected for eggs.
Table 8. Diet Composition of Each Animal
Animal Diet ^, No. Composition-
1905 Alfalfa hay
2033 Corn silage, alfalfa hay, alfalfa pellets, D 372 grain supplement
1916 Corn silage, alfalfa hay, D 372 grain supple ment
212 0 Short-cut corn and D 3 53 grain supplement
a/ Animals are listed in order of decreasing alfalfa and increasing corn in their diets. 27
A. tristis were exposed to four fecal treatments, as
follows :
Treatment 1. No face fly eggs were present in feces
used.
Treatment 2. Feces used from animals 2120 and 1905
were seeded with face fly eggs, while
feces used from animals 2 033 and 1916
did not contain face fly eggs.
Treatment 3. Feces used from animals 2033 and 1916
were seeded with face fly eggs, while
feces used from animals 212 0 and 1905
did not contain face fly eggs.
Treatment 4. Face fly eggs were present in all feces
used.
Four replicates were completed per treatment and all were held in a Scherer growth chamber maintained at 25.6°C-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H.
Results
Results from this study confirm that A. tristis prefered
ovipositing in feces from animals maintained on a high ration of alfalfa hay (Tables 8 and 9). However, the
absence or presence of face fly eggs within the pat neither enhanced nor hindered its attractiveness as an oviposition
site to A. tristis (Table 10). 28
Table 9. Total number of parasite eggs recovered from feces of four animals maintained on different diets.
Animal—^ Total No.— Average No. Parasite Eggs (Per Replicate) Percent
1905 593 148.2 40.6
2033 391 97.7 26.7
1916 273 68.3 18.7
2120 205 51.3 14.0
a/ Total number of eggs recovered from 16 pats.
b/ Analysis of variance completed on the effect of feces from each animal on egg recovery was significant at p=0.05 (Appendix A, Table 49).
One thousand four hundred sixty two eggs were re covered from all four treatments with A. tristis depositing
40.6% of these eggs on or beneath pats constructed from feces of animal 1905, maintained on a high ration of alfalfa hay (Table 8). The number of eggs recovered from pats constructed from feces of animals on reduced rations of alfalfa hay successively decreased (Table 9).
An average of 58 eggs were recovered from feces of animal 212 0, with no alfalfa hay present in its diet, compared to 97.7 eggs from pats made from the feces of animal 2 033 which contained alfalfa hay.
Egg placement by A. tristis also was altered by feces 29 composition. Five hundred and ninety three eggs were recovered from pats made from feces of animal 1905, with
90.4% (% top pat + % edge pat) of’them associated with the feces (Table 11). However, few eggs were recovered from the soil beneath these pats. Animals 212 0 and 1916, receiving reduced quantities of alfalfa hay in their diets, seldom had eggs associated with the top or edge of their feces (Table 11). A. tristis usually preferred ovipositing in the soil beneath these feces. Two hundred and five eggs were recovered from droppings of animal 2120 with 132
(64.4%) distributed in the soil beneath compared to 25 eggs recovered from the feces. Hence, bovine fecal compo sition varies in its acceptability as an oviposition site for A. tristis, and oviposition behavior may be influenced by bovine diet.
The concealment of eggs within feces was affected by fecal composition. Females concealed 90.9% of those eggs associated with pats constructed from feces of animal 1905
(Table 12). Those eggs recovered from the 3 remaining droppings seldom were concealed, with an observed conceal ment range of 3.6-12.3% (Table 12), while the remaining eggs were exposed on the top or edge of the pat. Table 10. Average number of eggs per treatment (pat-type) produced by 50 female A. tristis held 72 hrs. at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H.
■■ ■ ■ ■ ' T Treatments— No. One Two Three Four Average
1905 33.70 46.93^/ 53.44 26.46-^ 40.13
2033 28.45 33.33 21.46-^ 2 8.04-^ 27.82
1916 18.23 10.96^/ 13.77 30.16-'^ 18.28
2120 19.61 8.70 11.34-^ 15.34^/ 13.75
a/ An analysis of variance completed on the effect of the absence or presence of face fly eggs on egg recovery from feces was not significant at p=0.05 (Appendix A, Table 49).
b/ Face fly eggs present in feces.
W o Table 11. The distribution of parasite eggs associated with four types of feces.
Parasite Egg Distribution— Feces of Total No. Top of Pat Edge of Pat Soil Beneath Animal No. Eggs N o . % No. % N o . %
1905 593 263 44 . 35 273 46 . 03 57 9 .61
2033 391 73 18 .67 155 39.64 163 41.68
1916 273 12 4,40 72 26.37 189 69.23
2120 205 25 12.19 48 23.41 132 64.39
a/ An analysis of variance on the effect of feces on egg placement was significant at p=0.05 (Appendix A, Table 49).
CO Table 12. Number of eggs concealed in four different types of bovine feces.
Feces From No. No. Percent Animal Eggs . Eggs b/ Eggs No. Recovered— Concealed— Concealed
1905 536 487 90.86
2033 228 20 8.77
1916 84 3 3.57
2120 73 9 12.33
a/ Number of eggs recovered from only the feces.
b/ An analysis of variance completed on the effect of feces composition on egg concealment was significant at p=0.05 (Appendix A, Table 50).
CO IV> 33
Effect Of Continuous Male Presence On Egg Production And
Viability
Methods and Materials
The purpose of this study was to evaluate the effect
of continuous male presence on egg production and viability.
Two treatment groups of 20 adult pairs, 0-24 hrs. old,
with each pair contained in a 5 cm. petri dish lined with
filter paper, were selected and held 4 weeks in a tempera
ture chamber at 25.6°C-14 hr. photophase and 18.3°C.-10 hr.
scotophase, 30-50% R.H. Daily, they were provided a diet
of water and 2 crushed face fly pupae.
Control females remained with males throughout the
study, while experimental females were isolated from their male counterparts following their initial oviposition. Egg
production per female was monitored at 24 hr. intervals.
All eggs collected were held with treatment pairs for 7
days to determine viability.
At the conclusion of 4 weeks, the experimental females
were randomly divided into two groups of 10. Ten females
remained isolated as controls, while 10 additional females
were reintroduced to males of identical age. A 14 day
comparison was completed between the two treatments to
determine the effect of male réintroduction on egg pro
duction and viability. 34
Results
Results from this study confirmed that egg production and frequency of daily oviposition were reduced by females isolated from males. Paired females produced 4,96 3 eggs over 28 days, in comparison to isolated females producing
2,051 eggs (Table 13). Egg viability was not altered by the absence or presence of males (Appendix A, Tables 51-54).
Table 13. Oviposition by paired and isolated females held 28 days at 2 5.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H.
Egg Production Female Treat 2 8 Days/Female—^ Daily/Female—^ ment Total Range Av. t SD Range Av. 1 SD
Paired 4,963 82-394 251.9 - 84.1 0-53 9.0 - 3.0
Isolated 2,051 2-110 102.6 - 58.7 0-27 3.7 t 2.1
a/ An analysis of variance completed on the effect of male presence on egg production was significant at p=0.05 (Appendix A, Tables 55, 56).
Paired females laid an average of 9 eggs per day
(Table 13), with 11-15 eggs deposited most frequently
(Table 14). Isolated females, less persistent in daily oviposition, averaged 3.7 eggs per day and seldom ovi posited more than 1-10 eggs over a 24 hr. interval (Table
14). Table 14. Frequency summary of eggs produced over 24 hr. intervals by paired and isolated female A. tristis held at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H.
Range of Frequency of Collections Percent Total Collection Eggs Treatment (Female Treatment (Female) Collected Paired Isolated Paired Isolated
1-5 66 113 17.6 41.4 6-10 79 90 21.1 33.0 11-15 88 51 23.5 18.7 16-20 68 12 18.1 4.4 21-25 50 5 13.3 1.8 26-30 14 1 3.5 0.4 31-35 8 1 3.1 0.4 36-40 1 - 0.3 -
41-45 - --- 46-50 ---- 51-55 1 0.3
CO cn 36
Daily oviposition patterns, based on the time interval between the initial oviposition and remaining days of the
28 day study, revealed that isolated females were less productive than paired females in producing eggs on a regular, daily basis. Paired females utilized 89% of those days available for oviposition for an average of 18,9 days per female (Table.15) while isolated females utilized only
61% of the days, an average of 13 days per female (Table 15)
Table 15. Number of days paired and isolated female A. tristis oviposited from their initial ovi- position.
Female Oviposition Treat Days ,Available Days Utilized—^ ment Range Av. + SD Range Av. + SD A v . % + SD
Paired 17-24 21.1 - 5.6 13-22 18.9 -2.4 89.0 - 8.0
Isolated 20-25 22.0 - 1.2 2-21 13.7 -5.2 61.0 - 2.3
a/ An analysis of variance completed on the effect of male presence on the days utilized and percent days utilized was significant at p=0.0 5 (Appendix A, Tables 57 and 58).
Weekly egg production comparisons, commencing with week 2, showed that isolated females successively produced fewer eggs than paired females (Table 16). Egg production by isolated females declined from 39.8/female during week 2 to 22.4/female during week 4 (Table 16). Paired females Table 16. Weekly egg production and hatch of eggs produced by paired and isolated female A. tristis held 4 weeks at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H.
a/ Egg Production Treatment Week Total No. % Hatch Eggs/Female/Week i SD
Paired 1 132 93.0 6.6 t 9.7 2 1464 88.4 73.2 ± 2.8 3 1492 83.1 74.6 ± 3.0 4 1950 88.4 97.4 i 4.0
Isolated 1 169 93.9 8.4 + 1.0 2 797 91.5 39.8 + 2.3 3 636 95.5 31.8 i 2.7 4 449 99.0 22.4 i 2.6
a/ An analysis of variance completed on the effect of male presence on weekly egg production was significant at p=0.05 (weeks 2-4), but was not significant for egg hatch (Appendix A, Tables 59-62 and Appendix A, Tables 51-54). 38
continued producing 70-100 eggs per female per week (Table
16).
Results from the 14 day male réintroduction study
showed that experimental females produced (2,191) more
eggs than isolated females (131) over a 14 day oviposition
period (Table 17).
Table 17. Oviposition by isolated and experimental females held 14 days at 2 5.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H.
Egg Production 14 Days/Female^/ Daily/Female^./ Treatment Total Range Av. I SD Range Av. i SD
Experi 2,191 133-276 219.0 ± 45.7 0-57 15.6 ± 8.2 mental
Isolated 133 0-62 13.1 - 22.0 0-18 0.9 + 2.8
a/ An analysis of variance completed on the effect of male presence on 14 day and daily egg production was significant at p=0.05 (Appendix A, Tables 63 and 64).
The experimental females responded to male réintro
duction and increased egg production to 72 eggs (within 24 hrs. ), compared to isolated females producing only 2 2 (Table
18). Experimental females consistently produced eggs
through day 14, while isolated female egg production de
clined to 0 (Table 18). Table 18. Egg production from day 1 through 14 by 10 isolated and 10 experimental female A. tristis.
a/ Egg Production- Experimental Females Isolated Females Day Total No. Average Total No. Average
1 72 7.2 22 2.2 2 166 16.6 19 1.9 3 152 15.2 31 3.1 4 133 13.3 13 1.3 5 215 21.5 23 2.3 6 205 20.5 15 1.5 7 185 18.5 0 - 8 189 18.9 1 0.1 9 155 15.5 0 - 10 138 13.8 5 0.5 11 181 18.1 0 - 12 196 19.6 0 - 13 90 9.0 3 0.3 14 114 11.4 1 0.1
a/ An analysis of variance completed on the effect of male presence on daily egg production was significant at p=0.05 (Appendix A, Table 65).
CO CO 40
Experimental females averaged 112.8 eggs per week following a 1 week exposure period to males (Table 19), while isolated females averaged only 12.3 eggs per week
(Table 19).
At the conclusion of week 2, isolated females produced only 1/10 0 as many eggs as experimental females (Table 19).
Egg viability was not affected by male death until week 2, with only 6 7% of isolated female eggs hatching.
Hence, continuous male contact is necessary for egg pro duction on a daily basis.
Table 19, Weekly oviposition by 10 isolated and 10 experimental female A. tristis
a/ Egg Production Treat Total Av. / Week ment Week No/Week t SD % Hatch
Experi 1 1128 112.8 Î 28.8 95.3 mental 2 1063 106.3 i 23.9 98.6
Isolated 1 123 12.3 i 20.6 99.7 2 10 1.0 i 2.5 66.7
a/ An analysis of variance was completed on the effect of male presence on weekly egg production and % hatch. F values were significant for egg production during weeks 1 and 2. Egg hatch was not significantly affected until week 2 (Appendix A, Tables 66-69). 41
Effect Of Temperature On Egg Production And Viability
Methods and Materials
The purpose of this experiment was to evaluate the effect of temperature on weekly egg production and vi ability.
Twenty pairs of 0-24 hr. old A. tristis were held 4 weeks at each treatment temperature: 32.2°C, , 26.7°C.,
25.6°C.-18.3°C., 21.1°C., and 12.8°C, t 0.7°C. 14 hr. photophase, 30-5 0% R.H. Each pair was placed in an individual 5 cm. plastic petri dish lined with filter paper and maintained on a daily diet of water and 2 crushed face fly pupae. Egg production per female was monitored at 24 hr. intervals. Eggs collected from each temperature were held at that temperature for 7 days to determine egg viability.
At the conclusion of the 4 week study, a temperature transfer study was initiated. The purpose of this experi ment was to evaluate the effect of two 7 day temperature transfers on female productivity and egg viability.
Twelve pairs of adults were randomly selected from each constant temperature: 32.2°C., 26.7°C., 21.1°C. and
12.8°C. Six pairs were held 14 days at each constant temperature, acting as controls. The six remaining pairs were transferred as follows: 42
Initial Temperature 1-7 Day Transfer 8-14 Day Transfer
32,2°C. 12.8°C. 32.2°C.
26.7°C. 12.8°C. 26.7°C.
21.1°C. 12.8°C. 21.1°C.
12.8°C. 25.6-18.3°C. 12.8°C.
The effect of temperature and transfer was measured by comparing egg productivity and viability between control females and transferred females at the end of each 7 day transfer.
Adults were maintained on a diet of crushed face fly pupae and water during the transfer study. Eggs were collected and held for 7 days to record viability.
Results
The duration of preoviposition and female productivity were directly dependent on temperature. Females main tained at 32.2°C. produced fertile eggs within 2-3 days, while those held at 4-successive, lower temperatures did not respond as rapidly (Table 20).
Daily egg production was also altered by increasing temperature. Females held at 32.2°C. averaged 10.7 eggs per day over the 2 8 day oviposition period, while females held at four successive, lower temperatures were not as productive (Table 21). Females held at temperatures above
21.1°C. usually deposited 11-15 eggs most frequently while 43
Table 20. Preoviposition period of A. tristis maintained at 5 temperatures.
Temperature Length of Preoviposition (Days)— (°C.) Range Average ± SD
3 2 . 2 ° 2-6 2.7 + 1.3
2 6 . 7 ° 2-28 6.7 + 7.5
25,6-18.3° 6-13 7.6 + 1.8
21.1° 6-28 11,0 + 5.9
12.8° 9-28 25.5 + 6.2
a/ An analysis of variance completed on the effect of temperature on length of preoviposition was significant at p=0.05 (Appendix A, Table 70).
those held at 21.1°C. or lower seldom produced as many as
10 eggs during a 24 hr. interval (Table 22). Also, only 3 females held at 12.8°C. successfully produced eggs, with an average of 0.05 eggs per female (Table 21). Daily ovi position patterns, based on the time interval between the initial oviposition through day 28, showed that decreasing temperatures reduced the number of days that a female ovi posited (Table 23).
The combined females produced 1,5 53 eggs during week 1 with females held at 32.2°C. producing 6 5.2% of the eggs
(Table 24). Egg production over the three remaining weeks Table 21. Oviposition by A. tristis held at five treatment temperatures
a/ Egg Production/28 Day Total—' Temperature OC. Total Egg Range Average t SD Percent Total
32.2° 5719 1-585 10.7 + 5.8 34.1
26.7° 4373 0-371 7.9 1 4.0 26.1
25.6-18.3° 4718 82-400 8.4 Î 3.1 28.1
21.1° 1948 0-230 3.5 t 2.4 11.6
12.8° 8 0 — 5 0.01+ 0.04 0.05
a/ An analysis of variance completed on the effect of temperature on egg production was significant at p=0.05 (Appendix A, Table 71).
-p -p 45
Table 22. The frequency of eggs produced over a 24 hr. interval by A. tristis held at 5 treatment temperatures.
Range of No. Frequency Percent Temperature Eggs of of Total °C. Collected Collections Collections
32.2 1-5 55 13.9 6-10 86 21.8 11-15 90 22.8 16-20 61 15.5 21-25 61 15.5 26-30 25 6.3 31-35 10 2.5 36-40 3 0.8 41-45 2 0.5 46-50 1 0.2
26.7 1-5 74 19.5 6-10 106 28.0 11-15 99 26.2 16-20 58 15.3 21-25 29 7.7 26-30 10 2.6 31 = 35 2 0.5
25.6-18.3 1-5 6 6 18.7 6-10 73 20.7 11-15 89 25.2 16-20 58 16.4 21-25 48 13.6 26-30 11 3.1 31-35 4 1.1 36-40 2 0.8 41-45 1 0.3 46-50 0 - 51-55 1 0.4 21.1 1-5 108 43.2 6-10 75 30.0 11-15 44 17.6 16-20 16 6.4 21-25 7 2.8 12.8 1-5 4 80.0 6-10 1 20.0 Table 23. Number of days female A. tristis oviposited from their initial oviposition at five treatment temperatures.
Female Oviposition Temp. No. , Days Available Days Utilized— (°C. ) Pairs-' Range Av. ± SD Range Av 3 SD Av. % + SD
32 .2 15 23-26 25.5 - 1.1 21-26 24.5 - 1.6 95.0 ! 0.0
26.7 17 17-25 23.6 i 2.0 15-25 21.8 - 3.1 91.0 - 1.0
25.6- 15 15-22 20.4 - 2.0 13t 21 18.3 - 2.6 90.0 - 8.0 18. 3
21.1 19 8-23 17.9 - 4.4 1-21 13.2 - 5.9 67.0 Î28.0
12.8 3 14-19 17.0 - 2.6 1-2 1.7 - 0.6 9.0 - 2.0
a/ Analyzed only pairs with male present throughout the 2 8 day oviposition period.
b/ An analysis of variance completed on the effect of temperature on the number of days utilized and percent of days utilized was significant at p=0.05 (Appendix A, Tables 72 and 73).
a> Table 24. Oviposition by 2 0 pairs of A. tristis held 4 weeks at five treatment temperatures.
Total Temp. Weekly Egg Product ion—^ Wk. No.Eggs (°C.) No Eggs Range Av 4: SD % Tt. No. Eggs % Hatch
1 1553 32.2 1013 1-98 50.6 + 28.0 65.2 89.2 26 . 7 494 0-52 24.7 + 17.3 31.8 96.9 25.6-18.3 41 0-23 2.0 + 5 .6 2.6 92.7 21.1 5 0-4 0.3 ± 0.9 0.4 100.0 12.8 0 - - - -
2 4709 32.2 1864 0-189 93.2 + 58.9 39.5 96.2 26.7 997 0-98 49 . 8 + 33.1 21.1 95.3 25.6-18.3 1449 8-148 72.4 + 33.9 30.8 90.1 21.1 399 0-75 20.0 + 22.5 8.5 95.2 12.8 6 0-6 0.3 ± 1.1 0.1 40.0
3 5458 32.2 1756 0-201 87.8 + 57.7 32.2 95.3 26.7 1601 0-140 80.0 + 41.6 29.3 96.4 25 .6-18.3 1370 5-134 68.5 + 33.8 25.1 86 . 3 21.1 729 0-92 36.4 + 27.6 13.1 90.4 12. 8 2 0-1 0.1 + 0.3 0.04 0.0
4 5040 32.2 1086 0-143 54.3 + 48.8 21.5 99.1 26. 7 1281 0-115 64.0 + 36.2 25.4 96.6 25.6-18.3 1858 3-188 92.9 ± 45 .1 36.9 86.1 21.1 815 0-103 40.7 + 30.1 16.2 98.2 12 .8 0 - - --
a/ An analysis of variance completed on the effect of temperature on weekly egg production and viability was significant at p=Q.05 (Appendix A, Tables 74-81).
• p 48 became more evenly distributed among those, pairs held at
32.2°C., 26.7°C. and 2 5.6-18.3°C. (Table 24). Egg produc tion by females held at 21.1°C. lagged behind the 3 latter temperatures; however, their egg production increased progressively each week (Table 24).
Results from the temperature-transfer study revealed that both temperature and transfer affected egg production.
Four groups of females, transferred for 7 days (1-7) to
12.8°C. dispensed with egg production, while control females continued ovipositing fertile eggs (Table 25). Females transferred from 12.8°C. to 25.6-18.3°C. produced 6 eggs, in comparison to control females producing no eggs (Table 2 5).
Apparently, short-termed exposures to warmer temperatures promote egg development and production.
Females transferred from 12.8°C. to their initial temperatures during the second temperature transfer (8-14) resumed egg production within 48 hrs. Comparisons completed within each temperature treatment showed that transferred females produced only 50% as many eggs as control females
(Table 25), with the exception of females held at 12.8°C.
Temperature also affected egg production during the second transfer with both control and transfer females held at temperatures above 21.1°C. producing more eggs than those maintained at lower temperatures. 49
Both control and transfer females were synovigenic,
ovipositing eggs on a daily basis. Females maintained at
temperatures above 12.8°C. normally deposited 11-15 eggs most frequently over a 24 hr. interval, while those held
at 12.8°C. seldom produced more than 1-5 eggs over a 24 hr.
interval (Table 26). Table 25. Egg production by 6 control and 6 transfer pairs of A. tristis held at each of four treatment temperatures.^/
Pair Temperature ( C.) Total No. Week Identity Initial Present Eggs Per Female % Hatch
1 Control 32 .2 32.2 700 116.7 95.0 2 Control 32 .2 32.2 615 102.5 99.9
1 Transfer 32.2 12.8 0 0.0 — 2 Transfer 12 .8 32.2 372 62.0 100.0
1 Control 26.7 26.7 670 111.7 99.0 2 Control 26.7 26.7 546 91.0 98.6
1 Transfer 26.7 12.8 0 0. 0 — 2 Transfer 12.8 26.7 338 56.3 98.1
1 Control 21.1 21.1 518 86 . 3 96.9 2 Control 21.1 21.1 512 85.3 99.2
1 Transfer 21.1 12 . 8 0 0.0 — 2 Transfer 12.8 21.1 305 50.8 94.8
1 Control 12.8 12.8 0 0 .0 2 Control 12.8 12.8 0 0.0 - 1 Transfer 12.8 25.6-18.3 6 1.0 100.0 2 Transfer 25.6-18.3 12.8 32 5.3 100.0
a/ An analysis of variance completed on the effects of temperature , transfer and temperature X transfer were significant at p=0. 05 (Appendix A, Tables 82-85).
cn O Table 26. The frequency of eggs produced over 24 hr. intervals by control and transfer female A. tristis held at 4 treatment temperatures.
Range of Frequency of Collections Percent Total Collection Temp. Eggs Treatment (Female) Treatment (Female) (°C. ) Collected Control Transfer Control Transfer
32.2 1-5 3 1 8.8 5.5 6-10 2 2 5.9 11.1 11-15 8 1 23.5 5.5 16-20 7 3 20.6 16.7 21-25 10 6 29.4 33.3 26-30 3 3 8.8 16.7 31-35 0 1 0.0 5.5 36-40 0 1 0.0 5 .5 41-45 1 0 2.9 0.0 26.7 1-5 8 5 20.5 21.7 6-10 3 7 7.7 30.4 11 = 15 12 4 30.8 17.4 16-20 6 2 15.4 8.7 21-25 7 4 17.9 17.4 26-30 3 1 7.7 4.3 21.1 1-5 8 6 20.0 21.4 6-10 7 9 17.5 32.1 11-15 11 8 27.5 28.6 16-20 8 3 20.0 10.7 21-25 3 1 7.5 3.6 26-30 3 1 7.5 3.6 12.8 1-5 0 2 0.0 50.0 6-10 0 1 0.0 25.0 11-15 0 0 0.0 0.0 16-20 0 1 0.0 25.0 cn 52
Effect Of Corn In The Diet Of A. Tristis On Oviposition
Methods and Materials
Adult A. tristis were observed feeding on particles of corn found in bovine feces during laboratory studies.
Hence, I was interested in learning if these particles of corn could provide sufficient nutrition to initiate production of viable eggs.
Twenty pairs each of 0-24 hr. old A. tristis were placed on 5 experimental diets (Table 27) for a 2 week period. After 2 weeks, each experimental diet was replaced by a control diet of two crushed face fly pupae daily and water. At the conclusion of each week, egg production was recorded and comparisons were completed to measure the effect of adult diet on egg production and viability.
Each pair of adults was placed in an individual 5 cm. plastic petri dish, lined with filter paper and held in a temperature chamber at 25.6°C.-14 hr. photophase and
18.3°C.-10 hr.scotophase, 30-50% R.H. All eggs collected were held at the latter temperature for 7 days to record viability.
At the conclusion of this study, a diet-transfer study was initiated. The purpose of this experiment was to evaluate the effects of experimental and control diets on egg production and viability. Twelve pairs of adults were 53
Table 27. Experimental diets on which A. tristis were held at 25.6°C.-14 hr. photophase and 18.3 C.- 10 hr. scotophase, 30-50% R.H.
Diet Composition
1 Water
2 High moisture corn
3 Feces removed from animal 2 299 (animal maintained on a diet of haylage and D 440 grain supplement)
4 Particles of corn removed from feces of animal number 2299
5 Feces removed from animal 1948 (animal maintained on a diet of alfalfa hay and D 369 grain supplement)
randomly selected from each diet combination. Six pairs per diet combination were maintained 2 weeks on the control diet, while the six remaining pairs were transferred back to their original experimental diet for 2 weeks. An analysis was completed at the end of each week to measure the effect of diet on egg production and viability. Environmental conditions were identical to those described in the first study.
Results
Aleochara tristis failed to produce eggs while being maintained on the 5 experimental diets (Table 28). However, 54 once their experimental diets were replaced with a diet of crushed face fly pupae and water, oviposition usually commenced within 2-3 days (Table 29). The length of time between the diet exchange and initial oviposition was affected by diet-combination (Table 29). Adults held on diet-combination 1 did not commence oviposition for 7-8 days, while those maintained on the 4 remaining diets usually commenced oviposition 2-4 days following the diet exchange (Table 29).
An analysis of egg production completed one and two weeks after the diet exchange (to crushed face fly pupae) showed that adults on diet combination 1 respectively average 40 and 2 0 fewer eggs per female than those on the
4 remaining diets (Table 28). Egg viability was not affected by diet-combination.
Results from the 14 day diet-transfer study revealed that females removed from a previous diet of crushed face fly pupae suspended egg production within 14 days (Table
30), and produced fewer eggs than control females (Table
31).
Females maintained on a diet of water suspended ovi position 5 days after the replacement of the control diet
(Table 30). Adults maintained on the 4 diets containing particles of corn and fecal material sustained oviposition
2-5 days longer than the former females (Table 30). Control Table 28. The effect of diet-combination on A. tristis oviposition at 25.60C.-1% hr. photophase and 18.3°C.-10 hr, scotophase, 30-50% R.H.
Diet Egg Production^./ Week Combination No. Eggs Av. ± SD % Hatch
Water 0 HMC5/, 0 2299-' . 0 CR2299-' 0 19 5 8-' 0
Water 0 -- HMC 0 -- 2299 0 -- CR2299 0 - - 1958 0 -- Water-CFP-^ 343 17.1 ± 17.0 98.8 HMC-CFP 1155 57.0 ± 33.0 96.0 2299-CFP 942 47.1 ± 39.1 96.8 CR2299-CFP 934 46.7 ± 33.9 95.9 1958-CFP 1113 55.6 + 36.9 91.5 Water-CFP• 12 7 6 63.8 ± 49.8 90.0 HMC-CFP 1766 88.3 ± 37.8 97.8 2299-CFP 1666 83.3 i 45.8 97.9 CR2299-CFP 1577 78.8 ± 50.7 97.5 1958-CFP 1848 92.4 ± 47.7 97.1
b/ 2299= diet of feces removed from animal number 2299. c/ CR2299= particles of corn removed from feces of animal number 2299. d/ 19 58= diet of feces removed from animal number 1958. e/ CFP= 3rd and 4th week diet replacement of crushed face fly pupae, f/ An analysis of variance completed on the effect of diet-combination on egg production was significant during week 3 at p=0.05 (Appendix A, Tables 86 and 87). Egg viability was not affected (Appendix A, Tables 88 and 89). CJ1 cn Table 29. The effect of diet-combination on length of adult A. tristis preoviposition period.
Preoviposition Period (Days )—^ Diet No. Diet-Combination—^ Range Mean ± SD
1 Water-crushed face fly 19-28 22.3 ± 4.3 pupae
2 High moisture corn- 16-28 17.6 ± 4.3 crushed face fly pupae
3 Feces from animal No. 2299- 16-28 18.4 + 3.6 crushed face fly pupae
4 Corn removed from feces 16-28 19.4 ± 4.4 animal No. 2299-crushed face fly pupae
5 Feces from animal No. 195 8- 16-28 18.7 ±4.1 crushed face fly pupae
a/ Maintained 14 days on experimental diet followed by a 14 day diet replacement of crushed face fly pupae. b/ An analysis of diet-combination on length of preoviposition was significant at p=0.05 (Appendix A, Table 90).
cn o> 57
.Table 30. Effect of experimental diets on suspension of oviposition of A. tristis maintained at 25.6 C. 14 hr. photophase and 18.3 C.-IO hr. scoto- phase, 30-50%.
Suspension of Oviposition (Days)—^ Diet Range A v . T SD
Water 4-7 5.5 ± 2.9
High moisture corn 2-12 8.0 + 3.5
Feces from animal 5-11 7.5 + 2.1 number 2299
Corn removed from 7-12 9.0 + 2.7 feces of animal number 22 99
Feces from animal 8-11 10.2 + 1.2 number 19 58
a/ An analysis of variance on the effect of diet on suspension of oviposition was significant at p=O.OS (Appendix A, Table 91).
females remained productive through weeks 1 and 2, re spectively, averaging 519 and 555.6 eggs per female (Table
32). Experimental females produced only 1/4 to 1/5 as many viable eggs as control females during week 1 (Table
31). Since all experimental females suspended oviposition within 12 days, few eggs were deposited by the latter during week 2 (Table 32). Table 31. Oviposition by 6 pairs of A. tristis maintained on each experimental and control diet at 2 5.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H. TT
Week Diet No. Eggs Range Av. ± SD % Hatch
1 Water , 43 3-16 7.1 ± 5.0 9.1 Control— 537 21-98 89.5 + 33.1 90.9
2 Water 0 Control 74 72-146 76.3 i 26.1 100.0
1 HMC-^ 80 2-21 11.4 i 7.5 11.3 Control 629 14-123 89.9 Î 35.7 88.3
2 HMC 41 0-15 5.4 + 6.1 5.4 Control 721 55-139 103.0 ± 25.3 94.6
1 2299-'^ 101 1-33 14.0 ± 17.2 16.4 Control 516 16-98 73.0 ± 30.4 83.6
2 2299 26 0-12 3.7 i 4.4 5.4 Control 458 47-89 65.4 + 17.2 94.6
cn 00 Table 31. Continued.
Oviposition— ' Week Diet No. Eggs Range Av. i; SD % Hatch
1 OR 2299-^ 130 6-40 18.6 + 13.7 23.3 Control 429 1-100 61.3 + 31.2 76.7
2 CR 2299 15 0-8 2.1 + 3.1 3.2 Control 455 57-123 87.9 + 22.2 96.8
1 1958-^ 127 6-33 19 .2 + 11.0 17.6 Control 593 20-108 84.7 ± 29.8 82.4
2 1958 36 0-24 5.1 + 8.9 5.9 Control 570 61-95 81.4 + 12.1 94.1
a/ Control: diet of crushed face fly pupae. b7 2299= diet of feces from animal number 2299 , c/ HMC= diet of high moisture corn. d/ CR2299= diet of corn removed from animal 22 99. e/ 1958= diet of feces from animal 1958. f/ An analysis of variance completed on the effect of diet on egg production was significant at p=0.05 for week 2 (Appendix A, Tables 92 and 93). Hatch was affected during week 2 (Appendix A, Tables 94 and 95). cn CD Table 32. Weekly oviposition by combined experimental females and control females held at 25.6°C.-14 hr. photophase and 18.3®C. 10 hr. scotophase, 30-50% R.H.
Week Treatment No. Eggs Range Av. ± SD -
1 Control— ^ 2595 428-629 519.0 t 92.1 Experimental^^ 481 43-130 96.2 ± 36.1
2 Control 2778 455-721 555.6 ± 109.0
Experimental 118 0-41 23.6 ± 16.5
a/ Control represents all females held as controls with each of the experimental females. b/ Experimental females represents all females combined from all five treatments. c/ An analysis of variance completed on the effect of control diet vs. experimental diet on egg production was significant at p=0.05 (Appendix A, Tables 96 and 97). d/ Average from a combination of 5 treatments (30 females).
cn o 61
Discussion Of Oviposition Studies
Oviposition studies completed with Aleochara tristis,
a staphylinid parasitoid of the face fly, agreed closely
with results from two related, species : Aleochara bilineata
Gy11. (Baryodma ontarionis Casey), a parasitoid of the
cabbage maggot (Hylemya brassicae (Bouche)) and Aleochara taeniata Erickson, a parasitoid of the housefly (Musca domestica Linn.).
A, bilineata females commenced oviposition within 48 hrs. of mating, averaging 15 eggs per day. Females normally deposited an average of 710 eggs during their
life time (72 days) with a maximum of 989 eggs (Calhoun
1953, Read 1962).
A. taeniata females began ovipositing 4-5 days after mating. The total number of eggs laid per female ranged from 163 to 639, with an average of 324 over an ovi position period of 90 days (White and Legner 1966). The maximum number of eggs laid in one day was 21. Thus, A. tristis productivity, averaging 500 eggs per female over an 84 day oviposition period, lies directly between that of A. bilineata and A. taeniata.
Aleochara species usually oviposited 10-20 eggs per day rather than depositing 2-3 clutches of 100 or more eggs and then suspending oviposition. The egg production strategy of A. tristis and related parasitoids may be explained 62
in a variety of ways. Price C1974) lists 5 factors necessary in defining an egg production strategy as
follows :
1. Probability of discovery or reaching the food
(host).
2. Availability of food in terms of its dispersion,
abundance and accessibility.
3. Survival of food item (host) during residence of
parasite.
4. Competition between members in the dispersal
phase and residential stage.
5. Effect of host resistance on survival of parasite.
Applying these factors to the relationship between A. tristis and its host (the face fly) may suggest some reasons as to why the parasitoid produced a few eggs daily over its life span.
First instar parasitoid larvae search in the vicinity of the dung pat for host pupae. The success of this activity is influenced by host abundance and availability.
Face fly larvae do not pupate within or beneath the manure pat. Instead, they migrate 0.3-6,4 meters prior to pupation (Jones 1969). Thus, first instar A. tristis larvae do not have easy access to the host and may expend part or all of their energy prior to reaching and attempting to parasitize the host. Also, the abundance of host pupae 63
is predetermined by larval mortality. Field studies
completed by Valiela (196 8) showed that up to 6 0% mortality
occurred in face fly larval populations which would
severely limit the number of available host pupae.
One advantage does exist for A. tristis in that the
calcified puparium of the face fly usually is resistant to
attack by predators and parasitoids, with exception to A.
tristis (Hair and Turner 1965, Burton and Turner 1968).
Thus, once a parasitoid larva enters the puparium, there is
good probability that it will complete development and
emerge as an adult.
In addition to Price (1974), Gadgil and Bossert (1970), explained the reproductive effort of organisms as follows :
greater availability of a resource will lead to a greater reproductive effort; second, the intrinsic rate of natural
increase (r ) reflects the environmental resistance to max which a species is habitually exposed (Pianka 1970).
Euceros frigidus Cress females oviposit 1-3 clutches
of 100-110 eggs within a 10.2 cm. radius of a large egg
population of sawflies (Tripp 1961). Hence, with easy
access to this abundant host population, E. frigidus responds by producing a large clutch of eggs. However, a large
parasitoid population is necessary because of larval mor
tality of the parasitized and non-parasitized host. Para
sitoid species attacking small and less accessible host
such as Pleolophus indistinctus, a sawfly cocoon parasitoid. 64
respond by producing only a few eggs at a time. This
ensures that maximum energy is available for continued
search and that the searching female is not overburdened
with eggs when she is unable to use them (Price 1970,
Price 19 73).
Price (1973) also suggested that the number of eggs
parasitic ichneumonids produced is closely related to the
stage of the host attacked. Thus, ichneumonids such as
Euceros frigidus attacking the larval stage produced
approximately 30 times more eggs than Pleolophus indistinc-
tus (Provancher) which attacked the cocoon stage.
Tinkle (196 9) studying the reproductive effort of
lizards showed that individual life expectancy altered egg production strategy. Short lived lizards usually laid multiple clutches of eggs while most long-lived lizards were single brooded.
Thus, the egg production strategy of A. tristis may be based on the following factors: (1) Exposed host pupae
are neither abundant nor easy to reach and parasitize.
(2) Parasites may reserve energy to search for additional
oviposition sites to deposit 10-15 eggs. (3) Parasites may not produce as many eggs since they parasitize the resis
tant host pupal stage. (4) With a life expectancy of 1 or more years (Drea 1966) it is adaptive for A. tristis to
oviposit a few eggs daily over their entire life expectancy
to maximize the chances of progeny survival. 65
Staphylinids in general usually deposited their eggs under the dead body of some animal or in some other place already provided with food, that is, in decaying animal or vegetable matter or wherever dipterous larvae are to be found (Mank 1923). This oviposition site was usually found by the olfactory sense of the female. Aleochara tristis females usually deposited their eggs in manure pats from animals maintained on a diet of alfalfa hay. The selection preference of females to these pats may be because of the pats attractiveness which is dependent on animal diet. Diet also affected pat odor, color and surface texture. These studies did not measure the effect of odor on pat attractiveness to Aleochara tristis; how ever, each pat had its own distinct odor and may have influenced A. tristis in its oviposition site selection.
The composition and surface texture of manure were de pendent upon animal diet. Manure samples taken from a animals primarily maintained on alfalfa hay contained large numbers of loose, fibrous particles. This type of surface allowed females to burrow beneath the fecal particles and to conceal their eggs from possible predators and parasites. Samples taken from animals maintained on corn supplements and corn silage were more compact, with reduced numbers of loose fiber. Females seldom concealed their eggs within these pats, but usually placed eggs in the soil beneath the pat or on the exposed pats’ surface. 66
The placement of parasitoid eggs by females influences egg survival and hatch, Parasitoid eggs placed within or on top of dung pats were more susceptible to disturbance than those beneath. Aphodius spp. and Sthaeridium spp. are early burrowing visitors to manure pats (Mohr 1943,
Garry and Wingo 1971, Kessler and Balsbaugh 1972). This type of activity causes parasitoid egg displacement and occasionally eggs are damaged. Also, eggs associated with the top of the dropping are more susceptible to dessication and predation than those within or beneath the dropping.
Five staphylinid predators of Diptera were collected during the summer of 1974 from bovine fecal droppings in
Wayne County, Wooster, Ohio and identified by Ian Moore^.
These include Philonthus longicornis Steph., P. stericinus
Gmel., P. rectangularis Sharp, Tachinus luridus Er. and
Hyponygrus fractcornis Mull. When they were exposed to eggs of both ^ tristis and the face fly, they consumed the latter eggs followed by eggs of A. tristis. Hence, staphylinid predators during a stress situation with food in short supply, will consume another predators eggs.
The placement of eggs on the surface of dung in some cases deprives 1st instar A. tristis larvae from searching
^ Ian Moore, Department of Entomology, University of California, Riverside 67
for a host. Occasionally, 4-5 day old manure pats become
overgrown with hyphae of fungi, and hatching first instar
larvae often become mechanically entangled in the mass of hyphae and die.
Thus, it is evident that the selection of a suitable
oviposition site is of great importance since it must ensure that the parasitoid eggs are adequately protected from the environment. A second aspect of this site selection is an available food source for the developing parasitoids.
It is advantageous that A. tristis "prefers" ovi positing in manure pats from animals maintained on alfalfa hay. Reports from Treece (1966) and Bay et al. (196 8) suggested that feces from these animals were likewise most attractive to face flies for oviposition, as measured by the total number of pupae produced. Thus, both the host and parasitoid prefer identical droppings for oviposition.
This type of synchronization allows the ovipositing para site to feed on available host eggs as well as providing first instar larvae close access to developing host pupae
surrounding the pat.
Aleochara tristis females maintained at 2 5.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase with relative humidity fluctuating between 30-50%, consistently produced eggs over their 84 days oviposition period. However, a number of variables were examined which affected egg 68 production and egg viability.
Female age and weight did not influence oviposition.
Regardless of these variables, females continued to ovi posit on a daily basis. In general, literature existing on senescence indicates that older females produce fewer eggs with reduced viability (Chapman 1971). Studies completed with Hippelates bishoppi Sabrosky and H. pallipes Loew
showed that egg viability decreased linearly with maternal age (Karandinos and Axtell 1972).
Studies on the effect of parental weight on fecundity and fertility are conflicting and species specific.
Shorey’s (1963) studies with Trichoplusia ni (Hubner) showed no definite correlation between parental weight and egg production, whereas work completed by Cheng (1972) with the dark-sided cutworm showed a positive correlation be tween female weight and egg production.
Male removal, temperature and adult diet also affected oviposition. Laboratory studies indicated that females require multiple matings to sustain oviposition. Females isolated from males produced fewer eggs than paired females. Similar results were reported by White and
Legner (1966) studying the life history of Aleochara taeniata, a parasitoid of the house fly. They observed that copulation must occur repeatedly if production of viable eggs is to be continued. Following exhaustion of 69 the sperm supply from the spermatheca, A. taeniata females produced a few non-viable eggs, after which oviposition ceased. Replenishment of the sperm supply renewed ovi position.
Female A. tristis suspended oviposition after being isolated from males for 5 weeks. However, after réintro duction of the male, copulation occurred within minutes, and oviposition resumed in 24-48 hrs. One female's egg production increased from 9 eggs prior to réintroduction of the male, to 94 eggs after the male was present 7 days.
Thus, females require multiple matings to sustain egg production. Additional work is needed in the area of mass release and the effect of male density on female oviposition behavior.
A. tristis encounters a variety of fluctuating tempera tures during its reproductive life. Since adults are associated with the bovine manure droppings and pasture areas surrounding the latter, it is necessary to expand on the relationship between the temperature of ambient air and this microhabitat. According to Hammer's (1941) measure ments of over 600 manure pats, maximal temperature in the surface of the dropping is reached simultaneously with the maximal temperature in the air at a height of 10 cm. The maximal temperature at the bottom of the pat is often reached 1-3 hrs. after the surface maximum is reached; this is explained by the poor heat conductance of the dung. The 70 minimal temperature in the surface of the dropping usually is slightly higher than air temperature at a height of 10 cm.
Since females seldom commenced ovipositing until temperatures reach 21.1°C.-25.6°C., I would expect con sistent egg production to begin in late May and continue through August. Also, females exposed to temperatures above 21.1°C. responded by producing twice as many eggs within a 24-48 hr. period than those maintained at lower temperatures. Thus, with face fly populations peaking in the warm months of July and August (Hammer 1941,
Teskey 1960, Teskey 1969), A. tristis females at this time can be expected to produce a large number of eggs. This allows more parasite larvae to enter the environment to search for a large population of host pupae. It is also advantageous that both A. tristis and its host (the face fly) reduce egg production during periods of moderate temperatures. This type of synchronization prevents the parasitoid from ovipositing a large number of eggs when host populations are unable to support the increased parasitoid population.
Results from the adult diet study revealed that female
A. tristis required face fly eggs and larvae in their diet to commence and sustain oviposition. Adults removed from a continuous diet of crushed face fly pupae suspended ovi position within 12 days. During the latter 12 day interval. 71 females seldom deposited more than 4-6 eggs per day.
In summary, female A. tristis have the capacity to oviposit 10-15 eggs daily for several months. However, oviposition was affected by air temperature, availability of face fly eggs and larvae and continuous male contact.
Also, egg development was influenced by climatic conditions, and egg survival was influenced by adult predators and scavengers associated with the bovine manure dropping. MORTALITY STUDIES
Effect Of Temperature On Survival Of Unfed Adult Aleochara
Tristis
Methods and Materials
Fifty pairs of 0-12 hr. old adults were held at each of 5 treatment temperatures: 32.2°C., 26.7°C., 25.6°C-14 hr, photophase and 18.3°C,-10 hr. scotophase, 21.1°C. and
15.6°C., i 0.07°C. Relative humidity fluctuated between
30-50%. Each pair was placed in a 5 cm. petri dish lined with unmoistened filter paper and was checked at 24 hr. intervals to determine adult mortality (Appendix B, Table
98).
Results
Results from this study showed that temperatures above 21.1°C. accelerated adult mortality (Table 33).
Adults maintained at 21.1°C, usually survived 4-5 days longer than adults held at 32.2°C. Also, 100% adult mortality occurred within 72 hrs. for A. tristis maintained at 32.2°C. In comparison, adults held at 21.1°C. lived up to 11 days (Table 33). Examination of Figure 4 reveals that males usually succumbed prior to females.
72 Table 33. The effect of temperature on the longevity of unfed adult A. tristis.
a/ Adult Longevity (Days) Males Females (°C.) Range Av. I SD Range Av. I SD
15.6 8-15 9.8 ± 1.9 7-15 12.0 ± 2.5
21.1 5-11 7.4 + 1.9 4-11 8.6 i 1.7
25.6-18.3 3-7 3.8 ± 1.1 1-6 4.4 i 1.3
26.7 3-7 4.3 ± 1.0 3-6 4.9 i 0.9
32.2 1-3 2.2 ± 0.6 1-3 2.5 ± 0.5
a/ An analysis of variance completed on the effect of temperature on male and female survival was significant at p=0.05 (Appendix B, Tables 99 and 100).
00 16
14
12
10 CO > 1 (0 Q
15.6 26.7 32.2 18 . 3
Temperature (°C.)
Figure 4 ; Effect of Temperature on Survival of Unfed -«3 Adult A. tristis. 75
Effect Of Temperature On Survival Of Unfed First Instar
A. Tristis Larvae
Methods and Materials
Ten replicates of ten 0-2 hr. old 1st instar larvae, placed in a petri dish lined with unmoistened filter paper,were held at each treatment temperature with a 14 hr. photophase: 32.2°C., 25.6°C., 25.6-18.3°C. , 21.1°C. and
15.6°C. ± G.G7°C. Relative humidity fluctuated between
3G-5G%. Petri dishes were examined at 24 hr. intervals to determine larval mortality (Appendix B, Table IGl).
Results
Results from this study revealed an inverse relation ship between temperature and larval longevity (Figure 5).
Decreasing temperatures prolonged larval longevity, allowing the parasitic larvae additional time to slowly search for host pupae at lower temperatures. Larvae exposed to 32.2°C. seldom survived 1/3 as long as those maintained at 21.1°C. (Table 34). 76
Table 34. The effect of temperature on the longevity of 1st instar A. tristis larvae.
Temperature First Instar Longevity (Days)S. (°C.) Range Av. ± SD
15.6 0 — 8 5.2 + 1.9
21.1 0-5 3.5 + 0.9
25.6-18.3 0-4 1.8 + 0.5
26.7 0-2 1.8 + 0.4
32.2 0-1 1.0 + 0.0
a/ An analysis of variance of the effect of temperature on larval survival was significant at p=0.05 (Appendix B, Table 102). 7
6
5
4 IT) Q
3
2
1
15.6 21.1 25.6 26,7 32.2 18.3 Temperature (°C.)
Figure 5 ; Effect of Temperature on Unfed First Instar Larvae
•>0 ' j 78
Discussion Of The Effect Of Temperature On The Longevity
Of Unfed Adult And First Instar A. Tristis Larvae
Adult and larval studies completed with A. tristis showed that extreme temperatures shortened their survival time. However, field populations of A^. tristis seldom encounter temperatures as high as 32.2°C. for extended periods of time.
Laboratory and field observations with A. tristis showed that adult behavior in some cases may aid in the prevention of early adult death. Adults exposed to excessive temperatures (26.7-32.2°C) in laboratory studies usually burrowed into the moist soil beneath the dung pat and remained there in akinesis, escaping death by immediate dessication. During field releases, I observed
A. tristis adults seeking shelter from the intense sunlight by burrowing underneath old dung pats. Also, Allee (1968) showed that unfed adult A. tristis survived 2-3 days longer at 27°C., 90-100% R. H. than those held at room temperature (21-27°C.) and humidity (40-70%). Thus, adults seeking out moist areas will increase their chance of survival when available food sources are in short supply.
Behavioral responses of first instar A. tristis larvae were not studied. However, laboratory observations showed that unfed larvae maintained at 12.1°C. and 15.6°C. were 79 less active than those maintained at temperatures above
21.1°C. Thus, a reduction in larval activity enhances its ability to survive during unfavorable environmental conditions, including extremely low temperatures. ADULT A. TRISTIS SIZE EFFECT STUDIES
Relationship Between The Weight And Sex Of Adult A. Tristis
Methods and Materials
Four-hundred parasitized face fly pupae were placed in individual shell vials, stoppered with cotton, and held at room temperature (21°C.) and humidity (40-60%). After each adult emergence, the parasite was anesthetized with
COg, weighed and sexed (Appendix 0, Table 103).
Results
Three-hundred thirty-five adult parasites, 176 males and 158 females, emerged from their parasitized host puparia. The average weight for both sexes was 3.9 t 1.4 mg., and no relationship existed between adult weight and adult sex ratio (Appendix C, Table 104).
Correlation Between Host Pupal Size and Adult Parasite
Weight and Sex Ratio
Methods and Materials
One hundred eighty 48-hr. old face fly pupae were randomly selected and weighed. Each pupa was placed in a soil-filled diet cup with one 0-2 hr. old first instar
80 81 parasite larva and held at room temperature until the
adult parasite emerged. After each emergence, the adult was anesthetized with COg; weighed and sexed.
Results
Forty four adult parasites successfully completed development and emerged from their parasitized host pupae
(Appendix C, Table 105). A positive correlation existed between adult weight and host pupa weight, with increasing host pupal size favoring the emergence of larger adult parasitoids (Appendix C, Table 108). However, no correlation existed between host pupal size and adult sex ratio or adult size and adult sex ratio (Appendix C, Table
106).
Discussion Of Adult Size Effect Studies
In general, publications available on the effect of host size on parasite sex ratio are conflicting and species-specific. Extensive consideration has been given to species of Hymenoptera. Studies conducted with Nasonia vitripennis Walker, a parasite of the house fly, showed no relationship between host size and parasite sex ratio
(Wylie 1967). However, field and laboratory studies completed with Itoplectis species showed that usually
females were recovered from large host cocoons and males from small host cocoons (Clausen 1939). Clausen's (1939) 82 explanation for this phenomenon is that large hosts were attacked by fertile females and small hosts were attacked by unfertile females.
Flanders (19 39, 1964, 1965) has also done extensive work with the sexuality and sex ratios of Hymenoptera. He states that "with mated females, discontinuity in egg fertilization appears to be an effect either of an excessive rate of egg deposition or of a differential responsiveness of the spermathecal gland to stimuli derived from the medium (host) upon which eggs were to be deposited." Also, the differential response of the Hymenopterous spermathecal gland is effected either by difference in sensitivity
(thresholds of stimulation) to constant environmental stimuli or by variations in the intensities of such stimuli.
Hence, in the latter case, Itoplectis females may have received favorable stimuli from the large host cocoons which resulted in the deposition of fertile eggs.
Female A. tristis do not oviposit until they are mated.
Thus, Clausen's explanation of sex ratio's dependence on host size effect on mated-unmated females does not apply to
A. tristis. Regardless of host size or adult parasitoid size, the ultimate sex ratio remains 1:1 in populations of
A. tristis. Also, since field recovered pupae of the face fly usually weighed 25-30 mg., A. tristis larvae successful in host entrance and development will emerge as fairly large free-living adult predators (Valiela 1968). PARASITIZATION STUDIES
Effect Of Temperature And Host Condition On Parasitization
Of Face Fly Pupae By Aleochara Tristis Larvae
Methods and Materials
Ten 0-2 hr. old first instar A. tristis larvae were
exposed for 60 hrs. to 10 M-8 hr. old face fly pupae placed
in a petri dish lined with sterilized soil. Eight repli
cates were completed for each host pupal treatment
(Treatment 1 : all exposed host pupae were non-parasitized;
Treatment 2 ; all exposed host were parasitizedj Treatment
2: 5 hosts were parasitized and 5 hosts were non-parasitiz
ed) at each of 3 treatment temperatures; 32.2°C., 25.6°C.-
14 hr. photophase and 18.3°C.-10 hr. scotophase and 21.1^0.,
Î 0.07°C. Relative humidity fluctuated between 30-50%.
After 6 0 hrs, each pupa was dissected and the number of
parasite larvae recovered were recorded.
Parasitized host pupae were obtained by exposing one
24 hr. old host to one 0-2 hr. first instar parasite larva
for 2 0 hrs. At the end of 20 hrs. each host was examined
under a stereo-dissecting microscope to observe the absence
or presence of the parasite. Those containing one larva per pupa were used in treatments 2 and 3 as parasitized hosts.
83 84
Results
Cumulative results from treatments one, two and three
indicated that both host condition and temperature affected rates of parasitization. First instar larvae were most
successful in parasitizing host pupae within treatment one,
in which all exposed hosts were non-parasitized. However, a comparison of means within treatment one showed no difference in rates of parasitism between the three temperatures (Table 35).
Parasite larvae exposed to parasitized hosts in treatment two, with exception of those held at 21.1°C., parasitized only 1/2 to 1/3 as many hosts as they did in treatment one. Also, two of the treatment 2 means were
significantly different (Table 35). When parasite larvae were given a choice of host conditions in treatment three, they always parasitized non-parasitized hosts at a higher rate than parasitized hosts (Table 35). Also, larvae were most efficient within treatment three when maintained at
25.6-18.3°C., with parasites entering non-parasitized host
7 times more frequently than parasitized host (Table 35).
Rates of superparasitism also were influenced by temperature and host condition. Host pupae maintained at
21.1°C. were superparasitized more frequently within each treatment than those held at 32.2°c. and 25.6-18.3°c. Table 35. Effect of host condition (parasitized versus non-parasitized host) and temperature on the rate of parasitization of face fly pupae by A. tristis larvae.
______Average Percent Parasitization—^______Treatment 1 . , Treatment 2 , Treatment 3 (NP/P)______Temperature (Non-Para. Host)— (Para. Host)— (Non-Para) (Para)., (°C.) Av. ± SD-' Av. i SD- Av. ± SDd/ Ay. ± SD^.'
32.2 38.7+15.5-^ 22.5 + 11.6-^-^ 22.5 ± 19.8^/ 17.5 t 27.1-^-/
25.6-18.3 37.5 t 10.3-^ 20.0 ± 13.1-^ 37.5 ± 29.1^/ 5.0 ± %.1- ■
21.1 40.0 + 1 ,h- 36.2 ± 10.6-^ 37.5 ± 16.7^/ 32.5 ± 23.7^/
a/ An analysis of variance completed on the effect of host condition and temperature on % parasitization was significant at p=0.05 (Appendix D, Table 108). b/ An analysis of variance completed on the effect of temperature on rate of parasitization within treatment one (non-para) was not significant at p=0.05 (Appendix D, Table 109). c/ An analysis of variance completed on the effect of temperature on rate of parasitization within treatment two (para.) was significant at p=0.05 (Appendix D, 110). d/ Means followed by the same letter within each category are not significantly different at p=0.05 (Duncan's New Multiple Range Test).
00 cn 86
(Table 36). No superparasitism occurred within treatment three where parasitized host were exposed to A. tristis larvae at 25.6-18.3°C. When superparasitism occurred, as many as 4-5 parasite larvae were recovered from a single host puparium. However, seldom was more than one parasite alive after 60 hrs. exposure within the host (Appendix D,
Table 107). Table 36. Effect of host condition (parasitized versus non-parasitized host) and temperature on the rate of superparasitization of face fly pupae by A . tristis larvae.
Average Percent Superparasitization—^ Treatment 1 Treatment 2 Treatment 3 (NP/P) Temperature (Non-Para) (Para.T, (Non-Para) (Para.) (°C. ) Av. t SDb/ Av. + SD^/ Av. i SD(NP)-' Av. i SD(P)-'
32 .2 3.7 i 5.2-^-^ 3.8 i 5.2-^ 2.5 + 7.1^/ 2,5 + 7.1-^
25.6-18.3 1.2 i 3.5-^ 7.5 + 7.1^/ 2.5 + 7.1^/ 0 t 0-^
21.1 15,0 + 9,3^/ 11.3 i 8.3^/ 10.0 Î 10.7^/ 7.5 + 10.3^/
a/ An analysis of variance completed on the effect of host condition and temperature on rate of superparasitization was significant at p=0.05 (Appendix D, Table 111). b/ Means followed by the same letter within each category are not significantly different at p=0.,05 (Duncan's New Multiple Range Test).
CO 88
Effect Of Soil Moisture And Host Condition On Parasitization
Of Face Fly Pupae By Aleochara Tristis Larvae
Methods and Materials
The objective of this experiment was to evaluate the effect of soil moisture and host condition on rate of parasitization and superparasitization. Ten 0-2 hr. old first instar A. tristis larvae were exposed for 80 hrs. to
10 48 hr. old face fly pupae placed in a petri dish lined with soil. Eight replicates were completed for each host pupal treatment (Treatment 1: all exposed host pupae were non-parasitized; Treatment 2 ; all exposed host pupae were parasitized; Treatment 3 ; 5 hosts were parasitized and 5 hosts were non-parasitized) at each soil moisture (Table 37).
All replicates were held in a temperature chamber main tained at 25.6°C.-14 hr. photophase and 18.3°C. scotophase,
30-50% R.H.
At the end of 60 hrs. each host was dissected to record the number of parasite larvae present.
Parasitized host pupae were obtained by exposing one
24 hr. old host to one 0-2 hr. first instar parasite larvae for 20 hrs. At the end of 20 hrs. each host was examined under a stereo-dissecting microscope to observe the absence or presence of the parasite. Hosts containing one larva per pupa were used in treatments 2 and 3 as parasitized hosts. 89
Table 37. Five soil moisture treatments used in this experiment.
Experimental Corrected Soil—^ Soil Moisture Moisture (Av. ± SD)
Air Dry (3.5%) 3.2 + 0.02%
9.0% 15.1 i 0.5%
20.0% 20.3 t 0.2%
31.0% 31.2 ± 0.3%
Saturated (40%) 41.9 i 1.2%
a/ Each corrected soil moisture value is an average of 4-100 gram samples from each moisture level (Appendix D, Table 112). 90
Each soil moisture was obtained by mixing sterilized air-dried soil, previously held at 48 hrs. at 17.8°C., with the correct amount of snow (grams). After mixing, the soil was placed in a cooler held at 17.8°C. for 24 hrs. Then the soil was removed and held 12 hrs. at room temperature
(21°C.) after which four-100 gram samples were taken from each soil moisture mixture and baked 48 hrs. at 107°C. in a Precision P. S. Thelco Oven . At the end of 48 hrs., each sample was removed, weighed and the corrected soil moisture was calculated (Table 37).
Results
The data from each series of treatments are found in
Tables 38 and 39. Results indicated that parasite larvae were most efficient when exposed to non-parasitized hosts through the first 3 soil moisture levels within treatments
1 and 3 (Table 38). Within treatment 1, the rate of parasitization remained above 35% through the first three soil moisture levels, followed by a significant reduction in parasitism at the 31.2% and 41.9% moisture levels
(Table 38).
Parasite larvae were not successful in parasitizing hosts when they were exposed to only parasitized hosts
(Treatment 2). A comparison between treatment 1 and
Precision P.S. Thelco Oven (Harshaw Scientific, Harshaw Chemical Co.) Cleveland, Ohio 91 treatment 2 showed that host condition severely affected the number of hosts parasitized. When parasite larvae were given a choice of both host conditions within treatment 3, they responded by parasitizing non-parasitized hosts 5-10 times more frequently than parasitized hosts at the first
3 soil moistures. Parasites remained ineffective at the
31.2% and M-1.9% moisture levels; however, when parasitism occurred they usually selected non-parasitized hosts over parasitized hosts (Table 38).
Occasionally, superparasitism occurred; however, neither host condition nor soil moisture influenced this type of activity (Table 39). When superparasitism occurred, seldom was more than one larva alive per host after 60 hrs. exposure within the host pupa (Appendix D,
Table 113). Table 38. Influence of soil moisture and host condition on rate of parasitization of face fly pupae by first instar A. tristis larvae
Average Percent Parasitization—'T Treatment 1 Treatment 2 Treatment 3 (NP/P) Soil Moisture (Non-Para.) (Para. , (Non-Para. ), , (Para. ) ^ (%) Av. ± SD£/ Av. i SD Av. i SD(NP)- Av. i SD(P)-
Air Dry 38.7 t 8.sa/b/Ç/ 6.2 + 7. 4^/2/ 52.5 + 10.3-^-^ 2.5 + 7.1^/
15 .1 45.0 + 17 .7-^ 15.0 + 10 .1- 55.0 + 27.8^/-/ 2.5 + 7.1-^ 23.3^/b/ 20.3 42.5 + 19. 8-^-^ 15.0 + 7.5-^ 55.0 + 12.5 + 10.3^/
31.2 17.5 + 15.8-/-/ 5.0 ± 1 .B- 27.5 + 18 .3-^-^ 10.0 + 18.5-^
41.9 13.7 + 13.0^/ 8.2 + 7. ifb/c/ 2.5 + 7.1-^ 2.5 + 7.12/
a/ An analysis of variance completed on data from all three treatments showed that both host condition and soil moisture significantly affect the rate of parasitization at p=0.05 (Appendix D, Table 114). b/ Means followed by the same letter within each category are not significantly different at p=0.'05 (Duncan’s New Multiple Range Test).
CO ro Table 39. Influence of soil moisture and host condition on rate of super parasitization of face fly pupae by first instar A. tristis larvae.
______Average Percent Superparasitization— ______Treatment 1 Treatment 2 Treatment 3 (NP/P) Soil Moisture (Non--Para.) (Para. (Non- Para.). , (Para (%) Av. ± SDk/ Av. i SD-^ Av. ± SD(NP)2' Av. i SD(P)k/
Air Dry 2.5 + 4.6^/ 1.3 i 3. 52/b/ 4.4 + 8. gk/G/É/ 0 ± o2/
15.1 2.5 + 4.6^/ 10.0 ± 7.62/ 1.3 + 6. O^/d/ 0 + 02/
20.3 1.3 + 3.52/ 3.8 ± 5.22/b/ 5.0 + g.2S/b/c/d/ 0 + 02/
31.2 3.8 + 5.22/ 3.8 ± 5.22/b/ 10.0 + 15.1^/ 0 + o2/
41.9 0 + 02/ 0 i ok/ 0 + oi/ 2.5 + 7.l2/
a/ An analysis of variance completed on data from all three treatments showed that neither host condition nor soil moisture significantly affected the rate of superparasitization at p=0.05 (Appendix D, Table 115). b/ Means followed by the same letter within each category are not significantly different at p= 0.0,5 (Duncan's New Multiple Range Test).
(Û CO 94
Effect Of Host .Pupal Size On The Rate Of Parasitization Of
Face Fly Pupae By A. Tristis Larvae
Methods and Materials
This experiment was undertaken to evaluate the effect of host pupal size on parasite host selection and rate of parasitization. Ten 0*-2 hr. old first instar A. tristis larvae were exposed 60 hrs. to 10 48 hr. old face fly pupae placed in a petri dish lined with sterilized soil.
Ten replicates were completed for each host treatment
(Treatment 1; exposed hosts were selected as small (group 1)
(Table 40); Treatment 2: exposed hosts were selected as large (group 2) (Table 40); Treatment 3: 5 hosts were from group 1 and 5 hosts were from group 2). All host treatments were held in a temperature chamber maintained at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H.
At the end of 60 hrs. each pupa was dissected to determine the number of larvae per host.
Results
The cumulative data from all three treatments indi cated that host size affected parasite selection and rates of parasitization. When parasitoids were given a choice of host sizes in treatment 3, large hosts were parasitized
2.5 times more frequently than small hosts. However, when each group was exposed separately to A. tristis no differ ence was observed in the rate of parasitization (Table 41). Table 40. Size of host pupae in group one and group two.
Group Weight (mg)— Length (mm)—^ Width (mm)^/ Size Range Av. t SD Range Av. I SD Range Av. I SD
One 4.7-17.9 12.9 ± 3.7 4.3-5.6 4.9 i 0.3 1.3-2 .1 1.8 i 0.2 (small)
Two 19.7-36.3 28.3 i 4.7 5.4-7 .4 6.3 i 6.3 2 .2-3.4 2.7 ± 0.3 (large)
a/ An analysis of variance completed on the effect of weight, length and width between groups 1 (Appendix D, Table 116) and 2 (Appendix D, Table 117) were significantly different at p=0.05 (Appendix D, Tables 118, 119 and 120).
to cn 96
Rates of superparasitization also were influenced by host size. Regardless of the treatment, large hosts were always superparasitized more often than small hosts. No hosts were superparasitized in treatment 1, in comparison to 12% superparasitized in treatment 2. Hence, host size affected rates of parasitization as well as rates of superparasitization,
Table 41. Effect of host size on rates of parasitization and superparasitization of face fly pupae by A. tristis larvae.
Host Av. %- Av. t SD %- Treatment Parasitization Superparasitization
+ One (small) 36.6 9.7 -
Two (large) 39.0 + 9.9 12.0
Three (combination)
Group 1 (small) 22.0 + 22.0 2.0 ± 6.3
Group 2 (large) 52 .0 + 19.3 8.0 i 14.0
a/ An analysis of variance completed on data from all three treatments indicated that host size affect rates of parasitization and superparasitization (Appendix D, Tables 121 and 122). 97
Effect Of Host Density And Parasite Density On Rates Of
Parasitization Of Face Fly Pupae By Aleochara Tristis
Methods and Materials
This experiment was designed to measure the effect of host density and parasite density on parasite searching efficiency and rates of parasitization. Ten 0-2 hr. old first instar A. tristis larvae were exposed for 60 hrs. to three host densities of 10, 20 and 30 hosts (48-hr. old), placed in a petri dish lined with sterilized soil. Also, ten 48-hr. old host pupae were exposed for 80 hrs. to 3 parasite densities of 10, 20 and 30 0-2 hr. old first instar A. tristis larvae, placed in a petri dish lined with sterilized soil. At the end of 6 0 hrs. each pupa was dissected to record the number of parasites present per host.
Eight replicates were completed for each host and parasite density. All replicates were held in a temperature chamber maintained at 25.6°C.-14 hr. photophase and 18.3°C.-
10 hr. scotophase, 30-50% R.H.
Results
Both host density and parasite density affected parasite efficiency and rates of parasitization. The rate of parasitization was inversely dependent on host density, with parasitism decreasing from 37.5% to 17.9% with in creasing host density (Table 42). However, larval Table 42. The effect of host density on parasitization and super parasitization of face fly pupae by A. tristis larvae
Host Percent Parasitization—V , Percent Superparasitization-/, Density No. Host Para. Av. i SD— No. Host Superpara. Av. i SD—
10 30/80 37.5 t 10.3^/ 1/80 1.2 ± 3.5-/
20 45/160 28.1 ± 8.4-^ 4/160 2.5 i 2.7-/
30 43/240 17.9 + 3.1-/ 3/240 1.2 ± 2.4-/
a/ An analysis of variance of the effect of host density on rate of parasitization was significant at p=0.05 (Appendix D, Table 123). Super parasitization was not affected by host density (Appendix D, Table 124). b/ Means followed by the same letter within each category are not significantly different at p=0.05 (Duncan’s New Multiple Range Test).
CO 00 99 efficiency was directly dependent on increasing host density, as it increased from 38,7% at a host density of
10 to 61.0% at a host density of 20 (Table 44). No difference was observed in larval efficiency as host density increased from 20 to 30 (Table 44). Rates of superparasitism were not affected by increasing host density (Table 42).
In general, rates of parasitization were directly dependent on increasing parasite density, increasing from
37.5% to 7 0.0% (Table 43). Larval efficiency decreased
10% as the parasite density increased from 2 0-30 (Table
45). Also, the rate of superparasitism was directly de pendent on increasing parasite density as it increased from 22.5% to 33.7% (Table 43). Thus, larvae were most efficient at a hostrparasite ratio of 2:1. Table 43. The effect of parasite density on parasitization and super parasitization of face fly pupae by A. tristis larvae.
Parasite Percent Parasitization— •. , Percent Superparasitization—/ Density No. Host Para. A v . ± SD- No. Host Superpara. Av . ± SD-
10 30/80 37.5 + 10.3-^ 1/80 1.2 ± 3.5-/
20 56/80 70.0 + 11.9-/ 18/80 22 .5± 10.3-/
30 56/80 70.0 + 17.7-^ 27/80 33.7 + 22.0-/ a/ An analysis of variance of the effect of parasite density on rate of parasitization and superparasitization was significant at p=0.05 (Appendix D, Tables 125 and 126). b/ Means followed by the same letter within each category are not significantly different at p=0.05 (Duncan’s New Multiple Range Test),
o o 101
Table 44. The effect of host density on larval efficiency in parasitizing face fly pupae.
a/ Host Larval Efficiency—' b/ Density No. Larvae Entered % Larvae Entered ± SD—'
10 31/80 38.7 ± 11.2- 20 49/80 61.0 i 21.0^/ 30 46/80 57.5 + 14.9-^
a/ An analysis of variance of the effect of host density on larval efficiency was significant at p=0.0 5 (Appendix D, Table 127). b/ Means followed by the same letter within each category are not significantly different at p=0.05 (Duncan’s New Mulitple Range Test).
Table 45. The effect of parasite density on larval effi ciency in parasitizing face fly pupae.
a/ Parasite Larval Efficiency—' •b/ Density No. Larvae Entered Larvae Entered ± SD—
10 31/80 38.7 ± 11.2-^ 20 80/160 50.0 + 13.4-/ 30 88/240 40.8 + 13.3-/
a/ An analysis of variance of the effect of parasite density on larval efficiency was not significant at p=0.05 (Appendix D, Table 128). b/ Means followed by the same letter within each category are not significantly different at p=0.05 (Duncan's New Multiple Range Test). 102
Effect Of Host Pupal Location On Rate Of Parasitization By
A. Tristis Larvae
Methods and Materials
This experiment was conducted to evaluate the ability
of first instar larvae to locate and successfully parasitize host pupae located at 3 soil depths. Parasites were exposed to these depths as follows ;
Treatment 1; One hundred 48-hr. old host pupae
were evenly distributed in a circle with a 30 cm.
radius in a 60 x 75 cm. plastic container lined
with sterilized soil. These were then covered with
a small quantity of soil so they would not be
visible to the searching parasite larvae (soil
covered). Then 50 0-2 hr. old first instar
larvae were exposed 60 hrs. to the pupae. At the
completion of 60 hrs. each pupa was dissected and
the number of parasite larvae present was recorded.
Treatment 2 ; The identical procedure was followed
as described in treatment 1, except hosts were
located 1/2" below the soil surface.
Treatment 3 : The identical procedure was followed
as described in treatment 1, except hosts were
located 1" below the soil surface.
Treatment 4 : One hundred face fly pupae were
located at each depth within the same container and 103
exposed for 60 hrs. to 150 first instar parasite
larvae.
Pour replicates were completed for each treatment at room temperature (25.6°C.) and humidity (.40-60%).
Results
A comparison of results from treatments 1, 2 and 3 showed no difference in rates of parasitization or super parasitization when A. tristis were exposed to each depth separately. However, when given a choice between host locations within treatment 4, the searching preferences of
A. tristis were very significant (Table 46). Parasites were successful in parasitizing 43.4% of the hosts located
1" below the soil in comparison to 2% at 1/2" and 25.2% at the soil covered location. Also, superparasitism was affected by host location within treatment 4, with hosts located 1" below the surface of the soil superparasitized
3 times more frequently than those located at the two remaining locations (Table 46). Table 46. The effect of host pupal location on rate of parasitization and superparasitization of face fly pupae by A. tristis larvae.
ay Host Percent Parasitization—"a7 Percent Superparasitization—' Location A v . ± SD Av. + SD
Treat. 1— 28.0 i 3.48 0.5 ± 0.6 (Soil covered)
Treat. 2-^ 25.0 i 1.6 0.2 + 0.5 (1/2")
Treat. 3—^ 23.9i 3.1 0.7 + 0.9 (1")
Treat. 4-^ (Combination Soil Covered 25.2 + 19.7 0.5 + 0.6 1/2" 2.0 ± 1.8 0.0 1" 43.4 ± 7.2 3.8 + 1.8
a/ An analysis of variance of the effect of host location on paras itization and superparasitization from the combined treatments was s ignificant at p=0.05 (Appendix D, Tables 12 9 and 130). b/ An analysis of variance of the effect of host location on parasitization and superparasitization from treatments 1, 2 and 3 was not significant at p=G.05 (Appendix D, Tables 131 and 132). c/ An analysis of variance of the effect of host location on parasitization and superparasitization within treatment 4 was significant at p=0.05 (Appendix D, Tables 133 and 134).
M o -p 105
Discussion Of Parasitization Studies
A number of factors significantly influenced the effectiveness of an Aleochara tristis larva in its search, location, acceptance and successful parasitization of a host face fly puparium. These factors are divided into two categories; environmental factors and host-parasitoid associated factors.
It is well documented that weather and climate will affect the behavior of insects. Two environmental factors which influenced the success of A. tristis included tempera ture and soil moisture. First instar larvae, without regard to host condition, were highly successful in parasitizing hosts held at 21.1°C. Rates of parasitism declined when parasites and hosts were exposed to tempera tures above 21.1°C. This may be dependent on the effect of temperature on larval survival. Results from first instar larval survival studies showed that larval longevity was directly dependent on decreasing temperature. Larvae exposed to 21.1^C. survived for 120 hrs., in comparison to those maintained at 32.2°C. succumbing within 24 hrs.
Thus, parasitism may be limited by extreme temperatures because of their effect on early larval mortality, which in turn reduces the amount of time available for the parasite to search and gain entrance into its host. Hence, A. tristis, requiring 15-2 0 hrs. to enter the host in 106 laboratory experiments, were most effective in parasitizing hosts held at 21.1°C. due to extended larval survival.
First instar larvae of two related parasitoids are also affected by temperature, Larvae of A. taeniata require several hours to gain entrance to a housefly puparium, and when larvae were held at 23.8°C. and 99% R.H. ,
50% of them died within 84 hrs. (White and Legner 1966).
A. bilineata larvae were less susceptible to the effect of temperature, and when they were held at 2 3.8°C.-75% R.H.,
50% of the larvae successfully survived for 9 days and 100% larval mortality was not recorded for 19 days (Calhoun 1953),
Thus, it appears that temperature limits the success of
A. tristis and related species in parasitizing their hosts.
Temperature also affected superparasitism, with 10-15% more hosts superparasitized at 21.1°C. than those main tained at 32.2°C. and 25.6°C.-14 hr. photophase and 18.3°C.-
10 hr. scotophase, 30-50% R.H. However, parasites in the field seldom are limited to searching an area the size of a petri dish, so this type of behavior may not occur in the field. Similar results in reference to superpara sitism were reported by White and Legner (19 56) studying the behavior of A. taeniata and Calhoun (19 53) studying
A. bilineata larvae.
In addition to temperature, soil moisture retarded the searching efficiency of first instar A. tristis larvae. 107
Parasite larvae were successful in parasitizing hosts main tained on substrates with soil moistures ranging from
3.2-20.3%. However, larvae searching over a substrate with a 31.2% or 41.9% soil moisture were not effective in parasitizing hosts. First instar larvae became immobilized in the moist soil and were unable to gain footing and eventually died. Hence, in the event of an intense rain fall, it is highly probable that the searching efficiency of A. tristis may be severely reduced.
Four host-parasitoid associated factors influenced the success of A. tristis larvae in parasitizing face fly pupae. These included exposed host condition (non parasitized versus parasitized host), host size, host: parasite density and host location. A. tristis exposed to parasitized and non-parasitized hosts, in some cases, were able to discriminate between the two. This type of be havior is quite common among Hymenoptera, where it prevents the parasitoid from attacking a potential host that was previously parasitized. Salt (1937), working with the egg parasitoid Trichogramma evanescens, Westw. was the first to report that female parasitoids left a factor that inhibited further attack. Also, Price (1970) observed that parasitic female insects of the genera Pleophus, Endaoys and Mastrus (Ichneumonids) searching ground cover for hosts, avoided areas previously inspected by females. 108
Hence, this recognition and discriminatory response to female "trail odors" improves the utilization of the host resource by a parasite population.
The stimuli important in A. tristis's discriminatory behavior are not known. However, in my studies they were most effective in recognizing parasitized hosts held at
25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase on substrates with soil moistures ranging between 3.2-2 0.3%.
A number of factors may function as stimuli in A. tristis's discriminatory behavior and may include host color, release of a host chemical or kairomone, utilization of host move ment and sound, parasite’s sense of touch, parasite’s use of marking pheromones and the evaporation of an external odor or marking pheromone.
In some instances host color influences the discrimi natory behavior of parasites. Takahaski and Pimentel
(1967) reported that Nasonia vitripennis Walker, given a choice between black and normally brown-host housefly pupae, preferred parasitizing the abnormal black pupae. Hence,
Aleochara tristis larvae exposed to parasitized hosts may be influenced by their coloration. Non-parasitized 48-hr. old hosts normally are white, whereas parasitized hosts appear brown in spots because of the build up of detritus from the feeding parasite within the host puparium. Thus, coloration may assist the parasite in discriminating between parasitized and non-parasitized hosts. 109
In addition to host color, the host pupa may release some type of chemical or kairomone which attracts the parasite to the host. Fuldner (1960) showed that Aleochara curtula Goeze responded to a chloroform-extractable material from the puparia of Calliphora erythrocephala
Meigen, which serves as an orientation stimulus determining where the entrance hole is made by the attacking parasite.
A. tristis also may be influenced by this type of orien tation. However, the release and makeup of this chemical
(kairomone) may be adulterated by the entrance of an A. tristis larva. Thus, a parasite larva examining the surface of a parasitized host may be driven away because of possible changes in the released host chemical, no longer making it attractive to the parasite.
Some parasitoids utilize a host's movement and sound in determining its acceptance (Vinson 1976). A. tristis larvae examining a parasitized host may be influenced by movements and sounds eminating from a parasite larvae feeding within the host puparium. Thus, this type of stimulus may deter a second parasite from entering the parasitized host. Also, the movement and sounds from the host may be intensified by increasing temperatures. Larvae held at 25.6-18.3°C. and 32.2°C. may be feeding and developing at a faster rate within the host than those maintained at 21.1°C. Hence, sound intensification from the former host may result in a reduction of superparasitism 110
of hosts maintained at temperatures above 21.1°C.
The sense of touch also may aid A, tristis larvae in
discriminating between parasitized and non-parasitized host. An indentation remains on the surface of the host
puparium after the entrance hole is sealed by the parasite.
This latter indentation may enable the parasite larvae to
discriminate between a parasitized and non-parasitized host, reducing multiple entry and subsequent waste of parasite progeny.
At present, the most popular theory regarding dis
criminatory behavior centers around parasite marking and
trail pheromones (Vinson 1976). In the process of sealing the entrance hole, A. tristis larvae may release a chemical which marks the parasitized host as unfit for larval entrance. Thus, A. tristis responding to this chemical will search for a non-parasitized host.
Temperature also may influence the release and effectiveness of trail or marking pheromones. Results
indicated that larvae were most efficient at 25.6°C.-1‘+ hr. photophase and 18.3°C.-10 hr. scotophase, 30-50% R.H.
Perhaps, temperatures above 21.1°C. enhance the loss and evaporation of the pheromone, while temperatures below
21.1°C. are insufficient to initiate release of the pheromone, or these temperatures may affect the evaporation
of the chemical.
Soil moisture also may influence the effectiveness of Ill the chemical. If trail marking pheromones were released by larvae upon the substrate they were searching, it may be diluted by excessive moisture in the soil. Thus, tempera ture and soil moisture may influence the effectiveness of the pheromone.
Host size, in some cases, influenced the parasite’s acceptance of hosts. Results published by Wilson et al.
(1974) with Campoletes sonorenis (Cameron), a parasitoid of Heliothis virescens (F.) showed that female parasitoids preferred host larvae with a body weight of 43 mgs., in comparison to those weighing 0.4 mgs. and 507 mgs. Also, work conducted with Perilitus coccinellae (Schrank), a parasitoid of adult coccinellids, attacked larger species of coccinellids more often than smaller species
(Richerson and DeLoach 1972).
A. tristis also preferred attacking large hosts weighing 2 8 mgs. in comparison to small hosts weighing 12.9 mgs. Factors responsible for this type of orientation to large hosts are not known at present. However, if the host releases a kairomone, perhaps large hosts release a larger amount than small hosts. A. tristis normally will en
counter hosts weighing 25-2 8 mgs. in the field. Thus, this will help maximize the effectiveness of the parasite.
The rate of parasitization also was influenced by host and parasite density. Parasite efficiency was optimal at a host : parasite ratio of 2:1 with 61% of the larvae 112 successful in host entrance. A host parasite ratio in crease to 3:1 did not enhance larval efficiency. This latter response may be dependent on parasite-host handling time. Each parasite spends a certain amount of time examining a potential host. Thus, over a set period of time a larval parasitoid can only examine a fixed number of hosts, regardless of the host density (Rolling 1959,
Hassell and Rodgers 1972). Also, if the host releases a kairomone, increasing host density may intensify the kairomone's concentration resulting in the disruption of the parasite’s searching behavior.
Increasing parasite density resulted in a severe reduction in A. tristis larval efficiency. Hassell (1971) studying the behavior of Nemeritis canescans (Grav.), as parasitoid of a flour moth (Ephestia cautella) (Walk.), reported that when two searching parasites met, one or both of them left the immediate searching area after the en counter took place. Thus, increasing A. tristis larval density may result in interference between parasites, detracting them from their normal searching behavior.
Results from host location studies revealed that A. tristis larvae did not search at random. Instead, para sites given a choice between 3 depths, preferred para sitizing those located 1” below the surface of the soil.
Perhaps the parasite larvae aggregate at this level due to 113 favorable soil conditions, including temperature and soil moisture gradients which enhance larval survival.
In summary, the efficiency of first instar larvae was influenced by two environmental factors and four host- parasitoid associated factors. SUMMARY AND CONCLUSIONS
Aleochara tristis Gravenhorst, a staphylinid para sitoid of the face fly, was exposed to a variety of factors to determine their effect on female productivity and efficiency of first instar larvae attempting to locate and parasitize hosts.
Under optimal conditions , which included a steady diet of face fly eggs and larvae, an attractive oviposition site and favorable temperatures (25.6-32.2^0.), females oviposited an average of 502 eggs over an oviposition period of 84 days with one female contributing 1,687 eggs.
Female productivity was primarily influenced by tempera ture, the absence or presence of males and availability of food. Females held at temperatures below 21,1°C. seldom oviposited, while those maintained at 25.6°C.-14 hr. photophase and 18.3°C.-10 hr. scotophase and 32.2°C. averaged 60-7 0 eggs per week during their 2 8 day ovi position period.
Egg production in the laboratory also was dependent on the availability of males and food. Females required multiple matings to sustain oviposition. Otherwise, they dispensed with egg production after 4-5 weeks of isolation
114 115 from males. Females also required face fly eggs and larvae in their diet to continue ovipositing on a daily basis.
Females removed from the latter diet responded by dis continuing egg production within 8-11 days. Therefore, egg production was dependent upon a number of biotic and abiotic factors j all of which may fluctuate under field conditions.
Thus, the success of A. tristis in a given locality may be dependent upon the ability of an entomologist to release
A. tristis adults at a time when conditions for survival and colonization are optimal.
Parasitization of face fly pupae by first instar A. tristis larvae was dependent upon environmental and host- parasitoid related factors. In general, larvae were more successful in parasitizing hosts held at 21.1°C. than those held at 25.6-18.3°C. This direct relationship between temperature and parasitization may be dependent on the inverse relationship between larval longevity and in creasing temperature. Thus, larvae exposed to hosts at more moderate temperatures have more time to search for available hosts.
The second environmental factor which affected larval efficiency was soil moisture. Substrates with soil moistures above 20.3% usually immobilized the larvae and they died without locating a host.
Additional laboratory studies showed that the success 116 of first instar larvae was dependent upon host size, host: parasite density and host location. Parasites "preferred" parasitizing large hosts (2 5-2 8 mgs.). However, since most field collected puparia weighed 2 5 mgs., A. tristis making contact with these hosts should successfully gain entrance.
The most favorable hostrparasite density was 2:1, with 61% of the larvae successful in host entrance. In creasing host and parasite density resulted in the reduction of larval efficiency.
Host location also limited the number of pupae parasitized. Larvae were most successful at parasitizing hosts placed 1" below the surface of the substrate. Larvae may have aggregated at this depth due to favorable tempera ture and moisture gradients which enhanced larval survival.
Thus, larvae made more contact with these hosts.
In summary, female productivity, the searching efficiency of larvae and rate of parasitization were affected by a variety of interacting biotic and abiotic factors.
The success of a parasitoid introduction as a part of a biological control program is dependent upon factors influencing the establishment of the field released parasitoid. At present, favorable temperature conditions exist in Ohio for the establishment of A. tristis. However, 117 the following factors may limit its establishment and effectiveness as a parasitoid;
1. Additional time and funds will be needed to mass
rear and release 7-8 day old parasitoids during
' July and August.
2. A. tristis females require multiple matings to
sustain oviposition. Hence, it may be necessary
to release more males than females to prevent
female isolation which would severely limit their
reproductive capacity.
3. Face fly population fluctuations result in
periodic reductions in the food supply of its
parasitoid. A, tristis may not be able to sustain
oviposition at minimal host populations.
Species of Sphaeridium, Hister, Aphodius, and
Aleochara, during food shortages, may revert to
preying on the eggs and larvae of A. tristis.
Thus, interspecific competition may limit survival
and establishment of parasitoid progeny.
5. Increasing soil moisture, concomitant with spring
and summer rains, immobilizes parasitoid larvae,
limiting the number of hosts parasitized.
6. Face fly puparia usually are found 0.3-6.0 m. from
the dung pat. Hence, first instar parasitoid
larvae may expend part or all of their energy
reserves prior to reaching the host. 118
In addition, problems may develop with other predator- parasitoid species which also occupy bovine fecal droppings
Thus, interspecific competition may further reduce the chances of successful parasitoid establishment or mainte nance of field populations of A. tristis, especially when hosts are scarce.
In my opinion, A. tristis will not become an effective biocontrol agent of the face fly. However, in combination with indigenous face fly predators and parasitoids, A. tristis may play a secondary role in face fly population regulation. APPENDIX A
OVIPOSITION STUDIES
119 120
Table 47. Analysis of variance of the effect of parental age, parental weight and male isolation on preoviposition.
Source DF Mean Square F
Total 70 Mean 1 3907.56 964.75 Age Female 1 9.47 2.33 Age Male 1 0.99 1.23 Female Weight 1 0.99 0.23 Male Weight 1 4.43 1.09 Male Death 1 6,63 1.64 Error 64 4.05
Table 48. Analysis of variance of the effect of female isolation on egg production.
Source DF Mean Square F
Total 43 Female 1 5532.80 6.95 Isolation Error 42 795.58 121
Table 49. Analysis of variance of factors effecting the number of eggs recovered.
Source DF Mean Square F
Total 192 Mean 1 11132.52 101.83 Trail 3 88.92 0.79 Feces 3 602.24 5.43 Face Fly Eggs 1 150.00 1.35 Placement 2 153.38 1.38 Feces x Face fly 3 96.04 0.87 Eggs Feces x Placement 6 545.16 4.92 Placement x Face 2 230.32 2.08 , Fly Eggs Feces x Face Fly 6 65.95 0.59 Eggs X Placement Error 165 110.89
Table 50. Analysis of variance of factors effecting the number of eggs concealed.
Source DF Mean Square F
Total 139 Mean 1 2096.28 47.62 Trail 3 92.47 2.10 Feces 3 1766.72 40.13 Face Fly Eggs 1 213.89 4,86 Placement 2 0.03 0.001 Feces x Face Fly 3 108.06 2 .45 Eggs Feces x Placement 3 1.30 0.03 Placement x Face 1 0.50 0.01 Fly Eggs Feces x Face Fly 3 7.06 0.16 Eggs X Placement Error 119 44.02 122
Table 51. Analysis of variance of the effect of female isolation on percent hatch during week one.
Source DF Mean Square
Total 39 Female 1 5871.54 2.58 Isolation Error 38 2200.20
Table 52. Analysis of variance of the effect of female isolation on percent of eggs hatching during week two.
Source DF Mean Square
Total 39 Female 1 20.74 0.08 Isolation Error 38 255.03 123
Table 53. Analysis of variance of the effect of female isolation on percent of eggs hatching during week three.
Source DF Mean Square F
Total 39 Female 1 572 .29 1.45 Isolation Error 38 394.91
Table 54-. Analysis of variance of the effect of female isolation on percent of eggs hatching during week four.
Source DF Mean Square- F
Total 39 Female 1 182.33 0.20 Isolation Error 38 887.14 124
Table 55. Analysis of variance of the effect of female isolation on total number of eggs produced over a 28 day oviposition period.
Source DF Mean Square F
Total 39 Female 1 223,054.22 42.40 Isolation Error 38 5,260.23
Table 56. Analysis of variance of the effect of female isolation on the average number of eggs produced per day per female.
Source DF Mean Square F
Total 39 Female. 1 270.40 38.62 Isolation Error 38 16.50 125
Table 57. Analysis of variance of the effect of female isolation on the percent of days utilized for oviposition.
Source DF Mean Square F
Total 39 Female 1 0.75 24.43 Isolation Error 38 0.03
Table 58. Analysis of variance of the effect of female isolation on the number of days utilized for oviposition.
Source DF Mean Square F
Total 39 Female 1 270.40 38.62 Isolation Error 38 627.00 126
Table 59. Analysis of variance of the effect of female isolation on the first week of oviposition.
Source DF Mean Square
Total 39 Female 1 34.22 0.34 Isolation Error 38 99.47
Table 60. Analysis of variance of the effect of female isolation on the second week of oviposition
Source DF Mean Square'
Total 39 Female 1 11122.22 17.46 Isolation Error 38 636.94 127
Table 61. Analysis of variance of the effect of female isolation on the third week of oviposition.
Source DF Mean Square
Total 39 Female 1 18318.40 22.58 Isolation Error 38 811.37
Table 62. Analysis of variance of the effect of female isolation on the fourth week of oviposition.
Source DF Mean Square"
Total 39 Female 1 56325.02 50.50 Isolation Error 38 111.54 12 8
Table 63. Analysis of variance of the effect of 14 day male réintroduction on total egg production.
Source DF Mean Square
Total 19 Male 1 1187.49 180.94 Réintroduction Error 18 6.56
Table 64. Analysis of variance of the effect of 14 day male réintroduction on daily egg production per female.
Source DF Mean Square
Total 279 Male 1 15,126.30 398.19 Réintroduction Error 278 37.98 129
Table 65. Analysis of variance of the effect of male réintroduction on each successive day of oviposition over a 14 day oviposition period.
Source DF Mean Square
Total 27 Male 1 151,263.00 153.14 Réintroduction Error 26 987.73
Table 66. Analysis of variance of the effect of male réintroduction on the first week of oviposition,
Source DF Mean Square
Total 19 Male 1 50501.25 88.22 Réintroduction Error 18 572.43 130
Table 67. Analysis of variance of the effect of male réintroduction on the second week of oviposition.
Source DF Mean Square
Total 19 Male 1 554H0.U5 192.72 Réintroduction Error 18 287.67
Table 68. Analysis of variance of the effect of male réintroduction on percent of eggs hatching during the first week of oviposition.
Source DF Mean Square
Total 19 Male 1 3393.01 2.90 Réintroduction Error 18 1167.60 131
Table 69. Analysis of variance of the effect of male réintroduction on the percent of eggs hatching during the second week of oviposition.
Source DF Mean Square
Total 19 Male 1 30921.25 34.74 Réintroduction Error 18 890.13
Table 70. Analysis of variance of the effect of temperature on preoviposition.
Source DF Mean Square
Total 102 Temperature 4 11749.26 66.66 Error 98 26.23 132
Table 71. Analysis of variance of the effect of temperature on oviposition over a 28 day oviposition period.
Source DF Mean Square F
Total 100 Temperature 4 377.87 29.23 Error 96 12.95
Table 72. Analysis of variance of the effect of temperature on the number of days utilized for oviposition.
Source DF Mean Square F
Total 6 8 Temperature i+ 525.76 36.68 Error 64 14.33 133
Table 73. Analysis of variance of the effect of temperature on the percent of days used for oviposition.
Source DF Mean Square F
Total 6 5 Temperature 3 0.67 9.00 Error 62 1.55
Table 74. Analysis of variance of the effect of temperature during the first week of oviposition.
Source DF Mean Square F
Total 99 Temperature 4 9869.36 44.29 Error 95 2 22.81 134
Table 75. Analysis of variance of the effect of temperature during the second week of oviposition.
Source DF Mean Square F
Total 99 Temperature 4 28,513.72 22.91 Error 95 1,244.44
Table 76. Analysis of variance of the effect of temperature during the third week of oviposition.
Source DF Mean Square- F
Total 99 Temperature 4 2 6,214.11 18.79 Error 95 1,394.58 135
Table 77, Analysis of variance of the effect of temperature during the fourth week of oviposition.
Source DF Mean Square
Total 99 Temperature 4 23,361.48 18.61 Error 95 1,254.66
Table 78. Analysis of variance of the effect of temperature on percent of eggs hatching during week one.
Source DF Mean Square
Total 41 Temperature 3 211.00 0.65 Error 38 324.03 136
Table 79, Analysis of variance of the effect of temperature on the percent of eggs hatching during week two.
Source DF Mean Square F
Total 70 Temperature 4 152 3.16 15.05 Error 66 101.17
Table 80. Analysis of variance of the effect of temperature on percent of eggs hatching during week three.
Source DF Mean Square F
Total 72 Temperature 4 4730.73 23.69 Error 6 8 199.63 137
Table 81. Analysis of variance of the effect of temperature on percent of eggs hatching during week four.
Source DF Mean Square F
Total 69 Temperature 3 691.72 4.23 Error 66 163.29
Table 82. Analysis of variance of the effect of temperature and transfer on the first week of oviposition.
Source DF Mean Square
Total 48 Mean 1 74734.08 156.00 Temperature 3 8623.64 18 .00 Transfer 1 73790 .08 154.03 Temp. X Transfer 3 8938.30 18.66 Error 40 479.05
Table 83. Analysis of variance of the effect of temperature and transfer on the second week of oviposition.
Source DF Mean Square F
Total 48 Mean 1 154133.33 104.36 Temperature 3 15959.39 10.80 Transfer 1 8164.08 5.53 Temp. X Transfer 3 1339.36 0.91 Error 40 1476.96 138
Table SU. Analysis of variance of the effect of temperature and transfer on egg viability during the first week of oviposition.
Source DF Mean Square F
Total U8 Mean 1 72696.33 340.00 Temperature 3 U991.03 23.34 Transfer 1 57962.99 271.09 Temp. X Transfer 3 9902.14 46.31 Error uo 213.81
Table 85. Analysis of variance of the effect of temperature and transfer on egg viability during the second week of oviposition.
Source DF Mean Square F
Total 48 Mean 1 220133.34 199.70 Temperature 3 14479.63 13.13 Transfer 1 2152.04 1.95 Temp. X Transfer 3 3572.62 3.24 Error 40 1102.33 139
Table 86. Analysis of variance of the effect of diet on oviposition during week three.
Source DF Mean Square F
Total 99 Diet 4 5294.1149 4.88 Error 95 1084.6194
Table 87. Analysis of variance of the effect of diet on oviposition during week four.
Source DF Mean Square F
Total 99 Diet 4 2442.29 1.11 Error 95 2203 .46 mo
Table 88. Analysis of variance of the effect of diet on egg viability during week three.
Source DF Mean Square F
Total 99 Diet 4 1395.64 0.96 Error 95 1447.71
Table 89. Analysis of variance of the effect of diet on egg viability during week four.
Source DF Mean Square F
Total 99 • Diet 4 2322.11 1.96 Error 95 1183.29 141
Table 90. Analysis of variance of the effect of diet- combination on length of preoviposition.
Source DF Mean Square F
Total 99 Diet 4 71.24 4.26 Error 95 16.71
Table 91. Analysis of variance of the effect of diet on the suspension of oviposition.
Source DF Mean Square F
Total 2 6 Diet 4 14.6 8 2.49 Error 22 5.87 142
Table 92. Analysis of variance of the effect of diet and transfer on egg production during week one,
Source DF Mean Square F
Total 60 Mean 1 168752.07 192.59 Diet 4 461.57 0.52 Transfer 1 82139.99 93.74 Diet X Transfer 4 741.33 0.85 Error 50 876.25
Table 93, Analysis of variance of the effect of diet and transfer on egg production during week two.
Source DF Mean Square F
- Total 60 Mean 1 155958.02 141.87 Diet 4 850.10 0.77 Transfer 1 132822.15 120.83 Diet X Transfer 4 695.82 0.63 Error 50 1099.26 143
Table 94, Analysis of variance of the effect of diet and transfer on egg viability during week one.
Source DF Mean Square F
Total 60 Mean 1 479881.37 1001.45 Diet 4 919.75 1.92 Transfer 1 1471.14 3.07 Diet X Transfer 4 679 .68 1.42 Error 50 479.18
Table 95. Analysis of variance of the effect of diet and transfer on egg viability during week two.
Source DF Mean Square F
- Total 60 Mean 1 284088.96 301.94 Diet 4 4299.78 4.57 Transfer 1 36546.14 38.84 Diet X Transfer 4 3921.11 4.17 Error 50 940.88 144
Table 96. Analysis of variance of the effect of diet on the first week of egg production
Source DF Mean Square F
Total 9 Male 1 446899.60 91.26 Presence Error 8 4896.60
Table 97. Analysis of variance of the effect of diet on the second week of egg production.
Source DF Mean Square
Total 9 Male 1 707560.00 116.36 Presence Error 6080.30 APPENDIX B
LONGEVITY
lil5 Table 98. Cumulative percent mortality of 50 pairs of adult A. tristis held at 5 treatment temperatures.
Percent Average Daily Adult Mortality Temperature Mortality Male Mortality Female Mortality (OC.) (Hours) No. Dead Cum. T No. Dead Cum. ?"
15.6 24 48 72 96 120 144 168 5 10.0 192 6 22.0 4 8 216 13 48.0 4 16 240 12 72 .0 13 42.0 264 6 84.0 3 48 .0 288 3 90.0 2 52.0 312 3 96 .0 7 66.0 336 96.0 3 72.0 360 100.0 14 100.0
21.1 24 48 72 96 1 2.0 120 8 18.0 4 8.0 144 9 36.0 1 10.0 168 11 58.0 9 28.0 -P 192 9 76.0 7 42.0 CD Table 98. Continued.
Percent Average Daily Adult Mortality Temperature Mortality Male Mortality' Female Mortality (°C .) (Hours) No. Dead Cum. T No. Dead Cum. ¥
216 3 82.0 12 66.0 240 5 92.0 10 86.0 264 4 100.0 7 100.0
25.6-18.3 24 __ 48 2 4.0 —— 72 23 50.0 16 32.0 96 12 74.0 12 56.0 12 0 7 88.0 9 74.0 144 6 100.0 10 94.0 168 3 100.0
26.7 24 48 — _ 72 10 20.0 3 6.0 96 23 66.0 10 26.0 120 9 84.0 25 76.0 144 8 100.0 11 98.0 168 1 100.0
32.2 24 5 10.0 1 2.0 48 29 68.0 25 52.0 72 16 100.0 24 100 .0 148
Table 99. Analysis of variance of the effect of temperature on male longevity.
Source DF Mean Square F
Total 249 Temperature 4 463.44 239.19 Error 245 1.94
Table 100. Analysis of variance of the effect of temperature on female longevity.
Source DF Mean Square F
Total 249 Temperature 4 715.23 302.39 Error 245 2.36 149
Table 101. Cumulative percent mortality of 10 replicates (10 larvae/rep) of 1st instar A. tristis larvae held at 5 treatment temperatures.
Percent Average Daily Temperature Mortality Larval Mortality (°C.) (Hours) No. Dead Cum. T
15.6 24 5 5.0 48 7 12.0 72 8 20.0 96 13 33.0 120 14 47.0 144 30 77.0 168 13 90.0 216 10 100.0
21.1 24 3 3.0 48 11 14.0 72 22 36.0 96 59 95.0 12 0 5 100.0
25.6-18.3 24 20 20.0 48 76 96.0 72 3 99.0 96 1 100.0
26.7 24 18 18.0 48 82 100.0
32.2 24 100 100.0 150
Table 102. Analysis of variance of the effect of temperature on first instar larval survival,.
Source DF Mean Square F
Total 499
Temperature 4 277.66 291.24
Error 495 0.95 APPENDIX C
CORRELATION STUDIES BETWEEN HOST PUPAL SIZE AND
ADULT PARASITOID WEIGHT AND SEX RATIO
151 152
Table 103. Individual weight and sex of adult A. tristis
Adult Adult No. Weight Sex No, Weight Se:
1 4.22 M 41 4.20 F 2 2.88 F 42 4.33 M 3 3.02 F 43 5. 73 F 4 3.79 F 44 5.20 M 5 3.75 M 45 5 .14 M 6 5.54 M 46 4.71 F 7 2.65 F 47 4.18 F 8 3.25 F 48 4.38 M 9 3,20 M 49 5.32 F 10 6,85 F 50 1.18 F 11 4.95 F 51 1.18 F 12 2.89 F 52 4.36 H 13 3.12 M 53 5.33 M 14 4.70 F 54 3.13 F 15 4.34 F 55 3.68 M 16 4.87 F 56 4.26 F 17 4.22 M 57 4.98 F 18 4.28 M 58 4.98 F 19 4.97 M 59 4.51 F 20 3.77 F 60 6.21 F 21 5.50 M 61 4.44 M 22 5.11 F 62 2.75 F 23 3.28 M 63 6.88 F 24 2.92 F 64 4.11 M 25 5.51 F 65 3.58 F 26 4.12 F 66 r.98 F 27 4.90 M 67 4.08 M 28 3.82 M 68 4.61 M 29 2.81 M 69 3.38 M 30 4.62 M 70 3.98 F 31 4.07 F 71 3.53 M 32 4.45 F 72 4.91 F 33 5.07 F 73 5.13 M 34 3.57 F 74 4.13 F 35 2.64 M 75 5.18 F 36 3.02 M 76 4.68 M 37 4.57 F 77 4.83 M 38 4.04 M 78 3.85 F 39 4.42 F 79 4.33 F 40 4.18 F 80 4.96 M 153
Table 103. Continued.
Adult Adult No. Weight Sex No. Weight Sex
81 3.92 F 125 4.79 F 82 4.94 F 126 4.30 F 83 5.77 F 127 6.19 F 84 4.72 F 128 5.20 M 85 4.07 M 129 4.28 M 86 5.82 F 130 4.89 F 87 4.17 F 131 3.60 M 88 5.01 F 132 5.88 M 89 3.92 M 133 5.61 M 90 4.67 M 134 6.04 M 91 2.93 F 135 5.62 F 92 3.84 M 136 5.08 F 93 3.67 M 137 3.93 M 94 4.18 F 138 5.74 M 95 4.94 M 139 4. 99 M 96 3.96 F 140 5,30 M 97 6.36 F 141 5.04 M 98 5.32 M 142 5.70 M 99 5.32 M 143 4.26 M 100 5.42 M 144 3.88 M 101 3.85 M 145 5.19 F 102 4.04 F 146 4.61 F 103 5.23 M 147 5.81 M 104 4.52 F 148 4.50 F 105 5.59 M 149 5.89 F 106 5.04 F 150 5.43 M 107 5.34 M 151 4.76 M 108 6.09 M 152 5.37 M 109 4.31 F 15 3 4.16 F 110 5.09 F 154 6'. 90 F 111 5.21 F 155 6.13 F 112 5.72 F 156 6.88 F 113 6.04 M 157 4.21 M 114 4.14 F 158 6.21 F 115 5.68 F 159 4.80 M 116 6.11 M 16 0 4.46 M 117 5.74 F 161 5.10 M 118 4.48 M 182 5.20 M 119 5.69 M 16 3 3.50 M 120 5.44 M 164 4.10 F 121 6.59 M 165 4.16 F 122 6. 51 M 166 4. 00 F 123 4.62 M 167 3.41 M 124 4. 80 M 168 4.80 M 154
Table 103. Continued.
Adult Adult No. Weight Sex No. Weight Se:
169 5.25 M 214 2.21 M 170 4.75 M 215 1.66 F 171 4.50 F 216 1.56 F 172 5.73 F 217 1.10 M 173 3.90 M 218 2.08 M 174 4.65 M 219 2.70 M 175 4.62 M 220 2.55 M 176 2.62 M 221 1.40 M 177 4.15 M 222 2.48 M 178 5.07 M 223 1.92 M 179 5.95 M 224 1.65 M 180 5.40 M 225 1.73 F 181 3.48 F 226 1.29 F 182 6.10 M 227 0.50 M 183 5.90 F 228 1.83 M 184 4. 80 M 229 2.03 M 185 4.70 M 230 1.78 F 186 3.61 M 231 2.21 M 187 4.90 M 232 1.68 F 188 5.50 M 233 2.77 F 189 4.31 F 234 1.59 M 190 5.24 M 235 0.66 F 191 6.32 F 236 2.91 M 192 4.82 F 237 2.45 F 193 2.43 F 238 1.84 F 194 2.28 M 239 2.15 F 195 1.29 F 240 1.10 M 196 2.05 F 241 2.05 F 197 1.64 M 242 2.07 M 198 2.93 F 243 2.42 M 199 2.10 M 244 0.47 M 200 2.40 M 245 2.12 F 201 2 .03 M 246 2.16 M 202 1.30 F 247 1.38 F 203 2.67 M 248 1.95 F 204 2.21 M 249 1.74 M 205 2.35 F 250 1.41 M 206 1.73 F 251 1.14 M 207 1.16 M 252 2.07 F 208 0.56 F 253 1.45 F 209 1.27 M 254 1.22 F 210 1.26 M 255 1.47 F 211 1.57 M 256 2.28 F 212 2.19 F 257 4.45 F 213 1.18 M 258 4.18 M 155
Table 103. Continued
Adult Adult N o . Weight Sex No. Weight Sex
259 5.42 M 297 3.90 M 260 4.81 F 298 3.63 F 261 4.63 F 299 3.13 M 262 4.68 F 300 5,16 M 263 3. 78 M 301 4.41 M 264 4.03 F 302 3.91 F 265 4.40 M 303 4.53 F 266 3.94 M 304 2.71 F 267 5.07 F 305 3.05 M 268 4.23 M 306 3.50 M 269 4.03 F 307 4.38 M 270 4.48 M 308 4.54 F 271 4.08 M 309 4.51 F 272 2.87 F 310 3.23 F 273 3.67 F 311 3.18 M 274 4.73 M 312 4.25 F 275 3.85 F 313 3.26 F 276 3.63 F 314 4.63 F 277 3.43 F 315 3.83 F 278 4.85 M 316 3.18 M 279 3.13 M 317 4.83 F 280 4.35 M 318 3.68 F 281 4.32 F 319 3.58 M 282 4.47 M 320 3.85 F 283 4.39 F 321 4.33 M 284 4.97 M 322 4.38 F 285 3.78 F 323 2.93 M 286 3.83 M 324 4.25 M 287 4.23 M 325 2.58 M 288 3, 98 M 326 ■4.23 F 289 4.08 M 327 3.48 M 290 5.00 F 328 3.43 F 291 4.81 M 329 3.21 M 292 4.43 M 330 4.35 F 293 3.19 M 331 4.95 M 294 4.15 F 332 3.37 F 295 4. 30 M 333 3.81 M 296 5.06 F 334 4.78 M 156
Table 104. Analysis of variance of the effect of adult A. tristis weight on sex ratio.
Source DF Mean Square F
Total 333
Adult Weight 1 . 008 0.004
Error 332 .191 157
Table 105. Effect of increasing host pupal size on adult A. tristis size and sex ratio.
Host Pupal Adult No. Size (mg) Weight Sex
1 6.63 1.53 F 2 7.96 2.37 M 3 8.35 1.92 M 4 8.53 1.86 F 5 8.73 1.77 M 6 9.45 1.99 F 7 10.29 2.32 M 8 10.40 3.00 F 9 15.44 2.71 F 10 15.99 3.19 M 11 17 .49 3.52 M 12 18.66 5.08 M 13 18.95 3.55 F 14 19.15 3.97 M 15 19.17 3.30 M 16 20.40 4.82 F 17 20.44 5.11 M 18 20.63 5.07 M 19 21.58 3.82 F 20 21.79 5.13 F 21 21.97 4.31 F 22 22.60 5.52 , M 23 22.55 6.45 F 24 23.01 5.29 M 25 23.80 6.19- M 26 25.01 4.05 M 27 25.70 5.84 F 28 25.79 5.15 M 29 26.29 5.21 M 30 26.96 5.24 M 31 27.29 5.79 F 32 28.09 5.53 F 33 28.12 6.08 F 34 28.27 5.45 F 35 30.17 5.77 M 158
Table 105. Continued
Adult Host Pupal No. Size (mg) Weight Sex
36 30.38 5.50 M 37 31.42 6.22 F 38 32.29 6.08 F 39 32.87 6.32 F 40 35.04 7.05 M 41 35.11 7.10 F 42 38.23 6.85 F 43 39.19 5.99 M 44 43.07 6.00 F
Average : 22.80 4.70
SD ± : 9.10 1.60 159
Table 106. Correlation coefficients of the effect of pupal weight on adult weight and adult sex, and adult weight on adult sex.
Source Values Significant XY Ri R2
Pupal Wt. Pupal Wt. 0.99 0.999 0.01
Pupal Wt. Adult W t . 0.89 0.81 0.01
Pupal Wt. Adult Sex 0,13 0.18
Adult Wt. Adult Wt. 0.99 0,99 0.01
Adult W t . Adult Sex 0.11 0.01
Adult Sex Adult Sex 1.00 1.00 0,01 APPENDIX D
PARASITISM STUDIES
160 Table 107. Larval survival after 60 hrs. exposure, summarized from each of the 3 trials held at 3 treatment temperatures.
Larval Survival Treat. Temp. Host Pupal No. Pupae N o . Larvae N o . (°C. ) Condition Parasitized Recovered No. Alive % Alive
1 21.1 NP-^ 31 34 31 91.2 25.6-18.3 NP 32 48 32 66.7 32.2 NP 30 31 29 93,5
2 21.1 pb/ 18 40 15 37.5 25.6-18.3 P 29 70 31 44.3 32.2 P 16 42 16 38.0
3 21.1 NP 9 11 9 81.8 P 7 15 7 46.7 25.6-18.3 NP 20 21 16 76.2 P 13 31 13 41.9 32.2 NP 16 17 17 100 .0 P 2 4 2 50.0
a/ NP = Exposed host pupae were non-parasitized •
b/ P = Exposed host pupae were parasitized.
CD H 162
Table 108. Analysis of variance of the effect of temperature and host condition on parasitization of face fly pupae by first instar A. tristis larvae.
Source DF Mean Square F
Total 95 Temperature 2 1388.54 4.46 Host Condition 1 4266.66 13.72 Combined HC vs. 1 1204.17 3.87 Separate HC T X HC 2 894.79 2 .88 T X CHC-SHC 2 113.54 0.36 CHC-SHC X HC 1 16.67 0.05 T X HC X CHC-SHC 2 344.79 1.11 Error 84 311.01
Table 109. Analysis of variance of the effect of temperature on rate of parasitization within treatment one.
Source DF Mean Square
Total 23
Temperature 2 12.50 0.09
Error 21 135.11 163
Table 110. Analysis of variance of the effect of temperature on rate of parasitization within treatment two.
Source DF Mean Square F
Total 2 3
Temperature 2 612.50 4.37
Error 21 139.88
Table 111. Analysis of variance of the effect of temperature and host condition on super- parasitization of face fly pupae by first instar A. tristis larvae.
Source DF Mean Square F
Total 95 Temperature 2 528.12 9.67 Host Condition 1 1.04 0.01 Combined HC vs. 1 126.04 2.30 Separate HC T X HC 2 19 .79 0.36 T X CHC-SHC 2 7.29 0.13 CHC-SHC X HC 1 84.37 1.54 T X HC X CHC-SHC 2 40 . 62 0.74 Error 84 54.61 Table 112. Corrected soil moisture weighing based on four-one hundred gram replicates from each of five soil moistures.
48 Hr. Baked Soil Values Soil Moisture Replicate No. Value (grams) Average ± SD
Air Dried 1 3.4 2 3.1 3 3.2 4 3.2 3.2 ± 0.02 9.0% 1 15.5 2 14.9 3 15.5 4 14.6 15.1 i 0.50 20.0% 1 20.6 2 20.3 3 20.2 4 20.1 20.3 t 0.20 31. 0% 1 31.5 2 31.3 3 31.3 4 30.7 31.2 i 0.30 Saturated 1 42.8 2 43.2 3 40.8 4 40.9 41.9 i 1.2
M cn 4T Table 113. Larval survival after 60 hrs. exposure, summarized from each of the 3 treatment trials held at 5 soil moisture levels.
Larval Survival Treat SM-^ Host Pupal N o . Pupae 1>J CJ • J-idJ. V c : No. Condition Parasitized Recovered No. Alive % Alive
One Air Dry NP-'' 31 33 31 93.9 15.1% NP 36 38 35 92.1 20.3% NP 34 35 32 91.4 31.2% NP 14 17 14 82.3 Sat. NP 11 11 11 100. 0
Two Air Dry pÇ/ 5 11 2 18.2 15.1% P 12 36 11 30.5 20.3% P 12 29 11 37.9 31. 2% P 4 13 4 30.8 Sat. P 5 10 6 60.0
Three Air Dry NP 21 23 21 91.3 P 1 2 1 50.0 15.1% NP 22 23 20 86.9 P 1 2 1 50.0 20.3% NP 22 24 19 79.1 P 5 10 3 30.0 31.2% NP 11 17 8 47.1 P 4 8 4 50.0 S at. NP 1 1 1 100.0 P 1 5 4 80.0 = Exposed pupae nonparasitized. 0 5 a/ SM = Soil moisture level, b/ NP cn £/ P = Exposed pupae parasitized. 166
Table 114. Analysis of variance of the effect of soil moisture and host condition on parasitization of face fly pupae by first instar A. tristis larvae.
Source DF Mean Square F
Total 160 Soil Moisture 4 3552.50 18.02 Host Condition 1 29702.50 150.66 Combined HC vs. 1 122.50 0.62 Separate HC SM X HC 4 2308.75 11.71 SM X CHC-SHC 4 297.50 1.51 HC X CHC-SHC 1 1102.50 5.59 SM X CH X CHC-SHC 4 283.75 1.43 Error 140 197.42
Table 115. Analysis of variance of the effect of soil moisture and host condition on superpara- sitization of face fly pupae by first instar A. tristis larvae.
Source DF. Mean Square F
Total 160 Soil Moisture 4 68.12 1.93 Host Condition 1 50.62 1.43 Combined HC vs. 1 5.62 0.16 Separate HC SM X HC 4 75.62 2 .14 SM X CHC-SHC 4 55.62 1.58 HC X CHC-SHC 1 440.62 9.37 SM X HC X CHC-SHC 4 55.62 1.58 Error 140 35.27 Table 116. Weight, length and width of 25 face fly pupae selected for group one.
Face Fly Pupae No. Weight (mg) Length (mm) Width (mm)
1 7 .89 4.32 1.76 2 15 .99 5.12 1.92 3 10.2 3 4.96 1.60 4 15 .64 4.96 1.92 5 17 .94 5.28 2.08 6 10.07 4.64 1.28 7 15.91 4.92 1.92 8 14.30 4.92 1.92 9 14.30 4.92 1.92 10 14.59 4.80 2.08 11 12 .30 4.80 2.08 12 12.65 4.64 1.92 13 18.30 5.60 2.08 14 14. 30 4.92 1.60 15 8.30 4.64 1.60 16 12 .57 4.32 1.92 17 11.2 3 4.92 1.60 18 17.18 4.80 1.92 19 15.51 5.44 0.76 20 15.69 4.92 1.76 21 4.66 4.64 1.44 22 5.53 4.32 1.28 23 11.45 5.28 1.60 24 10.30 4.80 1.76 25 15 .13 5.12 2.08
CT) Table 117. Weight, length and width of 25 face fly pupae selected for group two.
Face Fly Pupae N o . Weight (mg) Length (mm) Width (mm)
1 2 3.14 5.76 2 .56 2 29.75 6.72 2.88 3 23.21 5.92 2.88 4 32 .94 6.72 3.36 5 32.22 6.08 2.88 6 25.96 5.76 2 .56 7 24.71 6.08 2.72 8 32 .56 6.72 3.04 9 34.42 7.04 3.04 10 24.10 6.08 2 .56 11 26.19 6.24 2.56 12 29 .05 6.56 1.88 13 30 .97 6.72 2.88 14 28.92 6.08 2 .72 15 29.30 5.92 2.72 16 36 .30 6.72 3.04 17 20.17 5.60 2 .24 18 31. 30 6.88 2 .88 19 33.30 6.72 2.72 20 26.00 6. 08 2 .40 21 19 .68 5.44 2 .24 22 24. 54 6.08 2.56 23 36.17 7 .04 3.04 24 23.65 6.08 2 .40 25 29.85 6.56 2.56
O) 00 169
Table 118. Analysis of variance of the pupal weight between group one and group two.
Source DF Mean Square F
Total 49
Weight 1 2988.10 166.09
Error 48 17 .99
Table 119. Analysis of variance of the pupal length between group one and group two.
Source DF Mean Square
Total 49
Length 1 25.29 160.26
Error 48 0.15 170
Table 12 0, Analysis of variance of the pupal width between group one and group two.
Source DF Mean Square F
Total 49
Width 1 11.06 167.51
Error 48 0.06
Table 121. Analysis of variance of the effect of host size on parasitization of face fly pupae by first instar A. tristis larvae.
Source DF Mean Square F
Total 39 Replicates 9 468.05 28.97 Host Size 1 5062.50 0.13 Combined HS vs. 1 22.50 Separate HS HS X CHS-SHS 1 1822.50 10.43 Error 27 174.74 171
Table 122. Analysis of variance of the effect of host size on superparasitization of face fly pupae by first instar A. tristis larvae.
Source DF Mean Square F
Total 39 Replicates 9 67.78 Host Size 1 360.00 5.55 Combined HS vs. 1 40.00 0.62 Separate HS HS X CHS-SHS 1 0.0 0.00 Error 27 64.81
Table 123. Analysis of variance of the effect of increasing host density on parasitization of face fly pupae by A. tristis larvae.
Source DF Mean Square F
Total 23
Host Density 2 770.79 ■ 12 .33
Error 21 62.51 172
Table 124. Analysis of variance of the effect of increasing host density on superparasitization of face fly pupae by A. tristis larvae.
Source DF Mean Square
Total 23
Host Density 2 4.38 0.52
Error 21 8.35
Table 125. Analysis of variance of the effect of increasing parasite density on parasitization of face fly pupae by A. tristis larvae.
Source DF Mean Square
Total 23
Parasite Density 2 2816.86 14.97
Error 21 188.09 173
Table 126. Analysis of variance of the effect of increasing parasite density on superpara sitization of face fly pupae by A. tristis larvae,
Source DF Mean Square
Total 23
Parasite Density 2 2343.79 11.89
Error 21 197.00
Table 127. Analysis of variance of the effect of increasing host density on efficiency of first instar A. tristis larvae.
Source DF Mean Square
Total 23
Host Density 2 1162.50 4.41
Error 21 263.09 174
Table 12 8, Analysis of variance of the effect of increasing parasite density on efficiency of first instar A. tristis larvae.
Source DF Mean Square F
Total 2 3
Parasite Density 2 286.96 1.78
Error 21 160.87
Table 129. Analysis of variance of the effect of pupal location on parasitization of face fly pupae by A. tristis larvae.
Source DF Mean Square F
Total 23 Replicate 3 55.36 Soil Depth 2 807.43 9 .63 Combined DS vs 1 26.67 0.32 Separate S.D. SD X CSD-SSD 2 948.15 11.31 Error 15 83.81 175
Table 130. Analysis of variance of the effect of pupal location on superparasitization of face fly pupae by A. tristis larvae.
Source DF Mean Square F
Total 23 Replicate 3 0.91 Soil Depth 2 10.77 12 .74 Combined SD vs. 1 5.51 6.52 Separate SD Error 15 0.84
Table 131. Analysis of variance of the effect of pupal location on rate of parasitization between treatments one, two and three.
Source DF Mean Square F
Total 11
Soil Depth 2 18.54 2 .26
Error 9 8.16 176
Table 132, Analysis of variance of the effect of pupal location on rate of superparasitization between treatments one, two and three.
Source DF Mean Square F
Total 11
Soil Depth 2 0.2 0.4
Error 9 0,5
Table 133. Analysis of variance of the effect of pupal location on rate of parasitization within treatment four.
Source DF Mean Square
Total 11
Soil Depth 2 1722.29 11.85
Error 9 147.80 177
Table 134. Analysis of variance of the effect of pupal location on rate of superparasitization within treatment four.
Source DF Mean Square F
Total 9
Soil Depth 2 17.43 14.37
Error 7 1.21 BIBLIOGRAPHY
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