The Ecology of the Grape Vine Moth Phalaenoides Glycine Lewin
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WAI'Tþ, INSTITUTE 5 .6 .12 LIBRARY THE ECOI,OGY OF THE GRAPE VTNE MOTH Phalaenoides glycine Lewin. by Charlma L. Cordingley B.Sc.Hons. (f,a Trobe) A ttresis sr:bnitted for the Degree of Doctor of Philosophy in Èhe Faculty of Agricultural Science at the University of Adelaide. Department of EntomologY, V'Iaite Agricultural Research Institute, University of Adelaíde. March L977. l I TABLE OF CONTENTS Page SUM!ÍARY IV DECLARATION vll- AC(NOWIEDGEMENTS viii CHAPTER 1. INTRODUCTION I 1.1 Pest Status I L.2 Phalaenoides glycine - the Insect 2 I.2.L AduIts 4 L.2.2 Eggs 4 r.2.3 Larvae 6 I.2.4 Prepupae 6 L.2.5 Pupae 6 1.3 Topics discussed in this thesis 7 1.3.1 Seasonal history 7 r.3.2 Population numbers I 1.3.3 Distríbution ín the VineYard I L.3.4 oviposition I 1. 3.5 Mortality 9 1.3.6 Native Foodplants t0 r.3.7 Misce Ila¡reous Studies 10 CHAPTER 2. POPULATION STUDIES T2 2.r Seasonal History T2 2.2 Sarq>Iing Area L4 2.3 Sanpling Methods 15 2. 3.1 AduIts 15 2. 3.2 Eggs and Larvae 16 2. 3.3 Pupae L7 2.4 Population Numbers 18 2.4.L Adults 18 2.4.2 Eggs 19 2.4.3 Larvae 20 2.4.4 Pupae 2L 2.4.5 Discussion 22 2.5 Sex Ratio 23 CHAPTER 3. DTSTRTBUfION TN THE VINEYARD 26 3.1 Introduction 26 3.2 The Distributions 26 3.2.1 The Poisson Distribution 27 3.2.2 The Negative Binomial Distribution 27 3.3 Fitting Data to the Poisson Distribution 28 3.4 Fittíng Data to the Negative Binornial DistribuÈion 29 3.5 Measuring the Dispersion 31 3.6 Discussion 32 CITAPTER 4. MATING, REPRODUCTION AND OVIPOSITION 34 4.L Mating behaviour 34 4.2 Pre-oviposition period 35 4.3 Rate of oviposition 35 l- l_ Page 4 .4 The Female Reproductive Tract 36 4 .5 Age and Rep:rcductive State 38 4 .6 Reproductive States in the Fielcl 4L 4.6.1 Live Females 4T 4.6.2 Dead Females 42 4 .7 Fecr.mdity 43 4.7.L Fecundity and Temperature 43 4.7.2 FecundiÈy and Food 44 4.7.3 Fecunôity and Size 44 4.8 Fertility 45 CHAPTER 5. OVIPOSITION SITES AIID FACTORS THAT INFLUENCE THEIR CHOICE 47 5.1 Oviposition Behaviour 47 5.2 Oviposition Sites 48 5.2.L Tn the Field 48 5.2.2 In the Laboratory 50 5.3 Factors Influencing Oviposition 5I 5.3.1 Shelter 51 5.3.2 Wind 53 5.3.3 Food 53 CHAPTER 6. MORTALITY 55 6.1 Predation 55 6. 1.1 Types of Predators 55 6.L.2 Oechal ía schellenberqii - Life HistoTy 56 6.1.3 oechalia schellenbeigii - Seasonal 58 History 6.1 .4 Oechalia schellenbergii - Population 58 Nurnbers 6.I.5 Importance of Predators 59 6-2 Parasitism 61 6.2.L Tachinid F1ies 6t 6.2.2 Hynenopterous Parasites 63 6.2.3 Tmportance of Parasites 65 6.3 Disease 65 6.4 other Causes of MorEality 66 6.4.L Flooding 66 6.4.2 Temperature 67 6.4.3 Rain 68 6.4.4 Mortality of Eggs in the Field 68 6 .4.5 Miscellaneous Causes 69 CHAPTER 7. INSECT - PLANT RELATIONSHIPS 70 7.L Survival of Larvae on Different Foodplants 70 7.2 Rate of Development on Different Foodplants 72 7.3 Oviposition on Different Foodplants 72 7.4 Native Populations 74 CTTAPTER 8. MISCELLAI{EOUS STUDTES 77 I I Prepupal lrtandering 77 8.1.1 Fietd Observations 77 iii. Paqe a.L.2 Attraction to Upstanding Objects 78 8.1.3 Light and TemperaÈure 79 8.1.4 Speed and Distance 80 I .2 Influence of Temperature on Rate of 81 Development I .3 Diapause 84 8.3.1 Induction of Diapause 84 a.3.2 Stage of Induction of Diapause 86 8.3.3 Proportion of the Population 87 Entering Diapause 8. 3.4 Intensity of Diapause 88 8.3.5 Rate of Development of Diapause 89 Larvae CHAPTE R 9. DISCUSSION 90 BTBLIOGRAPHY 103 I 119 2 L2L 3 131 4 r32 l_v. SUMMARY The Grape-Vine Moth, Phalaenoides glycine is a native Australian insect. It originally fed on native foodptants but is now a pest on the introduced grape vine. Adults of the first generation emerged in spring. This generation was completed by OecemUer. The second generation began in mid-January and lasted through untit March. Nunrbers in the second generation were always much higher than in the first generation. ft is suggested that this was due to pupae remaining in diapause from one second generation to the ne:<t. The sex ratio was male dominated at the beginning of the season but changed to female doninated at the end of the season. Overall the sex ratio was 1:1 but it differed both in time and space' The distribution of eggsand larvae ín the vineyard was patchy - at least in the second generation when population nrrmbers were high' In the first generation numbers weïe always low and Èhe distribution did not differ from random. There was usually a pre-oviposition period of I-2 days but this was not necessary for the production of fertile eggs. On emergence no eggs in the ovaries were mature. Maturation continued throughout the life of the rrcth. The rate of oviposition was greatest on the second day of oviposition. The femate reproductive tract and the reproductive states of npths of different ages were exannined and used to determine the mated sÈate of live and dead females in the fie1d. Dead females realized most of their reproductiye potential. The mean fecr:ndity of nrcths was approximately 11OO eggs but rarely hras this nr¡nber laid. The optimum temperature for oviposition \^ras approximately 25oC. Food (adu1t) influenced fecundity V because it influenced longevity. In general heavier moths \¡rere tncre fecr:nd. AIl eggs examined in the field were fertile and all female moths collected had mated. Female npths do not oviposit at rand.om. Most eggs htere fotmd on canes thaÈ trailed on the gror:nd. Shelter was the main factor determiníng choice of oviposition site. Vfind speed affected moth flight and thus, indirectly, oviposition. Moths flew at wind speeds of up to 11.0 km,/hr. The most important predator of Phalaenoides glycine was oechalia schellenbergii. Bug population nunÍbers fluctuated in a sinilar manner to those of larvae but the peaÌ< in bug numbers occurred approximately 3 weeks after the peal< in larval numbers. Other predators included birds, spiders and robberflies. The most important parasites were Tachinid flies. These attacked late instar larvae and in some seasons the rate of parasitism was as high as 64%. Other parasites were a small Eulophid wasp , Euplectrus aqaristae, parasitic on the larval stages of P. glycine; Lissopimpla seÍLipmctata and Ecth:pnpryha intricatoria, two lchneumonids and Eurytoma sp., a Eurytomid, all pupal parasites. Disease (a granulosis virus), flooding of the vineyard in winter, temperature, ploughing and fertility were not considered important causes of death. In the egg stage there was considerable mortality due to failure of the eggs to hatch. Phalaenoides glycine is an r¡nusual insect in that it is a native insect which has seemingly deserted its native hosts and become a pest on the introduced grape vine. B. glycine larvae will survive on Hibbertia scandens (a native of New South hlales) but not on Hibbertia sp. native to South Australia. Adult moths which fed on vines as larvae "preferred" VI vines for oviposit,ion but would oviposi t on Hibbertia if no vines were present. No native populations of P. gLycine have been for:nd in S. Aust. A possible e:çlanation for this is that there are two races of P_. glycine - one which still exists in eastern Australia on its native foodplants and another which became established on grape vines when they were introduced and has since spread to other parts of Australia with the vines. Phalaenoides glycine has 2 generations per season at Langhorne Creek and a partial third generation in Adelaide. This difference in the number of generations per season can be explained by differences in terçerature between the two localities. Prepupae wander for some time before pupating. During this phase they are attracted to upstanding objects of different sizes over different distances. The effect of temperature on wandering prepupae and ttre speed of travel was investigated. Phalaenoides glycine has a facultative diapause in the pupal stage. The intensity of diapause is very variable, some pupae taking little more than 30 days and others well over 100 days to emerge as adults. Diapause is ind.uced in the early larva1 stages (by the 3rd instar). It is induced by low temperatures. Daylength and food by themselves have no effect on induction but they may reinforce the temperature stimulus. var Declaration This thesis contains no material which has been accepted for the award of any other degree or diploma in any university and to tlte best of my knowledge, contains no material previously pr:blished or written by another person, except when due reference is made in the te:ct of the thesis. Ctrarlma L. Cordingley. March L977. 1¡IAI. ACKNOVILED@MENTS I am grateful to my supervisors, Professor T.O. Browning and Dr. R. Laugh]in, for their advice, criticism and encouragement throughout the thesis. I am particularly grateful to Mr. Len Potts for perrnission to rârork on his vineyard at Langhorne Creek and for giving Í€ a 'free hand' to do whatever I war¡ted there.