University of Massachusetts Amherst ScholarWorks@UMass Amherst Doctoral Dissertations 1896 - February 2014 1-1-1985 Oviposition-deterring pheromone of Rhagoletis pomonella : release, residual activity, and protection of larval resources from overcrowding. Anne L. Averill University of Massachusetts Amherst Follow this and additional works at: https://scholarworks.umass.edu/dissertations_1 Recommended Citation Averill, Anne L., "Oviposition-deterring pheromone of Rhagoletis pomonella : release, residual activity, and protection of larval resources from overcrowding." (1985). Doctoral Dissertations 1896 - February 2014. 5628. https://scholarworks.umass.edu/dissertations_1/5628 This Open Access Dissertation is brought to you for free and open access by ScholarWorks@UMass Amherst. It has been accepted for inclusion in Doctoral Dissertations 1896 - February 2014 by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact [email protected]. OVIPOSITION-DETERRING PHEROMONE OF RHAGOLETIS POMONELLA RELEASE, RESIDUAL ACTIVITY, AND PROTECTION OF LARVAL RESOURCES FROM OVERCROWDING A Dissertation Presented By Anne Louise Averill Submitted to the Graduate School of the University of Massachusetts in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY May 1985 Entomology OVIPOSITION-DETERRING PHEROMONE OF RHAGOLETIS POMONELLA: RELEASE, RESIDUAL ACTIVITY AND PROTECTION OF LARVAL RESOURCES FROM OVERCROWDING A Dissertation Presented By Anne Louise Averill Approved as to style and content by: Ronald J. Prokopy, Chairman of Committee Ring 1\ Carde, Department Head Entomology ACKNOWLEDGEMENTS I would like to thank: Ron Prokopy for absolutely everything; Joe Elkinton for enthusiasm and encouragement; Craig Edwards for making considerable improvements in the write-up of this work; Sandy Liebhold for the mechanical write-up of this work; Arthur Tuttle for being Arthur in last-chance gulch; John Clark and the goon squad for making several experiments possible; Juliet Tang and Marty Averill for insights and energy that greatly enhanced the breadth of these studies; Hedera Hoover and Ginni Ursin for fine technical assistance; Reg Coler for my pull-up and Don Eaton and Steve Woods for an improved 8AM and 4pm outlook, respectively; Gaylen Jones for solving a wide range of problems; and finally, Ernie Johnson for instilling confidence when it was most needed. I am particularly indebted to my big family, my extended little family (including Dennis LaPointe and Ned Walker) and Ron Prokopy for continuous support and affection. • • • 111 ABSTRACT OVIPOSITION-DETERRING PHEROMONE OF RHAGOLETIS POMONELLA: RELEASE, RESIDUAL ACTIVITY, AND PROTECTION OF LARVAL RESOURCES FROM OVERCROWDING (May, 1985) Anne Louise Averill, B.A., Smith College, 1976 Ph.D., University of Massachusetts Directed by: Ronald J. Prokopy Uniform spacing of eggs by ovipositing females may be adaptively advantageous in any insect species whose larvae develop at constricted sites and who have limited ability to exploit alternative sites. The apple maggot fly, Rhagoletis pomonella (Tephritidae), marks its egg-laying site with a pheromone that elicits dispersal of arriving conspecifics away from already occupied larval resources. This dissertation explores aspects of the oviposition-deterring pheromone (ODP) system of the apple maggot fly. iv I evaluated the effect of fly or fruit treatments on quality and/or quantity of ODP released and found that fly age, fly size, and starvation influenced ODP deposition, whereas fly experience, fly diet, and presence of ODP on a fruit did not (Chapter II). Studies of the residual activity of ODP (Chapter III) revealed that under dry conditions, the pheromone was deterrent for at least 3 weeks. A decline in pheromone activity resulted from exposure to both natural and simulated rainfall. I began evaluation of the role of ODP as a mediator of oviposition site partitioning and as a regulator of larval competition (Chapter IV) by first establishing that the carrying capacity of Crataegus mol1is hawthorns (a native host species of the apple maggot) was 1 larva/fruit. A significant decrease in larval survivorship and components of adult fitness resulted when >1 larva developed in a fruit. The amount of fruit surface marked by a female following oviposition correlated with the carrying capacity of this small host. Further, I found that ODP may need only give the first larva a headstart: in most instances, when 2 days separated introduction of 2 larvae into unpicked hawthorns capable of supporting only a single larva to pupation, the first introduced larva "won;" the second larva introduced v failed to complete development. Finally, sampling throughout the 1.5 month hawthorn ripening season revealed an even dispersion of eggs among fruit following fruit ripening (Chapter V). It appears that ODP could be a principal mediator of this observed egg dispersion pattern in nature. vi TABLE OF CONTENTS • • • ACKNOWLEDGEMENTS.1 *1 ABSTRACT.lv Chapter I. INTRODUCTION .1 II FACTORS INFLUENCING RELEASE OF OVIPOSITION- DETERRING PHEROMONE BY RHAGOLETIS PQMQNELLA FLIES. 6 Introduction .6 Materials and Methods.9 Results and Discussion Variability in trail substance deposition within and among flies . 16 Variability in trail deposition over time Successive fruit marked over a day .17 Successive fruit marked over a week.21 Fly age .21 Starvation .26 Fly size .30 Fly diet .32 Fruit size .35 Pheromone-marked and unmarked fruit.37 Summary.39 III. RESIDUAL ACTIVITY OF OVIPOSITION-DETERRING PHER0M0NA IN RHAGOLETIS PQMQNELLA AND FEMALE RESPONSE TO INFESTED FRUIT.41 Introduction . 41 Materials and Methods . 43 Oviposition-deterring pheromone residual activity over time under dry conditions.44 Effect of rainfall on oviposition- deterring pheromone activity.46 Effect of simulated rain on oviposition- deterring pheromone activity.47 Effect of the presence of a developing larva on fruit acceptance by ovipositing females.48 Results.49 Discussion.57 • • Vll IV. PHEROMONAL MEDIATION OF COMPETITION IN RHAGOLETIS POMONELLA.65 Introduction.65 Materials and Methods.66 Results and Discussion.72 Larval Competition Survivorship.72 Effect of initial egg density on pupal weight.80 Carrying capacity of fruit.83 Adult fitness.85 Oviposition-deterring pheromone as a mediator of larval competition Correlation of amount of pheromone with larval resource requirements.92 Importance of a developmental headstart for a larva.102 Mechanisms of competition among larvae....107 Process of resource exploitation.Ill Evolution of host discrimination.112 V. DISTRIBUTION PATTERNS OF RHAGOLETIS POMONELLA EGGS IN HAWTHORN (CRATAEGUS). 115 Introduction.115 Materials and Methods.118 Results.120 Discussion Dispersion of eggs among fruit.128 Distribution of eggs within and between trees.141 REFERENCES CITED.144 • • • vm LIST OF FIGURES 1. An oviposition-deterring pheromone trail deposited on a Crataegus hawthorn by a R. pomonel l$q\ female. The trail has been dusted with Olivetti^ dry magnetic toner (- xerox powder) 2. The residual activity over time of R. pomonella ODP under dry conditions . 3. The residual activity of R. pomonella ODP exposed to various durations and intensities of natural rainfall . 4. The residual activity of R_. pomonella ODP exposed to various durations of a light or heavy simulated rainfall . 5. Effect of initial R. pomonella egg density on larval survivorship to puparial formation in C. mollis fruit . 6. Percentage of field collected C. mollis hawthorn fruit supporting 0, 1, 2, or 3 R. pomonella larvae to puparial formation . 7. Effect of R. pomonella pupal weight on number of days to first oviposition.87 8. Effect of R. pomonella pupal weight on average lifetime oviposition rate . 89 9. Field bioassay of R. pomonella acceptance of C. mollis fruit marked with different numbers of dragging bouts.94 10. Laboratory bioassay of R. pomonella acceptance of C. mollis fruit marked with different numbers of dragging bouts . 96 11. Effect of 2-day headstart in determining the "winning" R. pomonella larva’s identity for double infestations of C. oxyacantha fruit . 104 12. R. pomonella egg dispersion pattern among C. mollis fruit during August and September, 1982. .122 ix 13. Seasonal changes in percentage of sampled C. mo 11 is fruit infested with R. pomonella eggs, and percentage of observed oviposition punctures that contained eggs . 125 14. Total number of R. pomonella eggs counted for each C. mollis tree subsection . 130 x LIST OF TABLES 1. Time spent during pheromone deposition and length and area of oviposition-deterring pheromone substance deposited by two R. pomonella females offered 12 successive C. oxyacantha fruit on the same day . 18 2. Mean time spent during pheromone deposition and length and area of oviposition deterring pheromone substance deposited by each of 12 R. pomonella females offered 12 successive C. oxyacantha fruit on the same day . 19 Mean time spent during pheromone deposition and mean length and area of oviposition-deterring pheromone deposited by 12 R. pomonella females offered 12 successive C. oxyacantha fruit on the same day . 20 4. Daily mean number of fruit accepted for oviposition, time spent during pheromone deposition, and mean length and area of oviposition-deterring pheromone substance deposited y 11 R^ pomone11a females offered 12 successive —• oxyacantha fruit on each of 7 consecutive days 22 5. Mean time spent during pheromone deposition and mean length and area of oviposition-deterring Pheromone