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The behaviour of the Queensland fruit fly, Bactrocera tryoni (Diptera: Tephritidae), and its implications for improving integrated pest management using the sterile insect technique

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posted on 2022-07-29, 00:47 authored by Jess R Inskeep

Queensland fruit flies, Bactrocera tryoni Froggatt (Diptera: Tephritidae), are one of the most important pests of Australian horticulture due to the severity with which they limit domestic and international trade of host produce. The sterile insect technique (SIT) is used to extirpate or prevent the establishment of wild populations of B. tryoni in some regions, whereby millions of flies are reared, sterilised, and released into agricultural areas. Sterile males are expected to mate with wild females, resulting in infertility of wild females and a generational decline in the wild population. However, sterile B. tryoni often display poor quality arising from adaption to laboratory conditions and exposure to irradiation. These deficiencies can be identified and ameliorated through behavioural studies, which this thesis considered. In the studies described herein, I compared the behaviours of mass-reared (fertile and/or sterile) and wild B. tryoni. Furthermore, I investigated behaviours that likely take place in natural habitats. I investigated the microhabitat distribution of B. tryoni males and females from mass-reared (fertile and sterile) and wild populations in tree canopies through the day. Flies moved systematically through the tree canopy in response to shifting abiotic conditions (temperature, light intensity, and humidity). Next, I observed the spatial and temporal distribution of male mating behaviours (wild, and fertile and sterile mass-reared) at dusk in tree canopies. Mass-reared (both fertile and sterile) males exhibited mating behaviours that differed spatially and temporally from wild conspecifics, which likely attributed to a high tendency for assortative mating. In a laboratory study of the effect of sterilisation on the ability of B. tryoni to tolerate desiccation stress, sterilisation lowered its activity and survival under desiccation stress. Finally, in a study of male-male aggression, I documented the aggressive behaviours of B. tryoni males for the first time. Crowding reduced aggression and mass-reared adults engaged in aggression at a relatively close distance, both of which may negatively affect their ability to compete for resources or repel predators in nature. Through the studies described in this thesis, I highlight areas of improvement for the management of B. tryoni using SIT.


Table of Contents

Chapter one: Introduction -- Chapter two: Canopy distribution and microclimate preferences of sterile and wild Queensland fruit flies -- Chapter three: Spatio-temporal distribution of calling males from sterile and wild populations of the Queensland fruit fly -- Chapter four: Irradiation and hydric stress affect the survival and activity of Queensland fruit flies -- Chapter five: Effect of prior conspecific interactions and age on the aggressive behavior of mass-reared and wild Queensland fruit flies -- Chapter six: Aggression in the Queensland fruit fly: effects of domestication and residency -- Chapter seven: Discussion


This thesis is presented for the requirements for the degree of Doctor of Philosophy Includes bibliographical references (pages 23-42, 63-73, 109-119, 144-158, 180-185, 200-203, 214-219)

Awarding Institution

Macquarie University

Degree Type

Thesis PhD


Thesis (PhD), Macquarie University, Department of Molecular Sciences, 2019

Department, Centre or School

Department of Biological Sciences

Year of Award


Principal Supervisor

Phillip Taylor

Additional Supervisor 1

Polychronis Rempoulakis

Additional Supervisor 2

Bishwo Mainali


Copyright disclaimer: Copyright Jess R. Inskeep 2019.




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