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Y E a R ^ O O ^ Name of Author J ( K I—F\ ^ REFERENCE ONLY UNIVERSITY OF LONDON THESIS Degree P I 'n O Y e a r ^ o o ^ Name of Author j ( K i—f\ ^ COPYRIGHT To. This is a thesis accepted for a Higher Degree of the University of London. It is an unpublished typescript and the copyright is held by the author. All persons consulting this thesis must read and abide by the Copyright Declaration below. COPYRIGHT DECLARATION I recognise that the copyright of the above-described thesis rests with the author and that no quotation from it or information derived from it may be published without the prior written consent of the author. LOANS Theses may not be lent to individuals, but the Senate House Library may lend a copy to approved libraries within the United Kingdom, for consultation solely on the premises of those libraries. Application should be made to: Inter-Library Loans, Senate House Library, Senate House, Malet Street, London WC1E 7HU. REPRODUCTION University of London theses may not be reproduced without explicit written permission from the Senate House Library. Enquiries should be addressed to the Theses Section of the Library. Regulations concerning reproduction vary according to the date of acceptance of the thesis and are listed below as guidelines. A. Before 1962. Permission granted only upon the prior written consent of the author. (The Senate House Library will provide addresses where possible). B. 1962-1974. In many cases the author has agreed to permit copying upon completion of a Copyright Declaration. C. 1975-1988. Most theses may be copied upon completion of a Copyright Declaration. D. 1989 onwards. Most theses may be copied. This thesis comes within category D. This copy has been deposited in the Library of L o ^ This copy has been deposited in the Senate House Library, Senate House, Malet Street, London WC1E 7HU. o d H ; ' S.SOtts CO Mechanisms underlying sexual selection and sexual conflict in Drosophila melanogaster Thesis submitted for PhD by Jon Linklater University College London UMI Number: U592996 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. Dissertation Publishing UMI U592996 Published by ProQuest LLC 2013. Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 “Love is the answer, but while you are waiting for the answer, sex raises some pretty’ good questions.” Woody Allen 2 For Mama and Papa Abstract The revelation that females of many taxa mate with multiple males has broadened perspectives in sexual selection to encompass the study of conflicts of interest between males and females over mating and reproduction. Conflict often exists between the sexes over reproductive decisions such as how often to mate, because the optimum mating rate may often be higher for males than for females. Selection is expected to favour traits in males that manipulate female mating frequency and that confer an advantage over competing males, particularly in relation to post- copulatory competition. A significant fraction of male post-copulatory success in Drosophila melanogaster is determined by the action of accessory gland proteins (Acps) that are transferred by males to females during mating. Acps have significant effects on female behaviour and physiology and have been shown to play a role in mediating sexual conflict. Exploring the role of the male accessory glands and of Acps in moulding evolutionary interactions between the sexes and in determining overall fitness remains an important task and one that will illuminate the mechanisms underlying sexual selection and sexual conflict. In this thesis I use Drosophila melanogaster as a model system to ask how reproductive traits, strategies and morphologies have been shaped by sexual selection and sexual conflict. I show that traits related to ejaculate investment and depletion have evolved in lines of D. melanogaster with an evolutionary history of exposure to high or low levels of sperm competition and mating opportunities. I then describe how I initiated, propagated and analysed lines selected for increased and decreased male accessory gland size. I describe the direct and correlated responses to selection and show that accessory gland size is associated with male post- copulatory success but not with the magnitude of female mating costs. I further probe the nature of female mating costs by analysing the contribution to them of a single Acp, Acp62F. Finally, I summarise my thesis and discuss future directions for investigating the mechanisms of sexual selection and sexual conflict in Drosophila. 4 Table of Contents A bstract .......................................................................................................................................4 List of Figures ......................................................................................................................... 10 List of Tables ............................................................................................................................13 Declaration ............................................................................................................................... 16 Acknowledgements ................................................................................................................. 16 Chapter 1. General Introduction .......................................................................................... 18 1.1 Sexual selection ........................................................................................................... 18 1.2 The evolution of polyandry ...................................................................................... 20 1.3 Evolutionary consequences of polyandry: how males adapt to female promiscuity ....................................................................................................................21 Adaptations of sperm and of ejaculate size in response to sperm competition (Chapter 3) ......................................................................................................................22 Adaptations in male genitalia in response to sperm competition. ........................ 26 Behavioural adaptations in response to sperm competition ................................. 26 Remote mate guarding in response to sperm competition .....................................27 Conflict between the sexes ..........................................................................................27 1.4 Evidence of sexual conflict ....................................................................................... 29 1.5 The mating system of Drosophila melanogaster ...................................................30 1.5.1 Sperm competition in Drosophila melanogaster .......................................31 1.5.2 Accessory gland proteins (Acps) o f Drosophila melanogaster ............... 31 1.5.3 Role o f A cps in Drosophila melanogaster ..................................................32 Decline in female attractiveness, receptivity to mating and increase in egg la y in g ..............................................................................................................................32 Sperm storage and displacement .................................................................................33 Immunological properties of seminal fluid ..............................................................34 1.5.4 Acps, the cost o f mating and sexual conflict .............................................. 34 Acp62F and the cost of mating in Drosophila melanozaster (Chapter 6) .......... 35 1.6 Outline of Thesis .......................................................................................................... 37 Chapter 2 General Materials and Methods ....................................................................... 39 2.1 Fly Culturing ................................................................................................................. 39 2.1.1 Bottles and vials (stocks and experiments).................................................39 2.1.2 Standard larval density culture.................................................................... 39 2.2 M edia.............................................................................................................................. 40 2.2.1 Sugar- Yeast medium ........................................................................................40 2.2.2 Maize- Yeast medium........................................................................................ 40 2.2.3 Grape juice medium ........................................................................................ 40 2.3 Stocks ..............................................................................................................................41 2.3.1 Wild-type Drosophila melanogaster .............................................................41 2.3.2 Manipulating sperm competition by experimental evolution o f sex ratio (Chapter 3 ) ..................................................................................................................... 41 2.3.3 sparkling poliert stock
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