Social organisation and population genetics of the Threatened great desert skink, Liopholis kintorei Siobhan Dennison BSc (Hons I) Department of Biological Sciences Faculty of Science and Engineering Macquarie University Thesis presented for the degree of Doctor of Philosophy, March 2015 TABLE OF CONTENTS ABSTRACT...............................................................................................i DECLARATION.......................................................................................iii PERSONAL ACKNOWLEDGEMENTS...................................................iv PRESENTATIONS OF RESEARCH FROM THIS THESIS....................vii LIST OF FIGURES.................................................................................viii LIST OF TABLES.....................................................................................x CHAPTER 1: General introduction...........................................................1 Social organisation.........................................................................................2 Social organisation in reptiles.......................................................................3 The Egernia group as a model system..........................................................5 Thesis overview...............................................................................................9 Literature cited...............................................................................................11 CHAPTER 2: Genetic divergence among regions containing the Vulnerable great desert skink (Liopholis kintorei) in the Australian arid zone........................................................................................................19 Abstract..........................................................................................................20 Introduction....................................................................................................21 Methods..........................................................................................................23 Results............................................................................................................28 Discussion.....................................................................................................34 Acknowledgements.......................................................................................38 Literature cited...............................................................................................39 Supplementary material 2.1 – microsatellite development...........................46 Supplementary material 2.2 – genetic divergence plots...............................50 Supplementary material 2.3 – climate data..................................................52 CHAPTER 3: Sex-biased dispersal and fine-scale movement in a group- living lizard, the great desert skink, Liopholis kintorei.............................55 Abstract..........................................................................................................56 Introduction....................................................................................................56 Methods..........................................................................................................63 Results............................................................................................................67 Discussion.....................................................................................................72 Acknowledgements.......................................................................................77 Literature cited...............................................................................................78 Supplementary material 3.1 – additional analyses of movement.................86 ! CHAPTER 4: Variable social organisation in a group-living lizard, Liopholis kintorei.....................................................................................87 Abstract.........................................................................................................88 Introduction...................................................................................................89 Methods.........................................................................................................93 Results...........................................................................................................99 Discussion...................................................................................................109 Acknowledgements....................................................................................118 Literature cited............................................................................................118 Supplementary material 4.1 – growth curve...............................................126 Supplementary material 4.2 – additional analyses of relatedness.............129 CHAPTER 5: Do bigger heads make burly males? Sexual selection and the evolution of sexual head size dimorphism in lizards.......................137 Abstract........................................................................................................138 Introduction..................................................................................................138 Methods........................................................................................................143 Results..........................................................................................................146 Discussion...................................................................................................154 Acknowledgements.....................................................................................159 Literature cited.............................................................................................159 Supplementary material 5.1 – correlation coefficients................................173 CHAPTER 6: General Discussion........................................................175 Overview.......................................................................................................176 Evolutionary implications...........................................................................179 Conservation implications..........................................................................182 Suggestions for future research................................................................184 Conclusion...................................................................................................188 Literature cited.............................................................................................189 APPENDIX: Additional information.......................................................195 ! ! ! Abstract The great desert skink, Liopholis kintorei, is a listed Threatened species with a patchy distribution across the arid zone of central and western Australia. It is a member of a group of Australian lizards, the Egernia group, recently adopted as model species for the early evolution and maintenance of vertebrate sociality. Most Egernia group species that live in stable, kin-based groups utilise pre-existing shelter sites such as rock crevices, but L. kintorei is unique in that individuals cooperatively construct and maintain extensive burrow systems that house kin. I researched aspects of the behavioural ecology and social structure of L. kintorei, using field-based methods and molecular techniques. I captured individuals from a study population at the Australian Wildlife Conservancy’s Newhaven Sanctuary in central Australia, at which a total of seven months of fieldwork was carried out over three years. The results of my research are discussed in the context of the evolution and maintenance of kin-based social living, with comments on the implications for the species’ conservation in central Australia. Social organisation was investigated by trapping lizards at their burrows over the three years and through molecular analyses of relatedness within and among groups. Like other members of the Egernia group, L. kintorei has a complex social structure. Generally, I found that L. kintorei at Newhaven live in groups of related individuals, although there is considerable variation among groups in their size, structure and stability across years: some groups involved male–female pairs together for a single season, while one group contained a mated pair and offspring from three separate seasons. It is possible that L. kintorei social groups are not so constrained by habitat availability because of their ability to construct their own shelter sites. However, the importance of stable food sources in the unpredictable ! i! ! ! desert environment could maintain group living in this species because tolerance among group members would allow them to share such resources rather than compete among kin. Through broader-scale genetic analyses, I found evidence of male-biased dispersal, with no genetic structure among males, but significantly high relatedness among females at short distance classes. This was supported by the recapture data for males, showing a higher level of movement among burrows than for females. Males were captured, on average, at a higher number of distinct burrows than were females, and the distance between capture points was also higher. There was also sexual head-size dimorphism in this species, with males having longer and broader heads than females, relative to body size. This trait may be maintained