Are natural clones specialists or generalists? Using a model system to test alternative hypotheses for the advantages of parthenogenesis. Parthenogenetic organisms are all-female and reproduce clonally. Through discovering why these unusual organisms are sometimes successful we can better understand the significance of genetic diversity and sex. The Australian arid zone is a ?hot-spot? for parthenogenesis, with at least five independent examples including a native grasshopper and one of its host ....Are natural clones specialists or generalists? Using a model system to test alternative hypotheses for the advantages of parthenogenesis. Parthenogenetic organisms are all-female and reproduce clonally. Through discovering why these unusual organisms are sometimes successful we can better understand the significance of genetic diversity and sex. The Australian arid zone is a ?hot-spot? for parthenogenesis, with at least five independent examples including a native grasshopper and one of its host plants. I will apply modern molecular tools and ecophysiological techniques to test the hypothesis that parthenogenesis is favoured in this grasshopper because it allows the fixation of locally adapted clones. This research will provide a unique insight into the selective forces operating in the arid zone, Australia's largest ecosystem.Read moreRead less
Evolutionary signficance of sexual conflict in orb-web spiders. Multiple mating by females creates intense competition between ejaculates over the fertilisation of her eggs, and has a profound influence on male and female life history and mating strategies. In orb-web spiders, sexual cannibalism creates further conflicts of interest because the male may forfeit future matings. This project examines how life-history and mating strategies interact in these spiders, by identifying the mechanisms t ....Evolutionary signficance of sexual conflict in orb-web spiders. Multiple mating by females creates intense competition between ejaculates over the fertilisation of her eggs, and has a profound influence on male and female life history and mating strategies. In orb-web spiders, sexual cannibalism creates further conflicts of interest because the male may forfeit future matings. This project examines how life-history and mating strategies interact in these spiders, by identifying the mechanisms that determine the outcome of sperm competition; the selection pressures favouring sexual size dimorphism and male size variation; the influence of sexual cannibalism on male mating strategies; and the relationship between female feeding history and her mating behaviour.Read moreRead less
Life history constraints on sexual selection: an investigation using territoriality in butterflies. Contemporary studies into the evolution of male contest behaviour largely ignore the influence of life history. However, contest behaviour should be influenced by life history because the costs of fighting (injury or death) are extracted in a life history currency. Here I aim to measure reproductive value in a territorial butterfly, and to isolate the effects of this parameter, physiological condi ....Life history constraints on sexual selection: an investigation using territoriality in butterflies. Contemporary studies into the evolution of male contest behaviour largely ignore the influence of life history. However, contest behaviour should be influenced by life history because the costs of fighting (injury or death) are extracted in a life history currency. Here I aim to measure reproductive value in a territorial butterfly, and to isolate the effects of this parameter, physiological condition and fighting experience upon male aggression. I propose an innovative experimental approach to unraveling the effects of these covarying life history influences which promises exciting and highly original insights into the evolution of contest behaviour.Read moreRead less
Boom and bust: the role of fire and rain in driving the dynamics of seeds and rodents in arid Australia. The arid Australian environment oscillates between spectacular boom periods, when biotic productivity and diversity are high, and busts, when biotic resources are depleted. This project first outlines a conceptual model of this dynamic and complex system. It then investigates the roles of rainfall and fire in driving boom-bust events, focusing particularly on food resources (seeds) and their ....Boom and bust: the role of fire and rain in driving the dynamics of seeds and rodents in arid Australia. The arid Australian environment oscillates between spectacular boom periods, when biotic productivity and diversity are high, and busts, when biotic resources are depleted. This project first outlines a conceptual model of this dynamic and complex system. It then investigates the roles of rainfall and fire in driving boom-bust events, focusing particularly on food resources (seeds) and their consumers (desert rodents) in the hyper-variable Simpson Desert. We propose observations and experiments to quantify how these climatic events affect seed production, seed fate, and ultimately the dynamics of desert rodents, and outline their importance for effective management of the desert environment.Read moreRead less
The role of plant chemical defences in the population ecology of mammal herbivores. Plants defend themselves against herbivores by producing toxic compounds in their leaves. Many studies show that such compounds influence diet selection by mammal herbivores, but we understand much less about their effects on populations of such species. This project will investigate how concentrations of leaf toxins in eucalypts affect reproductive success, distribution and abundance of the marsupials that feed ....The role of plant chemical defences in the population ecology of mammal herbivores. Plants defend themselves against herbivores by producing toxic compounds in their leaves. Many studies show that such compounds influence diet selection by mammal herbivores, but we understand much less about their effects on populations of such species. This project will investigate how concentrations of leaf toxins in eucalypts affect reproductive success, distribution and abundance of the marsupials that feed on them. The knowledge gained by this study will be important in modelling populations of these marsupial species and predicting their responses to environmental change.Read moreRead less
Can inbreeding avoidance cause the evolution of sex-biased dispersal? This project aims to combine unique long-term data with a novel Citizen Science approach to seek to provide the first complete test of the hypothesis that inbreeding avoidance can cause one of the best known patterns in mammal and bird societies - sex differences in when and how far juveniles disperse. Dispersal is a critically important ecological and evolutionary process, as it influences the fate of populations, and also de ....Can inbreeding avoidance cause the evolution of sex-biased dispersal? This project aims to combine unique long-term data with a novel Citizen Science approach to seek to provide the first complete test of the hypothesis that inbreeding avoidance can cause one of the best known patterns in mammal and bird societies - sex differences in when and how far juveniles disperse. Dispersal is a critically important ecological and evolutionary process, as it influences the fate of populations, and also determines the individuals with which a disperser will spend the remainder of its life. It therefore shapes the likelihood that kin will interact to cooperate or compete, and determines the pool of individuals with which the disperser can mate.Read moreRead less
Facultative sex-determination in a montane lizard. Why is the sex of some reptiles determined by their genetic constitution (sometimes involving heteromorphic sex chromosomes) whereas in other species the animal's sex is determined by the environment (especially, incubation temperature)? Multiple phylogenetic transitions between genetic sex determination (GSD) and environmental sex determination (ESD) suggest that these alternative modes of sex determination possess adaptive significance. Howe ....Facultative sex-determination in a montane lizard. Why is the sex of some reptiles determined by their genetic constitution (sometimes involving heteromorphic sex chromosomes) whereas in other species the animal's sex is determined by the environment (especially, incubation temperature)? Multiple phylogenetic transitions between genetic sex determination (GSD) and environmental sex determination (ESD) suggest that these alternative modes of sex determination possess adaptive significance. However, the selective forces favouring one versus the other remain obscure, despite sustained research in this field by many workers. The recent discovery of BOTH sex-determining systems simultaneously within a single population of alpine lizards provides a unique opportunity to test among competing hypotheses for the evolution of sex-determining systems. I propose an integrated study, in both the field and the laboratory, to clarify the mechanisms and the selective forces involved in the evolution of sex-determination.Read moreRead less
Evolutionary ecology of snakes and lizards. Although reptiles provide excellent "model systems" with which to examine evolutionary and ecological processes, most research in this field has been dominated by studies on other kinds of organisms. I propose a broad-ranging series of studies that will use a diverse array of lizard and snake species to erect and test novel hypotheses on the evolution of phenomena such as mating systems, sexual dimorphism, foraging biology, and reproductive investment ....Evolutionary ecology of snakes and lizards. Although reptiles provide excellent "model systems" with which to examine evolutionary and ecological processes, most research in this field has been dominated by studies on other kinds of organisms. I propose a broad-ranging series of studies that will use a diverse array of lizard and snake species to erect and test novel hypotheses on the evolution of phenomena such as mating systems, sexual dimorphism, foraging biology, and reproductive investment. My experimental studies will clarify the evolutionary role of phenotypic plasticity (that is, direct environmental effects) as well as genetic factors.Read moreRead less
Does adaptive plasticity play a significant role in the initial colonisation of novel habitats? An increased understanding of the evolutionary and ecological processes responsible for generating Australian biodiversity can facilitate effective management and conservation of this unique resource. Islands are especially significant in this context because they host many kinds of distinctive fauna and flora that have vanished from mainland habitats. It is therefore crucial to understand the biolo ....Does adaptive plasticity play a significant role in the initial colonisation of novel habitats? An increased understanding of the evolutionary and ecological processes responsible for generating Australian biodiversity can facilitate effective management and conservation of this unique resource. Islands are especially significant in this context because they host many kinds of distinctive fauna and flora that have vanished from mainland habitats. It is therefore crucial to understand the biology of these small isolated systems, as a way to preserve those unique systems as well as the distinctive evolutionary processes that occur within them.Read moreRead less
Ecology and phylogeography of bird migration between Australia and New Guinea: paradise kingfishers as a model species. This project examines the evolutionary causes and ecological consequences of intra-tropical bird migration between north Australia and New Guinea, one of the major migration systems of the southern hemisphere. I will use the buff-breasted paradise kingfisher as a model species, exploiting two features of its biology (an aerodynamically costly tail and a breeding distribution wi ....Ecology and phylogeography of bird migration between Australia and New Guinea: paradise kingfishers as a model species. This project examines the evolutionary causes and ecological consequences of intra-tropical bird migration between north Australia and New Guinea, one of the major migration systems of the southern hemisphere. I will use the buff-breasted paradise kingfisher as a model species, exploiting two features of its biology (an aerodynamically costly tail and a breeding distribution with a large latitudinal range) to shed light on the costs, benefits, and ecological correlates of intra-tropical migration. Molecular markers will be used to identify non-breeding distributions, migratory patterns, and the biogeographic histories of the different breeding populations within Australia.Read moreRead less