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
Sex, parthenogenesis and adaptation: a novel laboratory 'natural selection' experiment testing the adaptive significance of sexual and asexual reproduction. One of the greatest challenges for evolutionary biology is explaining the widespread occurrence of sexual reproduction. Many theoretical models show some inherent benefits of sex, however these models make assumptions that little or no empirical data exists for. Using a novel phenomenon found in the parasitoid wasp genus Trichogramma, I will ....Sex, parthenogenesis and adaptation: a novel laboratory 'natural selection' experiment testing the adaptive significance of sexual and asexual reproduction. One of the greatest challenges for evolutionary biology is explaining the widespread occurrence of sexual reproduction. Many theoretical models show some inherent benefits of sex, however these models make assumptions that little or no empirical data exists for. Using a novel phenomenon found in the parasitoid wasp genus Trichogramma, I will investigate the adaptive significance of sexual and asexual reproduction in a laboratory natural selection experiment and therefore directly test the theory for the evolution and maintenance of sex. This will be the first such test in a higher organism.Read moreRead less
The evolution of parental care in leeches: costs and benefits in a clade of hermaphroditic, invertebrate ectotherms. Parental care is a basic element of reproduction in many species. Nearly everything we know about parental care comes from study of vertebrates, especially birds and mammals. Leech is synonymous with exploitation, but many of these annelid worms are devoted parents. Because they differ dramatically from most vertebrates, leeches present an excellent, but as yet unused, opportunity ....The evolution of parental care in leeches: costs and benefits in a clade of hermaphroditic, invertebrate ectotherms. Parental care is a basic element of reproduction in many species. Nearly everything we know about parental care comes from study of vertebrates, especially birds and mammals. Leech is synonymous with exploitation, but many of these annelid worms are devoted parents. Because they differ dramatically from most vertebrates, leeches present an excellent, but as yet unused, opportunity to test our theories and understanding of the evoluton of parental care. We will examine the evolution of degrees of care and sibling competition in leech families, and use molecular markers to better understand the genetic structure of populations of these invertebrates.Read moreRead less
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
Hybridization, polyploidy and the evolution of parthenogenesis in the Australian desert. This project considers the ecology and evolution of Australian animals that reproduce by parthenogenesis, i.e. without sex. These animals have long fascinated evolutionary biologists for the clues they provide about the role of sex in evolution. The Australian desert is a hot-spot for parthenogenesis, providing a unique opportunity to study the ecological and evolutionary forces favouring the loss of sex. Ou ....Hybridization, polyploidy and the evolution of parthenogenesis in the Australian desert. This project considers the ecology and evolution of Australian animals that reproduce by parthenogenesis, i.e. without sex. These animals have long fascinated evolutionary biologists for the clues they provide about the role of sex in evolution. The Australian desert is a hot-spot for parthenogenesis, providing a unique opportunity to study the ecological and evolutionary forces favouring the loss of sex. Our research will exploit Australian cases of parthenogenesis to understand how genetic changes associated with the transition to parthenogenesis affect ecological success. This will significantly extend our understanding of both the role of sex in evolution, and of the evolutionary history of the Australian arid zone.Read moreRead less
Linkages between productivity and consistent behavioural traits in fish: implications for harvesting, climate impacts, and selective breeding for aquaculture. The extent to which behavior, growth and reproduction are genetically linked in fish populations is unknown, but critical for predicting the impacts of fish harvesting and climate warming, and developing fish stains for aquaculture. If strongly linked, fish harvest will always remove aggressive, large and productive fish, requiring their p ....Linkages between productivity and consistent behavioural traits in fish: implications for harvesting, climate impacts, and selective breeding for aquaculture. The extent to which behavior, growth and reproduction are genetically linked in fish populations is unknown, but critical for predicting the impacts of fish harvesting and climate warming, and developing fish stains for aquaculture. If strongly linked, fish harvest will always remove aggressive, large and productive fish, requiring their protection; in aquaculture, selecting for productive fish will also increase aggression-related injuries. If not strongly linked, we may be able to select for high productivity and low aggression in fish, or high productivity and low metabolism, thus reducing feed costs in aquaculture associated with aggressive behaviour leading to injury and infection, and reduced growth at warmer temperatures.Read moreRead less
Mechanisms of plant species co-existence in species-rich ecosystems: testing hypotheses using spatially-explicit field data and computer models. A generally accepted explanation for the co-existence of species in high diversity communities is one of the outstanding unresolved issues in ecology. Current hypotheses fail to satisfy in their generality; spatial implications are inadequately explored empirically, and the hypotheses are not testable within a common framework. Advances in spatial analy ....Mechanisms of plant species co-existence in species-rich ecosystems: testing hypotheses using spatially-explicit field data and computer models. A generally accepted explanation for the co-existence of species in high diversity communities is one of the outstanding unresolved issues in ecology. Current hypotheses fail to satisfy in their generality; spatial implications are inadequately explored empirically, and the hypotheses are not testable within a common framework. Advances in spatial analysis and complex system modelling now make the search for a general explanation feasible. This project will parameterise and test the different co-existence hypotheses using spatial statistics, empirical/experimental studies of dispersal, recruitment, competition and herbivory, and spatially-explicit computer simulation models of community assemblage in species-rich Australian shrubland communities.Read moreRead less
How does allocation to each sex evolve in hermaphrodites? New insight from the sea. Understanding the ability of hermaphroditic animals to adapt their sex allocation to suit environmental conditions will pave the way for integration between pure and applied research. Such understanding can provide stakeholders across a range of disciplines (natural resource management, aquaculture, conservation) with key information about genetic and environmental influences on the reproduction of many species o ....How does allocation to each sex evolve in hermaphrodites? New insight from the sea. Understanding the ability of hermaphroditic animals to adapt their sex allocation to suit environmental conditions will pave the way for integration between pure and applied research. Such understanding can provide stakeholders across a range of disciplines (natural resource management, aquaculture, conservation) with key information about genetic and environmental influences on the reproduction of many species of significant ecological, economic and social value with this mating system. This research will yield knowledge at the very forefront of evolutionary ecology, enhancing Australia's reputation for research excellence in this field, and further benefit Australian science through the training of young scientists.Read moreRead less