The evolution of energy metabolism in ectotherms. Metabolic rate is the rate at which organisms take up, transform, and expend energy and materials. The primary outcome of this initiative is a comprehensive understanding of the effect of climate on the metabolic rate of ectothermic vertebrates, including goannas, fish and toads. Our research will encompass aquatic and terrestrial environments; temperate and tropical habitats; and include both iconic native species and alien invasive ones. We se ....The evolution of energy metabolism in ectotherms. Metabolic rate is the rate at which organisms take up, transform, and expend energy and materials. The primary outcome of this initiative is a comprehensive understanding of the effect of climate on the metabolic rate of ectothermic vertebrates, including goannas, fish and toads. Our research will encompass aquatic and terrestrial environments; temperate and tropical habitats; and include both iconic native species and alien invasive ones. We seek to understand not only how and why species in these environments vary in their metabolic rate, but also the consequences of this variation. Such knowledge will be important in understanding how climate change does and will affect animals and in predicting its consequences.Read moreRead less
The evolution of periodic ventilation in insects. The primary outcome of this research initiative is a new approach to the understanding of the evolution of periodic ventilation in insects. It involves researchers from four Australian universities, and will showcase the strength of Australian research and the diversity of the Australian insect fauna, and demonstrate the utility of the Australian environment as a model system for the study of fundamental biological problems. The research deals wi ....The evolution of periodic ventilation in insects. The primary outcome of this research initiative is a new approach to the understanding of the evolution of periodic ventilation in insects. It involves researchers from four Australian universities, and will showcase the strength of Australian research and the diversity of the Australian insect fauna, and demonstrate the utility of the Australian environment as a model system for the study of fundamental biological problems. The research deals with the influence of microclimate on the physiology of insects. This will lead to an appreciation of the ability of these species to respond to climate change.Read moreRead less
Does testosterone produce duds or studs? A performance-based examination of the Immunocompetence Handicap Hypothesis. The evolutionary persistence of testosterone (T) as a vertebrate reproductive hormone is viewed as a double-edged sword. On the one hand T secretion is required for development and expression of appropriate reproductive functions. On the other hand T is known to suppress immune functions and is thus considered a liability to male health. We are examining an alternate hypothesis: ....Does testosterone produce duds or studs? A performance-based examination of the Immunocompetence Handicap Hypothesis. The evolutionary persistence of testosterone (T) as a vertebrate reproductive hormone is viewed as a double-edged sword. On the one hand T secretion is required for development and expression of appropriate reproductive functions. On the other hand T is known to suppress immune functions and is thus considered a liability to male health. We are examining an alternate hypothesis: that T-induced immunosuppression benefits breeding males by protecting their physical performance levels during immune challenge. We will examine this hypothesis by quantifying the interactive effects of T and immune challenge on the aerobic capacity of male birds.Read moreRead less
The evolution of dim light vision in vertebrates. High sensitivity (rod-based) vision has been extremely important for the survival and adaptive radiation of many vertebrates, including humans over evolutionary time. This multidisciplinary project will reveal the evolutionary and physiological constraints on early photoreception and the difficulties in operating over an enormous range of lighting conditions. Not only will the findings be crucial for our understanding of basic mechanisms of dim l ....The evolution of dim light vision in vertebrates. High sensitivity (rod-based) vision has been extremely important for the survival and adaptive radiation of many vertebrates, including humans over evolutionary time. This multidisciplinary project will reveal the evolutionary and physiological constraints on early photoreception and the difficulties in operating over an enormous range of lighting conditions. Not only will the findings be crucial for our understanding of basic mechanisms of dim light vision, but also provide potential insights into the physiological bases of various rod dystrophies affecting humans and the improved design of more sensitive cameras and safe light environments for rearing animals in captivity e.g. for aquaculture.Read moreRead less
Testing the adaptive benefit of physiological acclimation. For over a century, physiologists have observed that organisms can modify their physiological function in response to changes in the environment, a process known as acclimation. However, until recently, the adaptive benefit of these acclimation responses has been assumed rather than tested. In this study, I will utilize the effects of temperature on the ability of male mosquito fish (Gambusia holbrooki) to obtain matings and subsequently ....Testing the adaptive benefit of physiological acclimation. For over a century, physiologists have observed that organisms can modify their physiological function in response to changes in the environment, a process known as acclimation. However, until recently, the adaptive benefit of these acclimation responses has been assumed rather than tested. In this study, I will utilize the effects of temperature on the ability of male mosquito fish (Gambusia holbrooki) to obtain matings and subsequently sire offspring to test the benefit of both thermal acclimation and developmental plasticity. This will allow the most comprehensive test of two important hypotheses in comparative physiology: the Beneficial Acclimation Hypothesis and the Beneficial Developmental Plasticity Hypothesis.Read moreRead less
The evolution of colour vision in vertebrates. Colour vision plays a crucial role in the lives of many animals including vertebrates. However, very little is known about the origins of colour vision and we aim to fill this gap. Photoreceptors (cone cells) with sensitivities to different colours mediate colour vision (humans possess blue, green and red cones). This study will examine the structure, physiological responses and molecular biology of these cells in the closest living relatives of the ....The evolution of colour vision in vertebrates. Colour vision plays a crucial role in the lives of many animals including vertebrates. However, very little is known about the origins of colour vision and we aim to fill this gap. Photoreceptors (cone cells) with sensitivities to different colours mediate colour vision (humans possess blue, green and red cones). This study will examine the structure, physiological responses and molecular biology of these cells in the closest living relatives of the early vertebrates. The underlying mechanisms for spectral tuning, the genetic rate of evolutionary change and the importance of colour in visual ecology will also be examined.Read moreRead less
Evolution of viviparity in reptiles: the fundamental role of junctional complexes. This project utilises unique Australian reptile fauna to understand global questions in fundamental biology. We will discover basic biological information on native species, which will be important in future conservation of Australian ecosystems and animals and ultimately in helping to maintain Australia's biodiversity. The project also provides training opportunities for graduate and undergraduate students in ....Evolution of viviparity in reptiles: the fundamental role of junctional complexes. This project utilises unique Australian reptile fauna to understand global questions in fundamental biology. We will discover basic biological information on native species, which will be important in future conservation of Australian ecosystems and animals and ultimately in helping to maintain Australia's biodiversity. The project also provides training opportunities for graduate and undergraduate students in several different research methods that are widely applicable in the more general Australian workforce. Because the research work is genuinely cross-disciplinary research, its findings are applicable to both biological and medically oriented technologies.Read moreRead less
Uterodomes and the evolution of viviparity. We will test the hypothesis that uterodomes, which are cell structures unique to the early pregnant uterus in mammals, and the cellular changes accompanying their development, are essential to the evolution of viviparity in amniotes. The proposal stems from our recent discovery that uterodomes develop in the uteri of viviparous lizards as well as in mammals, suggesting key commonalities at the cellular level in the evolution of live birth across amnio ....Uterodomes and the evolution of viviparity. We will test the hypothesis that uterodomes, which are cell structures unique to the early pregnant uterus in mammals, and the cellular changes accompanying their development, are essential to the evolution of viviparity in amniotes. The proposal stems from our recent discovery that uterodomes develop in the uteri of viviparous lizards as well as in mammals, suggesting key commonalities at the cellular level in the evolution of live birth across amniote vertebrates. We will take advantage of the unique combination of placental types among Australian lizards, including a species with both oviparous and viviparous populations.Read moreRead less
Flexibility in the timing of parturition: the key to viviparity in lizards? Embryos of viviparous lizards usually gain adequate nutrients from yolk. Why then has placentotrophy evolved in some species, and what new opportunities has it opened up? The answer may lie in the advantages gained from flexibility in the timing of birth, made possible by supplementary transfer of storage lipids to embryos during gestation. We argue that this provides a pivotal opportunity for evolutionary divergence: so ....Flexibility in the timing of parturition: the key to viviparity in lizards? Embryos of viviparous lizards usually gain adequate nutrients from yolk. Why then has placentotrophy evolved in some species, and what new opportunities has it opened up? The answer may lie in the advantages gained from flexibility in the timing of birth, made possible by supplementary transfer of storage lipids to embryos during gestation. We argue that this provides a pivotal opportunity for evolutionary divergence: some alpine species exploit flexible parturition; other species replace optional placentotrophy with obligate transfer. Our unique experimental approach, using two well-researched clades of viviparous skinks, will result in new testable hypotheses about the evolution of viviparity.Read moreRead less
How and why do female lizards manipulate the sex and size of their offspring. Mathematical models suggest that reproducing females may be able to enhance their evolutionary fitness by modifying the relative allocation of resources to sons versus daughters. This project uses a model reptile system and an integrated series of experimental and field studies to examine patterns of maternal allocation to sons versus daughters and differential male and female offspring fitness in a range of environmen ....How and why do female lizards manipulate the sex and size of their offspring. Mathematical models suggest that reproducing females may be able to enhance their evolutionary fitness by modifying the relative allocation of resources to sons versus daughters. This project uses a model reptile system and an integrated series of experimental and field studies to examine patterns of maternal allocation to sons versus daughters and differential male and female offspring fitness in a range of environments. This study will provide robust tests of adaptationist hypotheses from sex-allocation theory and provide quantitative data necessary to understand the evolution of sex-determination systems in reptiles.Read moreRead less