Evaporative water loss and relative water economy in marsupials. Marsupials are an iconic element of the Australian fauna, so the robust physiological database we will establish has intrinsic educational and scientific value to Australians. We will provide important methodological and analytical advances at the cutting edge of physiological research. This project will sustain our leading role as marsupial physiologists in the international scientific community, contribute to the high-quality tra ....Evaporative water loss and relative water economy in marsupials. Marsupials are an iconic element of the Australian fauna, so the robust physiological database we will establish has intrinsic educational and scientific value to Australians. We will provide important methodological and analytical advances at the cutting edge of physiological research. This project will sustain our leading role as marsupial physiologists in the international scientific community, contribute to the high-quality training of research students, foster national and international collaboration, and generally enhance the scientific profile of Australia. Knowledge of a species' biology and its interactions with the environment are essential for conservation in the face of landscape modification and climate change.Read moreRead less
Calls and constraints: do male frogs signal direct benefits? There is international concern over recent declines and disappearances of many species of amphibians. Australia is a hotspot for declines, but causes of declines remain enigmatic. Approximately one quarter of Australia's 230 amphibian species breed in terrestrial situations, but processes such as salinity, wetland and urban developments and climate change are altering the hydrology of our landscape, and preventing the flood events nece ....Calls and constraints: do male frogs signal direct benefits? There is international concern over recent declines and disappearances of many species of amphibians. Australia is a hotspot for declines, but causes of declines remain enigmatic. Approximately one quarter of Australia's 230 amphibian species breed in terrestrial situations, but processes such as salinity, wetland and urban developments and climate change are altering the hydrology of our landscape, and preventing the flood events necessary for the completion of the lifecycle of many species. This research has important conservation implications because it examines the effects of variable moisture regimes on the physiology and reproductive behaviours of terrestrial breeding frogs.Read moreRead less
Brain temperature regulation in mammals: mechanisms and consequences. Mammals detect increases in body temperature predominantly in the brain. Counterintuitively many mammals selectively cool the brain during heat stress, which appears to defeat the mechanism for inducing cooling responses. We intend to investigate this apparent anomaly which we believe is concerned with optimizing water use in hot conditions. We will further investigate the source of water for evaporative cooling by panting and ....Brain temperature regulation in mammals: mechanisms and consequences. Mammals detect increases in body temperature predominantly in the brain. Counterintuitively many mammals selectively cool the brain during heat stress, which appears to defeat the mechanism for inducing cooling responses. We intend to investigate this apparent anomaly which we believe is concerned with optimizing water use in hot conditions. We will further investigate the source of water for evaporative cooling by panting and discover if there has been convergent evolution in thermoregulatory strategies in the eutherian and marsupial lineages. The data we collect will be used to support a new model for thermoregulation in mammals.
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The comparative physiology of oxygen delivery to the kidney. The kidney is in danger of hyperoxia because the kidney receives so much blood relative to its mass. It is proposed that shunting oxygen between arteries and veins substantially mitigates the risk of hyperoxia, but under certain circumstances shunting substantially increases the risk of kidney hypoxia. Using a combination of synchrotron and histological imaging, This project will carefully define the three-dimensional vasculature of th ....The comparative physiology of oxygen delivery to the kidney. The kidney is in danger of hyperoxia because the kidney receives so much blood relative to its mass. It is proposed that shunting oxygen between arteries and veins substantially mitigates the risk of hyperoxia, but under certain circumstances shunting substantially increases the risk of kidney hypoxia. Using a combination of synchrotron and histological imaging, This project will carefully define the three-dimensional vasculature of the renal cortex in several different species and interpret its functional significance using computational modeling. The outcome of this project will be a new understanding in the comparative physiology of oxygen transport and shunting in the kidney.Read moreRead less
Ecophysiology of water-holding frogs in the Australian arid-zone. Water-holding frogs of arid-zone Australia have an Aboriginal heritage and cultural significance, but many aspects of their natural history, physiology and reproduction are poorly known or documented. We will examine behaviour, physiology, endocrinology, reproductive cycles and movements for these frogs (Cyclorana, Neobatrachus, Notaden, Heleioporus) while active on the surface, and cocoon formation, subterranean movements and dyn ....Ecophysiology of water-holding frogs in the Australian arid-zone. Water-holding frogs of arid-zone Australia have an Aboriginal heritage and cultural significance, but many aspects of their natural history, physiology and reproduction are poorly known or documented. We will examine behaviour, physiology, endocrinology, reproductive cycles and movements for these frogs (Cyclorana, Neobatrachus, Notaden, Heleioporus) while active on the surface, and cocoon formation, subterranean movements and dynamics of water exchange with the soil, metabolic depression, muscle ATP energetics, endocrinology and aspects of reproduction while aestivating underground. We have the expertise and prior experience to accomplish all aspects of the proposed studies.Read moreRead less
Scaling of structure, function and energetics of the vertebrate cardiovascular system. The hearts of mammals, reptiles and fish do different amounts of work, depending on the animal’s metabolic rate and body size. This project attempts to understand why hearts are the size and thickness that they are, and whether this results in minimising the work necessary to satisfy the requirements of the animal.
Sugar and water handling by honeyeaters and sunbirds. Honeyeaters are the major vertebrate pollinators in Australia, playing a vital role in maintenance of healthy ecosystems. These birds are faced with extreme physiological challenges due to their diet, ingesting 2-5 times their body mass in nectar to obtain their daily sugar requirement. Nectarivores are, consequently, masters at processing and assimilating sugars and water; comparative physiology of these charismatic birds will provide deep u ....Sugar and water handling by honeyeaters and sunbirds. Honeyeaters are the major vertebrate pollinators in Australia, playing a vital role in maintenance of healthy ecosystems. These birds are faced with extreme physiological challenges due to their diet, ingesting 2-5 times their body mass in nectar to obtain their daily sugar requirement. Nectarivores are, consequently, masters at processing and assimilating sugars and water; comparative physiology of these charismatic birds will provide deep understanding of sugar and water handling mechanisms. Understanding gut and renal physiology and morphology contributes to the broad base of knowledge required to address pathological and clinical conditions in man, and will enhance our ability to predict effects of environmental change on these birds.Read moreRead less
The entrainment of circadian rhythms in marsupial mammals: behavioural and sub-cellular investigation of non-rod, non-cone ocular photoreceptors. Our investigation will provide a contribution to understanding the role that photoreceptors play in the mechanisms that control circadian rhythms and will ultimately lead to a better understanding of the basic physiology of sleep and circadian cycles, their contribution to learning and memory and their impact on waking performance. Targeted drug develo ....The entrainment of circadian rhythms in marsupial mammals: behavioural and sub-cellular investigation of non-rod, non-cone ocular photoreceptors. Our investigation will provide a contribution to understanding the role that photoreceptors play in the mechanisms that control circadian rhythms and will ultimately lead to a better understanding of the basic physiology of sleep and circadian cycles, their contribution to learning and memory and their impact on waking performance. Targeted drug development and the design of lighting systems effective in regulating circadian rhythms will improve the quality of life and competitiveness of the many citizens who endure abnormal sleep/wakefulness schedules.Read moreRead less
The energetic basis to seed longevity and storage. The energetic basis to seed longevity and storage. This project aims to quantify patterns of metabolic rate in Australian native seeds to research seed ecology, dormancy, germination, longevity and persistence in natural and artificial seed banks. The project aims to optimise and refine current respirometry technology for use with native seeds, understand the allometric relationship and patterns with seed diversity, and apply this knowledge to b ....The energetic basis to seed longevity and storage. The energetic basis to seed longevity and storage. This project aims to quantify patterns of metabolic rate in Australian native seeds to research seed ecology, dormancy, germination, longevity and persistence in natural and artificial seed banks. The project aims to optimise and refine current respirometry technology for use with native seeds, understand the allometric relationship and patterns with seed diversity, and apply this knowledge to benefit restoration and conservation seed banks. By interpreting the energetics of seeds in a phylogenetic context, this project will develop an experimental protocol to predict the physiology and longevity, and test the viability of seeds in storage. Anticipated outcomes are improved efficiency of seed bank storage, conservation and restoration efforts.Read moreRead less
What defines sperm success? The influence of sperm on storage and paternity success in the honeybee Apis mellifera. The honeybee is a species of economic interest and becomes increasingly important for crop pollination, especially in areas where naturally occurring pollinating insects are declining. However, the bee industry struggles to breed sufficient numbers of bees, as climatic changes, parasites and pesticides can kill large numbers of bee hives. Breeding success in honeybees crucially dep ....What defines sperm success? The influence of sperm on storage and paternity success in the honeybee Apis mellifera. The honeybee is a species of economic interest and becomes increasingly important for crop pollination, especially in areas where naturally occurring pollinating insects are declining. However, the bee industry struggles to breed sufficient numbers of bees, as climatic changes, parasites and pesticides can kill large numbers of bee hives. Breeding success in honeybees crucially depends on queens receiving sufficient numbers of viable sperm. The study of honeybee sperm and its possible interactions with the queen can therefore optimize breeding regimes for example by providing ways to estimate male or sperm quality.Read moreRead less