Research project title
How hydric & thermal physiological traits of North Australian dtellas compare across species & environments
Abstract
The physiology of many Australian Gehyra gekkonids (dtellas) are not well understood, partly due to the cryptic nature of several species- many of which have only been recently identified. Measuring physiological traits can reveal whether species have adapted to their environment and can provide insights into their evolutionary history of dispersal and trait development. This approach can also predict how species might respond to future environmental changes and explain the co-existence of sympatric species.
Investigating the physiology of Gehyra species also addresses broader questions about the relationship between physiology and climate in tropical reptiles. It is often assumed that the relatively stable climatic conditions of tropical environments limit the potential for species to specialise their thermal or hydric physiology. However, reptiles from the wet-dry tropics experience significant seasonal differences in climatic humidity despite relatively stable environmental temperatures.
This project investigated evaporative water loss (EWL) rates and preferred temperatures of 18 dtella species from the seasonal tropics of north Australia. These physiological traits were measured in the field and in controlled conditions in a laboratory setting, and were compared across species, season, and climate.
Interspecific differences in EWL were limited, though a strong seasonal effect was present, with all species significantly reducing their EWL rates during the dry season. Thermal preferences showed potential climate associations but generally remained fixed across seasons and acclimation conditions. Dtellas prioritised thermal over hydric regulation in the short-term and did not prefer humid conditions even when thermally neutral.
These findings suggest Gehyra employ different strategies to regulate their physiological states, aligning with tropical Australia’s strong seasonal humidity fluctuations but stable thermal conditions: plasticity in EWL allows dtellas to cope with humidity changes, while behavioural habitat selection reflects use of thermal refugia. These results contribute to a broader understanding of reptile ecophysiology and challenge assumptions about the adaptability of tropical reptiles.
Research interests
Kade’s research interests are centred around reptile ecology, with a particular emphasis on crocodile biology, management, and behaviour. Drawing from their experience in predator ecology, where they investigated the impact of crocodiles on prey dynamics, and their PhD work on the ecophysiology of native Australian geckos, Kade is passionate about understanding the unique adaptations and ecological roles of Australia’s fauna. They have experience in employing a combination of field studies and laboratory experiments to explore these dynamics, aiming to advance current understandings of animal biology and how this relates to the environment, particularly in Australia’s north.