Bachelor of Conservation Biology (Honours)
School of Earth, Atmospheric and Life Sciences
Ritchie, Daniel, Geographic variation in thermal physiological traits: the role of thermal stress on telomere length in a polymorphic ectotherm, Bachelor of Conservation Biology (Honours), School of Earth, Atmospheric and Life Sciences, University of Wollongong, 2021.
Geographic variation in thermal adaption is common across ectothermic organisms due to their intrinsic metabolic link with ambient temperatures. However, in the face of altered thermal regimes, ectotherms may incur an array of biomolecular costs associated with suboptimal temperatures. As such, this thesis aimed to investigate the effect of altered thermal regimes on the thermal physiology of two populations of a polymorphic lizard Ctenophorus pictus. Lizards from both a warm adapted and cool adapted population were acclimated in either a warm or cool treatment for three-months, and various metrics of thermal physiology were assessed pre-and post-acclimation. Chapter 2: Populations were found to differ significantly in several traits such as metabolic rate, body size, basking behaviour and reproductive investment, potentially indicating thermal adaption between the populations. Surprisingly, temperature treatment only influenced post-maturity skeletal growth, with individuals in the cool treatment growing considerably longer, suggesting equivalent levels of phenotypic plasticity across both populations. Chapter 3: Telomere length as a potential biomolecular cost of sub-optimal temperatures was quantified via qPCR from blood samples in the field, pre-and post-acclimation. Surprisingly, telomere length was only significantly shorter for the cold-adapted population in the cool room, contrasting with the majority of theoretical predictions. Increased basking activity due to the decreased temperatures may account for such a result; however, no such trend was seen in the warm adapted population. Population-specific telomere response to altered thermal regimes found in this experiment is the first of its kind and represents a tantalizing new ecological research area. Overall, the results of this thesis demonstrate levels of thermal adaptation within both populations of C. pictus as well as levels of thermal plasticity to altered thermal regimes. The potential telomeric cost of thermal acclimation in ectotherms is an underexplored phenomenon, with more research needed to delineate the complex and counterintuitive relationship between temperature and telomere response.
FoR codes (2008)
060806 Animal Physiological Ecology
Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.