How and why ectotherm body sizes change with temperature CBD Seminar with Dr Asta Audzijonyte
Many experimental studies show that ectotherms raised at warmer temperature grow faster as juveniles but reach smaller adult body sizes. This “shrinking” of body sizes is considered as a thirduniversal response to global warming, with profound implications for ecosystems and fisheries.
Yet the universality of this response and, most importantly, the mechanisms behind it remain hotly debated.
On one hand “shrinking” of fish in warmer waters is explained through physiological constraints that in one way or another limit adult growth. On the other hand, faster juvenile growth and earlier maturation in warmer temperature may mean that smaller adult body sizes simply make evolutionary sense.
In this talk Dr Asta Audzijonyte will first present a study of over 300 fish species, exploring how mean body sizes change across temperature gradients in space and time. He will show findings from a multi-generation experiment with zebrafish (Danio rerio), demonstrating that smaller adult body sizes are best explained by energy allocation decisions and not metabolic constraints.
Dr Audzijonyte will conclude by discussing the implications of these findings to how we model and forecast climate change responses, emphasising the importance of evolutionary perspective and caveats of extrapolating acute experimental results into long-term predictions.
Dr Asta Audzijonyte is a research fellow at the Institute for Marine and Antarctic Studies, University of Tasmania, Australia. She has an interdisciplinary research background in evolutionary biology, ecological modelling and molecular ecology. Her current research uses macroecological modelling to understand how human induced changes in growth and reproductive schedules of marine organisms (life-histories) and redistributions of species are affecting marine ecosystem function, productivity and resilience.