The thermal ecology and physiology of reptiles and amphibians: A user's guide

Abstract

Research on the thermal ecology and physiology of free‐living organisms is accelerating as scientists and managers recognize the urgency of the global biodiversity crisis brought on by climate change. As ectotherms, temperature fundamentally affects most aspects of the lives of amphibians and reptiles, making them excellent models for studying how animals are impacted by changing temperatures. As research on this group of organisms accelerates, it is essential to maintain consistent and optimal methodology so that results can be compared across groups and over time. This review addresses the utility of reptiles and amphibians as model organisms for thermal studies by reviewing the best practices for research on their thermal ecology and physiology, and by highlighting key studies that have advanced the field with new and improved methods. We end by presenting several areas where reptiles and amphibians show great promise for further advancing our understanding of how temperature relations between organisms and their environments are impacted by global climate change.

Glucocorticoids, energy metabolites, and immunity vary across allostatic states for plateau side‐blotched lizards (Uta stansburiana uniformis) residing in a heterogeneous thermal environment

“…In doing so, we revealed CORT was thermally sensitive while BKA corresponded with circulating CORT and glucose across allostatic states. Temperature thus seems to be a principal component directly and indirectly influencing multiple physiological functions, invoking a preeminent concern in ecology for reptiles (Angilletta, 2009; Taylor et al, 2020). Further assessing physiological performance in the context of the thermal environment will be key to forecasting the impacts of climate change on the prospects of survival for reptiles.…”

“…Achieving thermal optima is assumedly difficult as a result (Dawson, 1975; Spotila & Standora, 1985; Stevenson, 1985); presenting variable allostatic outcomes for self‐maintenance (Shine, 2005). However, the extent to which physiological parameters linked to allostatic state vary with T body remains to be fully examined (Taylor et al, 2020), especially in natural settings.…”

Thermal adaptation revisited: How conserved are thermal traits of reptiles and amphibians?

“…Work to date has found little support for narrow‐sense heritability of thermal traits or genetic covariance of thermal traits in reptiles and amphibians, but this is potentially due to limited sample sizes in published studies and the small number of controlled breeding studies. Even so, thermal traits may share pathways and perhaps genetic underpinnings with life‐history traits such as growth (Bronikowski, 2000; Refsnider et al, 2019; Sinervo, 1990; Taylor et al, 2020). A variety of factors can lead to phenotypic covariance of thermal or life‐history traits within individuals, but determining the adaptive significance of such constraints is challenging (reviewed in Bennett, 1997).…”

“…In two panels (D and G), CT max , CT min , and T opt are identical despite divergence in TPC shape. Ideally, performance should be measured at five or more points to characterize differences in TPCs (see Taylor et al, 2020).…”

Competing native and invasive Anolis lizards exhibit thermal preference plasticity in opposite directions

“…For example, rates of signal production in organisms from insects to frogs change with habitat temperature (Gerhardt, 1978; Martin et al, 2000). In addition, where and when animals engage in activity is dictated by their thermal preferences, or the range of temperatures they seek out in a thermally variable environment (Gunderson & Leal, 2016; Hertz et al, 1993; Porter et al, 1973; Sears & Angilletta, 2015; Taylor et al, 2020). Thermal preferences could therefore influence the extent to which native and invasive species overlap in time and space.…”