Assessing thermoregulatory behaviour of reptiles: Proximate insights into ultimate causes (#312)
A standard assumption of reptilian metabolism and thermoregulation has centred on their strong reliance on behavioural control over body temperature, due in part to their dependence on the environment for body heat (e.g., ectothermy). Laboratory measurements of thermal preference in animals have been utilised extensively in the fields of ecology and physiology, often for quite divergent purposes. Generally, field studies are interested in assessing costs and trade-offs associated with the behavioural maintenance of core body temperature, as well as predicting preferred body temperatures in nature; physiological studies are geared toward assessing the propensity or existence of inherent central control mechanisms driving the behavioural selection of temperature. Through both laboratory and field measurements, one can approach these questions in an integrative manner and shed light on both the ecological relevance and physiological mechanisms underlying thermoregulation. The advantage that the behavioural assessment of preferred temperature provides over more invasive techniques is that the active selection of temperatures requires intact neurological control. Thus, measurements of preferred temperatures are also ways of asking questions regarding the evolution of the brain's central 'thermostat' as well as the role of the sensory system. This concept of a central 'thermostat' is particularly relevant and lies at the crux between evolutionary of thermoregulation and physiological questions of thermoregulatory homeostasis. Addressing the nature of an animal's central thermostat is relevant to elucidating neural control mechanisms, as well as deducing how natural processes operate and how natural selection has shaped thermal behaviour in the wild. Insightful questions into the motivational status and neurological control of one of the most critical parameters in a reptile’s life (i.e., temperature) can be elucidated through these simple measures.