Behavioural and physiological ecology of reptiles

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Physiology has pervasive effects on most facets of ecology. Recently, it has been argued that the temperature and body size dependence of metabolic rate could explain the latitudinal gradient of increasing biodiversity from the poles to the equator. It was also proposes that the temperature and body size dependence of metabolic rate controls ecological processes at all levels of organization from individuals to the biosphere. While this new metabolic theory of ecology has stirred much controversy, it is clear that physiological processes, including metabolic rate, are temperature dependent. The vast majority of animals are ectotherms and, unlike endotherms, have limited capacity for buffering the ubiquitous effects of body temperature on all of their developmental, physiological, and behavioural processes. Thus, since reptiles are ectotherms, variation in their body temperature ultimately has a significant impact on fitness, but this impact remains only partially understood. Ectotherms use behavioural thermoregulation to avoid reduced capacities associated with excessively high or low body temperatures. Reptiles regulate body temperature mainly through behaviour and choice of microclimate. Thus, thermoregulation is tightly linked to habitat selection and to behaviour. Because thermoregulation affects fitness through the temperature dependence of physiological processes, we can establish relationships between behavioural thermoregulation, physiology, and fitness in reptiles. My long-term research objective is to decipher how behaviour and phenotype, modulated by physiological constraints, affect whole-organism performance and, thus, fitness-related life-history traits. I use a functional evolutionary approach and most of my work integrates controlled laboratory experiments with field observations.