Risk Level and Thermal Costs Affect the Choice of Escape Strategy and Refuge Use in the Wall Lizard, Podarcis muralis

Abstract

Animals should tend to adjust the magnitude and characteristics of their escape responses according to the perceived levels of predation risk to cope with risk without incurring excessive costs. We analyze in the field the factors that determine the choice of escape behavior and patterns of refuge use of Wall Lizards under two simulated levels of predation risk and under variable environmental conditions, which may affect risk perception and costs of refuge use. The results show that Wall Lizards adjusted their antipredatory response according to several factors. The threat of predation posed by the predator affected the initial type of response of lizards but not the subsequent escape strategies employed. The escape strategy depended on the vulnerability to be captured (i.e., height on the wall and air temperature) and costs of refuge use (temperature and potential predation by ambush snakes). The initial risk of predation and thermal costs of refuge use affected emergence times from the refuge. The antipredator decisions of Wall Lizards, therefore, were influenced not only by the probability of mortality in the immediate future, such as the initial threat of predation and perceived susceptibility but also by consequences for long-term expected fitness, such as physiological costs of refuge use, and by the eventual risk of mortality associated with the use of unsafe refuges.