An Experimental Test of the Costs of Antipredatory Refuge Use in the Wall Lizard, Podarcis muralis

Abstract

Prey often respond to predator presence by increasing their use of refuges. However, refuge use may have some costs such as lost opportunities for foraging, and also physiological costs, such as hypothermia. Many lizards escape from predators by fleeing into rock crevices, which because of shady and colder conditions decreases their body temperature below required optimal levels. By experimentally increasing the frequency of attacks by a simulated predator (human) toward a group of wall lizards. Podarcis muralis, we examined the hypothesis that lizards may respond to an increase in risk of predation with an increase in refuge use, but that this strategy entails costs to their body condition. At the end of the experimental period, experimental lizards increased the time spent in a refuge after an attack (recovery time), but they had significantly lower relative body mass than control individuals. We suggest that an increase in the time spent in refuges at unfavourable temperatures during the experiment led to a loss of time available for foraging and a diminution of the efficiency of physiological functions, which resulted in loss of mass.