Prey often respond to predator presence by increasing their use of refuges. However, because the use of refuges may entail several costs, the decision of when to come out from a refuge should be optimized. In some circumstances, if predators remain waiting outside the refuge and try new attacks or if predator density increases, the prey may suffer successive repeated attacks in a short time. Successive attacks may represent an increase in the risk of predation, but the costs of refuge use also

more »

... ay increase with time spent in the refuge. Thus, prey should make multiple related decisions on when to emerge from the refuge after each new attack. We simulated in the field repeated predatory attacks to the same individuals of the lizard Lacerta monticola and specifically examined the variation in successive times to emergence from a refuge under different thermal conditions (i.e., different costs of refuge use). The results showed that risk of predation but also thermal costs of refuge use affected the emergence decisions. Lizards increased progressively the duration of time spent in the refuge between successive emergence times when the costs of refuge use were lower, but tended to maintain or to decrease the duration of time spent in the refuge between successive emergence times when cost of refuge use increased. Additionally, lizards that entered the refuge with higher body temperatures had overall emergence times of longer duration. Optimization of refuge use and flexibility in the antipredator responses might help lizards to cope with increased predation risk without incurring excessive costs of refuge use.