Magnitude of food reward affects escape behavior and acceptable risk in Balearic lizards, Podarcis lilfordi

During encounters with predators, prey must balance the degreeof risk against the loss of fitness-enhancing benefits suchas feeding and social activities. Most studies of tradeoffsbetween risk and cost of escaping have measured flight initiationdistance and time to emerge from refuge, for which theory providesrobustly supported predictions. Tradeoffs involving other aspectsof encounters, including distance fled and time between escapeand return to a food source, have received little theoreticalor empirical attention. By adapting models of flight initiationdistance and time between entry into refuge and emergence, wepredict effects of predation risk and cost on distance fledand time to return to a source of benefit after fleeing. Actingas simulated predators that approached at a fixed speed, weconducted an experimental field study to test the hypothesesthat flight initiation distance, distance fled, and time toreturn to food by Balearic lizards (Podarcis lilfordi) decreasewith the presence and amount of insect food. Predictions ofthe models were strongly supported, including those for distancefled and return time, but predictions for other cost factorsand predation risk factors remain to be tested.