New insights on how temporal variation in predation risk shapes prey behavior

The fact that predators come and go, so that individual prey experience temporal variations in predation risk, is an almost unavoidable aspect of nature. Predation risk routinely varies seasonally1, across lunar cycles2 and diurnal cycles3, or on a moment-to-moment basis4. In spite of its near ubiquity in nature, until recently no theory has focused explicitly on the effects of temporal variation in risk on prey behavior. That is, existing theory has generally taken a static view – contrasting antipredator effort for prey facing constant high versus constant low predation risk. Now, however, a new model by Steven Lima and Peter Bednekoff5 has extended the ‘Risk Spreading Theorem’6, to show that the pattern of temporal variation in predation risk experienced by individual prey can be crucial for understanding patterns of antipredator effort. Their model has produced insights that are important for empiricists because, to date, experiments have not addressed these temporal effects, and because, perhaps more importantly, the model suggests that standard laboratory protocols might err systematically in estimating the importance of predation risk in nature.