A MODEL OF RISK-SENSITIVE FORAGING FOR A REPRODUCING ANIMAL

A model in which a foraging animal can reproduce if its energy reserves reach a critical level is presented. The animal has the choice of two foraging options which have the same mean net gain but differ in their variance. The policy that maximizes expected lifetime reproductive success was found. The pattern of risk-sensitive behaviour predicted by this model was compared with that predicted by a similar model in which no reproduction occurs and the optimality criterion is to minimize the probability of death. The two models give different predictions. This serves to emphasize that there is no single model of risk-sensitive foraging. Risk-sensitivity results from a non-linear relationship between fitness and energy reserves. This relationship provides a single principle that is common to all models of risk-sensitive foraging. Not surprisingly, the form of the relationship will depend on the biology of the animal under consideration. © 1991 The Association for the Study of Animal Behaviour.