Using Cox's proportional hazard models to implement optimal strategies: Anexample from behavioural ecology

Simple behavioural rules, or "rules of thumb", which lead to behaviour that closely approximates an optimal strategy, have generated a lot of recent i nterest in the field of foraging behaviour. In this paper, we derive rules of thumb from a stochastic simulation model in which the foragers behave op timally. We use a particular biological system: the patch leaving behaviour of a parasitoid. We simulate parasitoids whose patch leaving behaviour is determined by a stochastic dynamic programming (SDP) model, while allowing parasitoids to make mistakes in their estimation of host density when arriv ing in a patch. We use Cox's proportional hazards models to obtain statisti cal rules of thumb from the simulated behaviour. This represents the first use of a proportional hazard approximation to generate rules of thumb from a complex optimal strategy. (C) 2001 Elsevier Science Ltd. All rights reser ved.