Evolution of Host Selection in Parasitoids: Does the State of the Parasitoid Matter?

A state-variable theory for parasitoid host-acceptance decisions is developed. In this theory, the state variable is the egg complement at any particular time. Decisions are determined by the maximization of Darwinian fitness, which involves both survival and reproduction in a stochastic world. The state-variable theory is compared with simpler theories based on rate maximization. In some circumstances, both theories predict the same host-acceptance patterns; but for wide ranges of biologically meaningful parameters, the predictions of the two theories differ.