Optimality theory predicts that, provided that a larva resulting from superparasitism has some chance of winning the competition with the other larvae present in the host, under certain conditions, solitatry parasitoids should resort to superparasitism. Both theoretical and experimental studies have shown that the life expectancy of the parasitoid has a strong influence on the decision to reject or to accept superparasitism. In many species, life expectancy on its turn depends on the feeding behaviour of the parasitoids, which have to forage for non-host food (mainly plant materials), for the maintenance of their energy reserves. As many solitary parasitoids do not find non-host food in their host patches, they have to choose at each instant whether to search for food or to search for hosts. In this paper, we develop a stochastic dynamic programming model to study the behavioural choice between host and food searching, and its consequences for the acceptance and rejection of superparasitism. We study the influence of habitat quality and parasitoid physiological state on the optimal choice. The model predicts that the crucial point determining the optimal strategy is the balance between egg-and time-limitation.
