The effect of resource aggregation at different scales: Optimal foraging behavior of Cotesia rubecula

Resources can be aggregated both within and between patches. In this articl e, we examine how aggregation at these different scales influences the beha vior and performance of foragers. We developed an optimal foraging model of the foraging behavior of the parasitoid wasp Cotesia rubecula parasitizing the larvae of the cabbage butterfly Pieris rapae. The optimal behavior was found using stochastic dynamic programming. The most interesting and novel result is that the effect of resource aggregation within and between patch es depends on the degree of aggregation both within and between patches as well as on the local host density in the occupied patch, but lifetime repro ductive success depends only on aggregation within patches. Our findings ha ve profound implications for the way in which we measure heterogeneity at d ifferent scales and model the response of organisms to spatial heterogeneit y.