Variable Patch Times and the Functional Response of Leptopilina boulardi (Hymenoptera: Eucoilidae)

The functional response of Leptopilina boulardi</it> Barbotin et al. to variations in density of its major natural host, Drosophila melanogaster</it> Meigen, was examined in the laboratory. A behavioral criterion was used to assess attempts by parasitoid females to leave experimental arenas; a patch visit was considered terminated whenever a searching female left the host medium for over 5 min. The results demonstrate density-dependent oviposition behavior in L. boulardi</it>, apparently stemming from a tendency by parasitoid females to spend longer periods of time in patches containing higher densities of hosts, and to emigrate quickly from patches of low host density. However, the form of the functional response was ambiguous. Allowing parasitoid search times to vary among patches changes the spatial frame of functional response measurements and complicates their interpretation; a number of these complications are discussed.