Laboratory adaptation of a native North American parasitoid to an exotic wood-boring beetle: implications for biological control of invasive pests.
Numerous researchers have observed native parasitic Hymenoptera attacking exotic pest species, yet few have documented their potential to adapt to novel hosts. Host-adapted parasitoids may be particularly important in new-association biocontrol programs, especially if their behaviors and physiologies can be affected in such a way as to enhance their virulence on novel hosts. Here, we investigated the potential of the native parasitoid, Ontsira mellipes, to adapt to a novel, invasive cerambycid host, Anoplophora glabripennis, under laboratory conditions. Although not significantly different, there is an apparent increase in parasitism of A. glabripennis larvae (from 45.5 to 65.7%) and in the percentage of pupae eclosing to adults (from 65.1 to 82.9%) between the F1-2 and F68-71 generation parasitoids. Moreover, later generation (F41-44 and F68-71) parasitoids produced significantly more progeny on average than did first-generation (F1-2) parasitoids, and parasitoid generation had no significant effect on the secondary sex ratio or ovipositor length. Results indicate that older generation parasitoids have an increased efficacy in parasitizing and utilizing this novel host. This study demonstrates that continuously rearing of a generalist parasitoid on a newly acquired novel host can enhance host parasitism rates, parasitoid development, and fitness and thus may improve the efficacy of new-association biocontrol.