Trophic and guild interactions in biological control

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Biological control is the use of natural enemies (pathogens, predators, parasites) to suppress a pest population. It is a viable and sustainable alternative to synthetic pesticides. My research is aimed at identifying some of the governing ecological principles and mechanisms of multispecies interactions within arthropod communities found in agroecosystems. From an applied perspective, this research is essential because negative interactions between natural enemies may compromise the effectiveness of biological control programs. The present project will address fundamental and applied questions related to intraguild interactions (i.e. interactions between species at the same trophic level that share the same resource) and host behavior manipulation by parasitic wasps. Using approaches in molecular ecology and behavioral ecology, I wish to identify and quantify ecological and abiotic factors that determine the incidence of predation among species of aphid predators, as well as between predators and parasitic wasps in soybean fields. A second axis of my program relates to strategies evolved by parasitic wasps to exploit their host, and the impact of altered behaviors may have on biological control. We have recently observed that a parasitic wasp induces its coccinellid host to behave as a "bodyguard": the host remains close to the parasitoid pupae and displays a range of aggressive/defensive behaviors that protect parasitoid cocoon against its natural enemies. Furthermore, the coccinellids often recover from parasitism. I plan to answer three important questions on the host behavior manipulation. First, to what extent does parasitism impair coccinellid fitness? Second, are coccinellids recovering from parasitism abundant in nature? Finally, from an applied perspective, do parasitized coccinellids have intrinsically the same capacity to regulate aphid populations as unparasitized conspecifics under field conditions?