Host range and multitrophic interactions between the parasitoid Cotesia vanessae (Hymenoptera: Braconidae) and Noctuidae (Lepidoptera) hosts in North America

Caterpillars in the family Noctuidae are important crop pests. After discovering the parasitoid Cotesia vanessae in the Nearctic region, which was previously only known from the Palearctic and Afrotropic regions, I investigated its fundamental host range on North American Lepidoptera and found that it could parasitize a large number of species of Noctuidae. Its fitness varied among host species, and Plusiinae species appeared to be the best hosts. Nearly all hosts in this experiment were reared on McMorran diet, which appeared to have varying suitability among Lepidoptera species. Through a second experiment, I showed that the fitness of the parasitoid and that of its host varied according to host food quality. Thus, parasitoid fitness on different hosts is partly conditioned by diet quality. This study shows that C. vanessae can parasitize a large number of Noctuidae and can be easily mass-reared, which could make it an ideal biological control agent.Alberta Conservation Association (Grants in Biodiversity) and Canola Council of Canada (Canola Agronomic Research Program