Submitted to: Journal of Entomological Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/24/2006
Publication Date: 10/1/2006
Citation: Tillman, P.G. 2006. Comparison of searching behavior of parasitoid, Toxoneuron nigriceps Vierick, for three tobacco herbivores. Journal of Entomological Science. 41(4):321-328. Interpretive Summary: Populations of tobacco budworms can reach economically damaging levels in cotton. Cardiochiles nigriceps is a parasitic wasp that can contribute substantially to the biological control of tobacco budworms in cotton when tobacco is available as a nursery for these natural enemies. In this study, the host-searching behavior of females of this parasitic wasp was observed for tobacco budworms, corn earworms, and tobacco hornworms on tobacco plants. Overall, C. nigriceps females preferred tobacco budworm to corn earworm and tobacco hornworm and laid more eggs in tobacco budworm, the normal host of C. nigriceps, than in corn earworm and tobacco hornworm, two non-hosts for this parasitoid. This data shows that Cardiochiles nigriceps females would not be adversely affected by the presence of nonhosts in a tobacco nursery for this parasitoid in cotton.
Technical Abstract: Host searching behavior of Cardiochiles nigriceps Vierick (Hymenoptera: Braconidae) was observed in the field for three tobacco insect pests, Heliothis virescens (Fabricius)(Lepidoptera: Noctuidae), Helicoverpa zea (Boddie)(Lepidoptera: Noctuidae), and Manduca sexta L. (Lepidoptera: Spingidae). Hovering, searching, and oviposition were the three main host searching behaviors observed and recorded using a Psion Organizer II with Observer software. Herbivore-induced plant volatiles elicited a hovering response important in host plant and host feeding-site location. Host cues elicited a host searching response crucial for finding hosts on the plant. Both herbivore-induced plant volatiles and host cues provided host-specific information to C. nigriceps females.