Behavioral Responses of Female Microplitis tuberculifer to Volatiles from Cotton Plants induced by Herbivores (Hymenoptera: Braconidae)

Chemical defense responses are evoked in plants upon herbivore damage and the volatile compounds induced attract parasitic wasps. Bacillus thuringiensis (Bt), an entomopathogenic bacterium, is a useful control agent for many herbivores. In this study, the behavioral responses of females of the parasitic wasp species, Microplitis tuberculifer (Wesmael 1837) to damage of Bt and non-Bt cotton were compared. M tuberculifer preferred the volatiles induced by Spodoptera exigua (Hubner 1808)-damaged Bt cotton to those induced by similarly damaged non-Bt cotton. However, M tuberculifer was not obviously attracted to either type of intact or artificially damaged cotton, or to cotton damaged by Helicoverpa armigera (Hubner 1803). The parasitoid was more intensely attracted to the volatiles induced by both non-Bt and Bt cotton damaged by S exigua, than to intact cotton. However, the volatiles induced by H armigera-damaged non-Bt and Bt cotton were not attractive to M tuberculifer.