Possible coexistence of native and exotic parasitoids and their impact on control of Halyomorpha halys
Konopka, J.K., Haye, T., Gariepy, T.D., McNeil, J.N. (2017). Possible coexistence of native and exotic parasitoids and their impact on control of Halyomorpha halys. Journal of Pest Science, [online] 90(4), 1119-1125. http://dx.doi.org/10.1007/s10340-017-0851-2
Plain language summary
In classical biological control, natural enemies of an insect pest are used to reduce the damage caused by the pest. Here we looked at two natural enemies of an invasive insect pest, the brown marmorated stink bug (BMSB), to determine whether the two natural enemies would compete for the host. Competition could reduce the effectiveness of a biological control program, and as such, it is important to understand the interactions between natural enemies that share the same host. In the present study, we investigated competition between Trissolcus japonicus and Anastatus bifasciatus, and determined that the two species can co-exist and that when both species of natural enemy are present, they may increase the suppression of the pest.
Introduction of exotic natural enemies for biological control of invasive pests may disrupt existing ecological interactions, which may influence the outcome of biological control introductions. The interactions between Asian egg parasitoids, proposed as classical biological control agents of the highly polyphagous invasive pest Halyomorpha halys (Stål), and parasitoids native to the introduced area are largely unknown. Therefore, adult and larval interspecific competition between the exotic Trissolcus japonicus (Ashmead) and the European Anastatus bifasciatus (Geoffroy) was assessed (1) by observing aggressive interactions between adults of the two species following parasitization and (2) by providing each parasitoid species with previously parasitized H. halys egg masses at various time intervals. The results suggest that T. japonicus and A. bifasciatus engage in counterbalance competition, with the former being a superior extrinsic competitor (egg guarding and aggressiveness) and the latter being a superior intrinsic competitor (successful development from multiparasitized eggs of all ages). We suggest that the presence of T. japonicus is unlikely to have a negative impact on A. bifasciatus, and that those two species can coexist and potentially act synergistically in the biological control of H. halys.