Interspecific competition in Trichopria anastrephae parasitism (Hymenoptera: Diapriidae) and Pachycrepoideus vindemmiae (Hymenoptera: Pteromalidae) parasitism on pupae of Drosophila suzukii (Diptera: Drosophilidae)

Abstract

Trichopria anastrephae Lima and Pachycrepoideus vindemmiae (Rondani) naturally occur together with the pest Drosophila suzukii (Matsumura) in Brazil. Due to their co-occurrence, it is important to understand competitive interactions between these pupal parasitoids and how this may impact D. suzukii parasitism levels. Thus, the aim of the study was to evaluate the interspecific competition between T. anastrephae and P. vindemmiae. Bioassays were performed with and without time advantage, with different exposure (treatments) of D. suzukii pupae to parasitoid species. Verified that there was a higher parasitism and emergence rate of T. anastrephae adults. This was not observed for P. vindemmiae that decreases the parasitism rate in the presence of T. anastrephae. In strawberry fruits bioassay, T. anastrephae females showed capacity to parasitize pupae of D. suzukii inside strawberry fruits. However, P. vindemmiae had a lower parasitism rate and consequently, fewer insects emerged when used alone or associated with the presence of T. anastrephae. Therefore, we can conclude that there is interspecific competition between T. anastrephae and P. vindemmiae in D. suzukii pupae, with T. anastrephae having a higher competitive advantage.