Potential competitive outcomes among three solitary larval endoparasitoids as candidate agents for classical biological control of Drosophila suzukii

This study first compared the developmental rates of early immature stages of the three parasitoids and then evaluated their potential interactions, including elimination of competitors in intrinsic competition, interspecific discrimination of previously parasitized hosts, and the outcomes of interspecific competition at three host densities (5, 15 or 30 host larvae). On average, L. japonica eggs hatched first, followed by A. japonica and then G. brasiliensis. All three species exhibited interspecific competition after egg hatch through physical combat or in some cases physiological suppression, with L. japonica out-competing the other two parasitoid species in multi-parasitized hosts. Ganaspis brasiliensis adults discriminated strongly against hosts previously parasitized by L. japonica, and A. japonica adults discriminated against hosts previously parasitized by L. japonica, but L. japonica did not discriminate against hosts parasitized by A. japonica. Regardless of host density, the observed parasitism when both A. japonica and L. japonica were present was lower than expected, a likely consequence of interspecific competition, but the combined impacts on host suppression by L. japonica and G. brasiliensis were additive, likely due to strong interspecific discrimination by G. brasiliensis.Graphical abstractSingle vs. two species release in an additive design: the combined impacts on the suppression of host Drosophila suzukii were negative by Asobara japonica (AJ) and Leptop...

Source: Biological Control - December 12, 2018 Category: Biology Source Type: research