Foraging efficiency and outcomes of interactions of two pupal parasitoids attacking the invasive spotted wing drosophila

In this study, we evaluated their foraging efficiency when attacking D. suzukii infesting cherry fruit in a laboratory cage experiment; and we examined their potential interspecific interactions, including outcomes of intrinsic competition, host discrimination, and the impact of their interaction on pest control. We show that both parasitoids readily parasitized D. suzukii pupae located inside fruit or buried in soil. However, T. drosophilae was more efficient than P. vindemiae and that parasitism by either parasitoid species was higher in the fruit than in the soil. Generally, the parasitoid species that oviposited first in the host out-competed the later parasitoid in multi-parasitized hosts, we assume, through physiological suppression. Both parasitoids discriminated against hosts parasitized previously by the other species. In an additive-series design experiment with single (D. suzukii) or two (D. suzukii and D. melanogaster Meigen) host species, T. drosophilae performed similarly regardless of the presence of a competitor, while P. vindemiae achieved a higher parasitism when present alone. The observed parasitism when the two parasitoid species were present together was always lower than the expected one, assuming each species acted independently. This indicates a negative effect by P. vindemiae on interspecific competition on host suppression. Graphical abstract Highlights
Source: Biological Control - Category: Biology Source Type: research