Oviposition strategy for superparasitism in the gregarious parasitoidOomyzus sokolowskii(Hymenoptera: Eulophidae)

Abstract

AbstractSuperparasitism is an adaptive strategy in solitary parasitoids, yet insufficient evidence confirms this in gregarious ones. We here ask whether the gregarious parasitoidOomyzus sokolowskiiis able to discriminate in attack and progeny allocation between parasitized and unparasitizedPlutella xylostellalarvae, and how the parasitoid allocates brood size and sex to superparasitized hosts due to some circumstances. We found that female parasitoids preferred unparasitized to parasitized host larvae, and allocated a smaller brood with more males in the later than in the former host. Brood size and sex ratio decreased from superparasitized hosts with a 48 h interval since a previous attack compared with one without an interval; they also declined from the host superparasitized by the parasitoid with oviposition experience compared with one without it. Brood size and sex ratio did not differ between the host superparasitized by the same parasitoid as in the first attack and that by a different one. Our findings suggest thatO. sokolowskiifemales may adjust their oviposition decisions on progeny allocation in response to parasitizedP. xylostellalarvae to maximize their fitness gains from superparasitism.