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

Abstract

Superparasitism is an adaptive strategy in solitary parasitoids, yet insufficient evidence confirms this in gregarious ones. We here ask whether the gregarious parasitoid Oomyzus sokolowskii is able to discriminate in attack and progeny allocation between parasitized and unparasitized Plutella xylostella larvae, 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 that O. sokolowskii females may adjust their oviposition decisions on progeny allocation in response to parasitized P. xylostella larvae to maximize their fitness gains from superparasitism.

Effect of maternal age on primary and secondary sex ratios in the ectoparasitoid wasp Pachycrepoideus vindemmiae

“…The haplodiploid sex determination method enables female wasps to manipulate the sex of their progeny, and to decide whether to lay a male egg or a female egg during self‐superparasitism (Ito & Yamada, 2014; Mackauer & Chow, 2016; Li et al, 2019; Liu et al, 2021). Previously parasitized hosts are often of poorer quality than healthy, unparasitized hosts (van Lenteren, 1981).…”