Prolonged embryonic stage and synchronized life-history of Platygaster robiniae (Hymenoptera: Platygastridae), a parasitoid of Obolodiplosis robiniae (Diptera: Cecidomyiidae)

Abstract

Platygaster robiniae Buhl and Duso (Hymenoptera: Platygastridae) is a gregarious, koinobiont endoparasitoid of the locust gall midge, Obolodiplosis robiniae (Haldeman) (Diptera: Cecidomyiidae). P. robiniae is an egg-larval parasitoid, parasitizing eggs of O. robiniae and emerging from the host larvae. The eggs of the wasp develop monembryonically with a prolonged embryonic stage. After hatching, the parasitoid undergoes only two larval instars, and total development time from egg to adult takes about 28 days to complete. The life cycle of a parasitoid generation is synchronized with that of its host; the adult wasps’ emergence coincides with that of the host, so that they can parasitize the host eggs.