parasitoid

Parasitoid waspsParasitoids, which parasitize other arthropods by depositing eggs in the pupae, larvae, or eggs of their hosts. (Left) A female ichneumonid, or ichneumon, wasp (family Ichneumonidae) lays her eggs in the host larvae by means of her ovipositor. (Right) A wasp from genus Trichogramma (family Trichogrammatidae) develops within a host egg and emerges as an adult.

parasitoid, an insect whose larvae feed and develop within or on the bodies of other arthropods. Each parasitoid larva develops on a single individual and eventually kills that host. Most parasitoids are wasps, but some flies and a small number of beetles, moths, lacewings, and even one caddisfly species have evolved to be parasitoids. Parasitoids alone number about 68,000 named species, and most have yet to be named and described. Realistic estimates of the total number of described and undescribed parasitoid species are about 800,000.

This article was most recently revised and updated by John P. Rafferty.