Evaniidae is a family of parasitoid wasps also known as ensign wasps, nightshade wasps, hatchet wasps, or cockroach egg parasitoid wasps. They number around 20 extant genera containing over 400 described species, and are found all over the world except in the polar regions. The larvae of these solitary wasps are parasitoids that feed on cockroaches and develop inside the egg-cases, or oothecae, of their hosts.
Evaniidae
Illustration of Evania appendigaster (lower right) and its pupa (upper right) as parasitoids of the American cockroach (Periplaneta americana)
Ensign wasp in amber
Parasitoid wasps are a large group of hymenopteran superfamilies, with all but the wood wasps (Orussoidea) being in the wasp-waisted Apocrita. As parasitoids, they lay their eggs on or in the bodies of other arthropods, sooner or later causing the death of these hosts. Different species specialise in hosts from different insect orders, most often Lepidoptera, though some select beetles, flies, or bugs; the spider wasps (Pompilidae) exclusively attack spiders.
Megarhyssa macrurus (Ichneumonidae), a parasitoid, ovipositing into its host through the wood of a tree. The body of a female is c. 2 inches (50 mm) long, with an ovipositor c. 4 inches (100 mm) long.
Spider wasp (Pompilidae), an idiobiont, carrying a jumping spider she has just paralysed back to her nest, where she will lay an egg on it.
...but endoparasitic koinobiont wasp larvae eventually fill its body and kill it.
Hornworm with parasitic wasp cocoons
