Emerald cockroach wasp

Description

Ampulex compressa is a solitary wasp of the family Ampulicidae. It is known for its unusual reproductive behavior, which involves stinging a cockroach and using it as a host for its larvae. It thus belongs to the entomophagous parasites. The wasp is mostly found in the tropical regions of Africa, South Asia, Southeast Asia, and the Pacific islands. The flying wasps are more abundant in the warm seasons of the year. A. compressa was introduced to Hawaii by F.X. Williams in 1941 as a method of biocontrol. This has been unsuccessful because of the territorial tendencies of the wasp, and the small scale on which they hunt. The species is also found in the Brazilian states of São Paulo and Rio de Janeiro. A. compressa likely arrived in the country through the ports of Santos and Rio de Janeiro. The wasp has a metallic blue-green body, with the thighs of the second and third pair of legs red. The female is about 22 mm long; the male is smaller and lacks a stinger. Males can be less than half of a female in size if emerging from a smaller or a superparasitized host. The species undergoes four larval stages, where the initial younger larvae can be seen as external hemolymph-feeders on the paralysed roach's leg, and the last instar feeds internally. Upon pupation it produces a chocolate-coloured, thick, spindle-shaped cocoon which can be found inside the dead cockroach within the burrow.