trichogrammatid wasp, (family Trichogrammatidae), any of a group of around 1,000 species of tiny, parasitic chalcid wasps, particularly of the genus Trichogramma. Adults are typically less than 1 mm (0.04 inch) long, with pear-shaped wings having a single vein and fringing hairs. Members of the genus Megaphragma are among the smallest known insects; M. caribea has a body length of about 170 μm (0.007 inch) and M. mymaripenne measures about 200 μm (0.008 inch). Trichogramma are important biological control agents. T. minutum, which is readily cultured in the laboratory, has been successfully employed against various lepidopteran agricultural pests.
See also list of ants, bees, and wasps.
Like most solitary wasps, trichogrammatid wasps are parasitoids, and their endoparasitic larvae feed and develop within the eggs of other arthropods. Females lay their eggs in the eggs of their host. When the wasp larvae hatch inside the host egg, they consume the nutrients and embryo before pupating and emerging as adults. The males of some species spend their entire life cycle within the host egg, dying soon after mating with their sisters in a shared egg.