Gasteruptiida

The Gasteruptiidae are a family of parasitic wasps that belong to the superfamily Evanioidea.

They are also known as hatchet wasps because of their distinctive hatchet-shaped metasoma (the posterior part of the body).

The Gasteruptiidae are found in most regions of the world, except for the polar areas and some oceanic islands.

They are especially diverse in the tropics and subtropics, where they parasitize the larvae and pupae of various insects, mainly beetles and moths.

The Gasteruptiidae have a long evolutionary history, dating back to the Jurassic period, and have several fossil relatives in the Mesozoic era.

The Gasteruptiidae are currently divided into two subfamilies: Hyptiogastrinae and Gasteruptiinae, with about 300 described species in 40 genera.

The Hyptiogastrinae are mostly small and dark-colored wasps, with a short and broad metasoma.

The Gasteruptiinae are larger and more colorful, with a long and narrow metasoma.

The Gasteruptiidae have some unique morphological features, such as the presence of a median carina (a ridge) on the mesoscutum (the dorsal part of the middle segment of the body), the absence of a propodeal spiracle (an opening for breathing) on the propodeum (the first segment of the metasoma), and the presence of a large ovipositor (an organ for laying eggs) that can be longer than the body.

The Gasteruptiidae are solitary wasps that do not form colonies or nests.

They are active during the day and can be seen flying around flowers or vegetation, searching for hosts.

They use their ovipositor to inject eggs into the body of their hosts, which they usually find by following chemical cues or vibrations.

The eggs hatch inside the host and the larvae feed on the host's tissues, eventually killing it.

The larvae then pupate inside or outside the host's body, depending on the species.

The adult wasps emerge from the pupae and mate, completing their life cycle.

The Gasteruptiidae are important natural enemies of many insect pests, and some species have been used as biological control agents.

They are also of interest to scientists who study the evolution, diversity, and behavior of parasitic wasps.