Apocrita is a suborder of insects in the order Hymenoptera.
The Apocrita include wasps, bees and ants, and are comprised of many families. They include the most advanced Hymenoptera and are distinguished from the Symphyta by the narrow waist joining two segments of the abdomen. The ovipositor of the female either extends freely or is retracted, and is converted into a sting for both for defense and for paralyzing prey. Larvae are legless, and may feed either inside a host or in a nest.
The Apocrita consist of two groups, the parasitica and the aculeata. The parasitica comprise the largest group of Hymenoptera insects, with respective members parasitizing every other species of insect. Most are small, with the ovipositor adapted for piercing. In some hosts the parasites induce metamorphosis prematurely, and in others it is prolonged. There are even species that are parasitic on other parasites. The parasitica lay their eggs inside another insect (egg, larva or pupa) and the parasitic larvae grow and develop within that host. The host is killed when the parasites near maturity. Many parasitic Hymenoptera are used as biological control agents to control pests, such as flies and weevils.
The term parasitoid was coined in 1961 by R R Askew to describe the strategy in which during its development, the parasite lives in or on the body of a single host individual, eventually killing that host. The adult parasitoid is free-living.
The aculeata includes those species in which the female’s ovipositor is modified into a stinger; these include the familiar ants, bees and wasps. Among the non-social Apocrita, larvae are fed with captured (parasitized) prey or may be fed pollen and nectar. The social Apocrita feed their young pollen, nectar, and as they mature perhaps seeds, fungi, or even non-viable eggs (ants).