Apocrita, one of two suborders of the insect order Hymenoptera, the other being Symphyta. Included in the group are the ants, bees, wasps, braconids, ichneumons, chalcids, nearly all parasitic hymenopterans, and a few other forms. The suborder includes the most highly evolved members of the order and is represented by several thousand species distributed worldwide.
Among most species, the grublike larvae are sedentary forms. They may feed as parasites on other arthropods or within plant structures, or they may be fed by adults within a nest. The base of the adult’s abdomen is constricted, a diagnostic feature of the group. The adults feed mainly on plants, although some species are parasites and others are hyperparasites (that is, they feed on insects that are parasitic on other insects).
Although the suborder includes some species that are destructive to crops—for example, the seed chalcids (Eurytomidae)—the majority of species are beneficial to man. Beneficial members include the bee, which pollinates a great variety of economically important plants; the honeybee (Apis) is also important for the honey it produces; and many species are important as parasites of insect pests. Such parasites include ichneumon, chalcid, pteromalid, figitid, ensign wasp, and bethylid.