Apocrita

Apocrita is a suborder of insects in the order Hymenoptera. It includes wasps, bees, and ants, and consists of many families. It contains the most advanced hymenopterans and is distinguished from Symphyta by the narrow "waist" (petiole) formed between the first two segments of the actual abdomen; the first abdominal segment is fused to the thorax, and is called the propodeum. Therefore, it is general practice, when discussing the body of an apocritan in a technical sense, to refer to the mesosoma and metasoma (or gaster) rather than the "thorax" and "abdomen", respectively. The evolution of a constricted waist was an important adaption for the parasitoid lifestyle of the ancestral apocritan, allowing more maneuverability of the female's ovipositor. The ovipositor either extends freely or is retracted, and may be developed into a stinger for both defense and paralyzing prey. Larvae are legless and blind, and either feed inside a host (plant or animal) or in a nest cell provisioned by their mothers. Apocrita has historically been split into two groups, Parasitica and Aculeata. Aculeata is a clade whose name is in standard use. "Parasitica" is not a clade, as it is paraphyletic: the clade would contain the Aculeata. "Parasitica" is therefore a rankless grouping in many present classifications, if it appears at all. Parasitica comprises the majority of hymenopteran insects, its members living as parasitoids. Most species are small, with the ovipositor adapted for piercing. In some hosts, the parasitoids induce metamorphosis prematurely, and in others it is prolonged. There are even species that are hyperparasites, or parasitoids on other parasitoids. The Parasitica lay their eggs inside or on another insect (egg, larva or pupa) and their larvae grow and develop within or on that host. The host is nearly always killed. Many parasitic hymenopterans are used as biological control...