Apocrita

Apocrita is a suborder of the insect order Hymenoptera that includes most of the wasps, bees, and ants. A defining feature is a narrow waist created by a constriction between the thorax and the abdomen. In Apocrita the first abdominal segment is fused to the thorax to form the propodeum, and the remaining abdominal segments form a petiole (and in some lineages a post-petiole) before the main metasomal abdomen. This constricted connection distinguishes Apocrita from the broader thorax-abdomen junction seen in the related group Symphyta (sawflies).

Apocrita are holometabolous insects with chemosensory and chewing mouthparts, and wings that are typically coupled by hamuli. They display a wide range of life histories, but parasitoidism is especially prominent: many families, such as Ichneumonidae and Braconidae, have larvae that develop inside or on other arthropods. Other Apocrita include social and solitary wasps, ants, and bees. Ants (Formicidae) and many bees (within Apoidea) are highly eusocial, forming colonies with reproductive division of labor, although social behavior is absent in many species.

Taxonomy and diversity: The suborder comprises numerous families across multiple superfamilies, including Vespoidea (social wasps and relatives), Apoidea (bees and related wasps), and Ichneumonoidea (parasitoid wasps), among others. Ecologically, Apocrita are widespread and play key roles in pollination, natural pest control, and trophic interactions within ecosystems.

Fossil record and evolution: The Apocrita first appear in the mid-Cretaceous, with the evolution of a structured waist contributing to diversification by enabling a variety of parasitic, predatory, and social strategies.