Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic. Females typically have a special ovipositor for inserting eggs into hosts or places that are otherwise inaccessible. This ovipositor is often modified into a stinger. The young develop through holometabolism — that is, they have a wormlike larval stage and an inactive pupal stage before they reach adulthood.
Sawflies are wasp-like insects that are in the suborder Symphyta within the order Hymenoptera, alongside ants, bees, and wasps. The common name comes from the saw-like appearance of the ovipositor, which the females use to cut into the plants where they lay their eggs. The name is associated especially with the Tenthredinoidea, by far the largest superfamily in the suborder, with about 7,000 known species; in the entire suborder, there are 8,000 described species in more than 800 genera. Symphyta is paraphyletic, consisting of several basal groups within the order Hymenoptera, each one rooted inside the previous group, ending with the Apocrita which are not sawflies.
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 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 or in a nest cell provisioned by their mothers.
The Ichneumonidae, also known as ichneumon wasps, ichneumonid wasps, ichneumonids, or Darwin wasps, are a family of parasitoid wasps of the insect order Hymenoptera. They are one of the most diverse groups within the Hymenoptera with roughly 25,000 species described as of 2016. However, this likely represents less than a quarter of their true richness as reliable estimates are lacking, along with much of the most basic knowledge about their ecology, distribution, and evolution. It is estimated that there are more species in this family than there are species of birds and mammals combined. Ichneumonid wasps, with very few exceptions, attack the immature stages of holometabolous insects and spiders, eventually killing their hosts. They thus fulfill an important role as regulators of insect populations, both in natural and semi-natural systems, making them promising agents for biological control.
The Tiphiidae are a family of large, solitary wasps whose larvae are parasitoids of various beetle larvae, especially those in the superfamily Scarabaeoidea. Until recently, this family contained several additional subfamilies, but multiple studies have independently confirmed that these comprise a separate lineage, and are now classified in the family Thynnidae.
Xiphydriidae are a family of wood wasps that includes around 150 species. They are located all over the world including North and South America, Australia, Europe, and others. Xiphydriidae larvae are wood borers in dead trees or branches of a range of trees. They are characterized as having long and skinny necks with dome-shaped heads. The oldest fossils of the group are from the mid Cretaceous.
The Gasteruptiidae are one of the more distinctive families among the apocritan wasps, with surprisingly little variation in appearance for a group that contains around 500 species in two subfamilies and with 6 genera worldwide. They are members of Evanioidea.
The Chalcididae are a moderate-sized family within the Chalcidoidea, composed mostly of parasitoids and a few hyperparasitoids. The family is apparently polyphyletic, though the different subfamilies may each be monophyletic, and some may be elevated to family status in the near future. As presently defined, there are over 85 genera and over 1460 species worldwide. They are often black with yellow, red, or white markings, rarely brilliantly metallic, with a robust mesosoma and very strong sculpturing. The hind femora are often greatly enlarged, with a row of teeth or serrations along the lower margin.
The Leucospidae are a specialized group of wasps within the superfamily Chalcidoidea, that are ectoparasitoids of aculeate wasps or bees. They are typically mimics of bees or stinging wasps, often black with yellow, red, or white markings, sometimes metallic, with a robust mesosoma and very strong sculpturing. The hind femora are often greatly enlarged, with a row of teeth or serrations along the lower margin as in Chalcididae. The wing has a longitudinal fold. The female ovipositor is sometimes short, but if not, it is recurved and lies along the dorsal side of the metasoma, a unique feature. The males are also unusual, in the fusion of many of the metasomal segments to form a capsule-like "carapace".
The Stephanidae, sometimes called crown wasps, are a family of parasitoid wasps. They are the only living members of the superfamily Stephanoidea. Stephanidae has at least 345 living species in 11 genera. The family is considered cosmopolitan in distribution, with the highest species concentrations in subtropical and moderate climate zones. Stephanidae also contain four extinct genera described from both compression fossils and inclusions in amber.
Megalyroidea is a small hymenopteran superfamily of wasps that includes a single family, Megalyridae, with eight extant genera and 49 described species. Modern megalyrids are found primarily in the southern hemisphere, though fossils have only been found in the northern hemisphere. The most abundant and species-rich megalyrid fauna is in Australia. Another peak of diversity appears to be in the relict forests of Madagascar, but most of these species are still undescribed.
The Evanioidea are a small hymenopteran superfamily that includes three extant families, two of which are much more closely related to one another than they are to the remaining family, Evaniidae. The rich fossil record, however, helps fill in the gaps between these lineages. They all share the trait of having the metasoma attached very high above the hind coxae on the propodeum.
Evaniidae is a family of parasitoid wasps also known as ensign wasps, nightshade wasps, hatchet wasps, or cockroach egg parasitoid wasps. They number around 20 extant genera containing over 400 described species, and are found all over the world except in the polar regions. The larvae of these solitary wasps are parasitoids that feed on cockroaches and develop inside the egg-cases, or oothecae, of their hosts.
The Sierolomorphidae are a family of 13 extant species of wasps, in the genera Sierolomorpha and Proscleroderma, mostly found in the Northern Hemisphere. They are rare and very little is known of their biology. A fossil species Loreisomorpha nascimbenei has also been placed in the family.
Microgastrinae is a subfamily of braconid wasps, encompassing almost 3,000 described species, with an estimated 30,000–50,000 total species. This makes it one of the richest subfamilies with the most species of parasitoid wasps.
The Cheloninae are a cosmopolitan subfamily of braconid parasitoid wasps.
The Ibaliidae are a small family of the hymenopteran superfamily Cynipoidea. Ibaliidae differ from most of the cynipoids by the larvae being parasitoids on other wasp larvae in the group Siricidae. The Ibaliidae comprise three extant genera of fairly large wasps, with a total of 20 species, and is a sister group to the rest of the cynipoids except the small subfamily Austrocynipidae.
The Thynnidae are a family of large, solitary wasps whose larvae are almost universally parasitoids of various beetle larvae, especially those in the superfamily Scarabaeoidea. Until recently, the constituents of this family were classified in the family Tiphiidae, but multiple studies have independently confirmed that thynnids are a separate lineage.
Pristaulacus is a cosmopolitan genus of aulacid wasps in the Hymenopteran family, Aulacidae. There are more than 190 described species in Pristaulacus. Most host records for Pristaulacus are wood-boring beetles.
Aulacus is a genus of aulacids, ensigns, and gasteruptiids in the family Aulacidae. There are 77 species of Aulacus.
