Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamily Apoidea. They are currently considered a clade, called Anthophila. There are over 20,000 known species of bees in seven recognized biological families. Some species – including honey bees, bumblebees, and stingless bees – live socially in colonies while most species (>90%) – including mason bees, carpenter bees, leafcutter bees, and sweat bees – are solitary.
Apidae is the largest family within the superfamily Apoidea, containing at least 5700 species of bees. The family includes some of the most commonly seen bees, including bumblebees and honey bees, but also includes stingless bees, carpenter bees, orchid bees, cuckoo bees, and a number of other less widely known groups. Many are valuable pollinators in natural habitats and for agricultural crops.
The superfamily Apoidea is a major group within the Hymenoptera, which includes two traditionally recognized lineages, the "sphecoid" wasps, and the bees. Molecular phylogeny demonstrates that the bees arose from within the traditional "Crabronidae", so that grouping is paraphyletic, and this has led to a reclassification to produce monophyletic families.
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.
Halictidae is the second-largest family of bees with nearly 4,500 species. They are commonly called sweat bees, as they are often attracted to perspiration. Halictid species are an extremely diverse group that can vary greatly in appearance. These bees occur all over the world and are found on every continent except Antarctica. Usually dark-colored and often metallic, halictids are found in various sizes, colors and patterns. Several species are all or partly green and a few are red, purple, or blue. A number of them have yellow markings, especially the males, which commonly have yellow faces, a pattern widespread among the various families of bees. The family is one of many with short tongues and is best distinguished by the arcuate basal vein found on the wing. Females in this family tend to be larger than the males. They are the group for which the term 'eusocial' was first coined by entomologist, Suzanne Batra.
Vespoidea is a superfamily of wasps in the order Hymenoptera. Vespoidea includes wasps with a large variety of lifestyles including eusocial, social, and solitary habits, predators, scavengers, parasitoids, and some herbivores.
The Sphecidae are a cosmopolitan family of wasps of the suborder Apocrita that includes sand wasps, mud daubers, and other thread-waisted wasps.
The Crabronidae are a large paraphyletic group of wasps, including nearly all of the species formerly comprising the now-defunct superfamily Sphecoidea. It collectively includes well over 200 genera, containing well over 9000 species. Crabronids were originally a part of the Sphecidae, but the latter name is now restricted to a separate family based on what was once the subfamily Sphecinae. Several of the subfamilies of the Crabronidae are often treated as families in their own right, as is true of the most recent phylogenies.
The Stenotritidae is the smallest of all formally recognised bee families, with only 21 species in two genera, all of them restricted to Australia. Historically, they were generally considered to belong in the family Colletidae, but the stenotritids are presently considered their sister taxon, and deserving of family status. Of prime importance is that the stenotritids have unmodified mouthparts, whereas colletids are separated from all other bees by having bilobed glossae.
The subfamily Dasypodainae is a small subfamily of melittid bees, with more than 100 species in eight genera, found in Africa and the northern temperate zone, primarily in xeric habitats.
Meganomiinae is a subfamily of melittid bees, with 10 species in four genera, found only in Africa, primarily in xeric habitats, with the distributional limits in Yemen and Madagascar. They are rather different in appearance from the other groups of past/present melittids, being large bees (10–22 mm), mostly black with strong yellow markings, resembling anthidiine megachilids. Males of this subfamily are known to have hidden sterna.
Heterogynaidae is a minor and disputed lineage of small spheciform wasps occurring in Madagascar, Botswana, Turkmenistan, Oman, the United Arab Emirates, and the Eastern Mediterranean area. The majority are dark in color and range in size from approximately 1.5 to 5.0 mm. Most specimens have been collected in arid climates, but one species from Madagascar is known to occur in a humid forest habitat. Although males have functional wings, heterogynaid females are typically brachypterous, a trait which is unique among spheciform wasps. Wing venation is reduced in both sexes. All species are diurnal, with the exception of H. nocticola. Other aspects of their biology are completely unknown, but details of their morphology have prompted researchers to hypothesize that they may be non-fossorial parasitoids adapted to hunt in tight spaces, such as under tree bark. This is speculative and has not yet been confirmed by actual observations of behavior. It is also possible that modifications of the female metasomal tergum VI and gonostyli may represent a unique prey transport mechanism, but this is also unconfirmed.
Astatinae are a cosmopolitan group of solitary wasps, peculiar for their males having very large compound eyes that broadly meet at the top of the head. The largest genus in this subfamily is Astata, with about half of more than 160 species in the subfamily.
Mellinidae is a small family of wasps, comprising 17 described species in two genera. This group has traditionally been treated as a subfamily within Crabronidae (Mellininae), but recent phylogenomic studies have shown it to be a distinct family.
The subfamily Pemphredoninae also known as the aphid wasps, is a large group in the wasp family Crabronidae, with over 1000 species. Historically, this subfamily has frequently been accorded family status. In some recent phylogenetic analyses, one of the subtribes within this group is the sister lineage to the superfamily Apoidea, and accorded family rank as Ammoplanidae along with Pemphredonidae and Psenidae so as to keep families monophyletic.
Heterotremata is a clade of crabs, comprising those crabs in which the genital openings are on the sternum in females, but on the legs in males. It comprises 68 families in 28 superfamilies.
Ammophilinae is a subfamily of thread-waisted wasps in the family Sphecidae. There are about 6 genera and more than 320 described species in Ammophilinae.
Melittidae is a small bee family, with over 200 described species in three subfamilies. The family has a limited distribution, with all described species restricted to Africa and the northern temperate zone.
Psenini is a tribe of aphid wasps in the family Crabronidae. There are about 11 genera and at least 460 described species in Psenini.
Miscophus is a genus of square-headed wasps in the family Crabronidae. There are more than 180 described species in Miscophus.
