Hymenoptera

Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described,[2][3] in addition to over 2,000 extinct ones.[4]

Females typically have a special ovipositor for inserting eggs into hosts or places that are otherwise inaccessible. The ovipositor is often modified into a stinger. The young develop through holometabolism (complete metamorphosis)—that is, they have a worm-like larval stage and an inactive pupal stage before they mature.

Hymenoptera
Temporal range: Triassicpresent 235–0 Ma[1]
Sphex pensylvanicus
A digger wasp, Sphex pensylvanicus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
(unranked): Endopterygota
Superorder: Hymenopterida
Order: Hymenoptera
Linnaeus, 1758
Suborders

Apocrita
Symphyta

Etymology

The name Hymenoptera refers to the wings of the insects, but the original derivation is ambiguous.[5]:42 All references agree that the derivation involves the Ancient Greek πτερόν (pteron) for wing. The Ancient Greek ὑμήν (hymen) for membrane provides a plausible etymology for the term because species in this order have membranous wings. However, a key characteristic of this order is that the hind wings are connected to the fore wings by a series of hooks. Thus, another plausible etymology involves Hymen, the Ancient Greek god of marriage, as these insects have "married wings" in flight.

Evolution

The cladogram of external relationships, based on a 2008 DNA and protein analysis, shows the order as a clade, most closely related to endopterygote orders including the Diptera (true flies) and Lepidoptera (butterflies and moths).[6][7][8][9]

part of Endopterygota
Antliophora

Diptera (true flies) Common house fly, Musca domestica

Mecoptera (scorpionflies) Gunzesrieder Tal Insekt 3

Boreidae (snow scorpionflies) Boreus hiemalis2 detail

Siphonaptera (fleas) Pulex irritans female ZSM.jpg

Trichoptera (caddisflies) Sericostoma.personatum

Lepidoptera (butterflies and moths) Tyria jacobaeae-lo.jpg

Hymenoptera (sawflies, wasps, ants, bees) AD2009Sep09 Vespula germanica 03

Hymenoptera originated in the Triassic, with the oldest fossils belonging to the family Xyelidae. Social hymenopterans appeared during the Cretaceous.[10] The evolution of this group has been intensively studied by Alex Rasnitsyn, Michael S. Engel, and others.[11]

This clade has been studied by examining the mitochondrial DNA.[12] Although this study was unable to resolve all the ambiguities in this clade, some relationships could be established. The Aculeata, Ichneumonomorpha, and Proctotrupomorpha were monophyletic. The Megalyroidea and Trigonalyoidea are sister clades as are the Chalcidoidea+Diaprioidea. The Cynipoidea was generally recovered as the sister group to Chalcidoidea and Diaprioidea which are each other's closest relations. The cladogram is based on Schulmeister 2003.[13][14]

Hymenoptera
Hymenoptera, 250mya

Xyeloidea (Triassic-present) Xyelapusilla.jpg

Tenthredinoidea Diprionpini crop.jpg

Pamphilioidea Caenolyda reticulata.jpg

Unicalcarida

Cephoidea (stem sawflies) Hartigia linearis.jpg

Siricoidea (horntails or wood wasps) Hymenoptera Vielfalt Horntail

Xiphydrioidea (wood wasps) Xiphydria prolongata crop.jpg

parasitism

Orussoidea (parasitic wood wasps) Orussus coronatus.jpg

"wasp waist" 200mya

APOCRITA (ants, bees, wasps) Specimen of Podalonia tydei (Le Guillou, 1841)

Symphyta (red bar) are paraphyletic as Apocrita are excluded.

Anatomy

Bombus muscorum1
Bombus muscorum drinking nectar with its long proboscis

Hymenopterans range in size from very small to large insects, and usually have two pairs of wings. Their mouthparts are adapted for chewing, with well-developed mandibles (ectognathous mouthparts). Many species have further developed the mouthparts into a lengthy proboscis, with which they can drink liquids, such as nectar. They have large compound eyes, and typically three simple eyes, ocelli.

The forward margin of the hind wing bears a number of hooked bristles, or "hamuli", which lock onto the fore wing, keeping them held together. The smaller species may have only two or three hamuli on each side, but the largest wasps may have a considerable number, keeping the wings gripped together especially tightly. Hymenopteran wings have relatively few veins compared with many other insects, especially in the smaller species.

In the more ancestral hymenopterans, the ovipositor is blade-like, and has evolved for slicing plant tissues. In the majority, however, it is modified for piercing, and, in some cases, is several times the length of the body. In some species, the ovipositor has become modified as a stinger, and the eggs are laid from the base of the structure, rather than from the tip, which is used only to inject venom. The sting is typically used to immobilise prey, but in some wasps and bees may be used in defense.[15]

Hymenopteran larvae typically have a distinct head region, three thoracic segments, and usually nine or 10 abdominal segments. In the suborder Symphyta, the larvae resemble caterpillars in appearance, and like them, typically feed on leaves. They have large chewing mandibles, three pairs of thoracic limbs, and, in most cases, six or eight abdominal prolegs. Unlike caterpillars, however, the prolegs have no grasping spines, and the antennae are reduced to mere stubs. Symphytan larvae that are wood borers or stem borers have no abdominal legs and the thoracic legs are smaller than those of non-borers.

With rare exceptions larvae of the suborder Apocrita have no legs and are maggotlike in form, and are adapted to life in a protected environment. This may be the body of a host organism, or a cell in a nest, where the adults will care for the larva. In parasitic forms, the head is often greatly reduced and partially withdrawn into the prothorax (anterior part of the thorax). Sense organs appear to be poorly developed, with no ocelli, very small or absent antennae, and toothlike, sicklelike, or spinelike mandibles. They are also unable to defecate until they reach adulthood due to having an incomplete digestive tract (a blind sac), presumably to avoid contaminating their environment.[15] The larvae of stinging forms (Aculeata) generally have 10 pairs of spiracles, or breathing pores, whereas parasitic forms usually have nine pairs present.[16]

Reproduction

Sex determination

Among most or all hymenopterans, sex is determined by the number of chromosomes an individual possesses.[17] Fertilized eggs get two sets of chromosomes (one from each parent's respective gametes) and develop into diploid females, while unfertilized eggs only contain one set (from the mother) and develop into haploid males. The act of fertilization is under the voluntary control of the egg-laying female, giving her control of the sex of her offspring.[15] This phenomenon is called haplodiploidy.

However, the actual genetic mechanisms of haplodiploid sex determination may be more complex than simple chromosome number. In many Hymenoptera, sex is actually determined by a single gene locus with many alleles.[17] In these species, haploids are male and diploids heterozygous at the sex locus are female, but occasionally a diploid will be homozygous at the sex locus and develop as a male, instead. This is especially likely to occur in an individual whose parents were siblings or other close relatives. Diploid males are known to be produced by inbreeding in many ant, bee, and wasp species. Diploid biparental males are usually sterile but a few species that have fertile diploid males are known.[18]

One consequence of haplodiploidy is that females on average actually have more genes in common with their sisters than they do with their own daughters. Because of this, cooperation among kindred females may be unusually advantageous, and has been hypothesized to contribute to the multiple origins of eusociality within this order.[15][19] In many colonies of bees, ants, and wasps, worker females will remove eggs laid by other workers due to increased relatedness to direct siblings, a phenomenon known as worker policing.[20]

Another consequence is that hymenopterans may be more resistant to the deleterious effects of inbreeding. As males are haploid, any recessive genes will automatically be expressed, exposing them to natural selection. Thus, the genetic load of deleterious genes is purged relatively quickly.[21]

Thelytoky

Some hymenopterans take advantage of parthenogenesis, the creation of embryos without fertilization. Thelytoky is a particular form of parthenogenesis in which female embryos are created (without fertilisation). The form of thelytoky in hymenopterans is a kind of automixis in which two haploid products (proto-eggs) from the same meiosis fuse to form a diploid zygote. This process tends to maintain heterozygosity in the passage of the genome from mother to daughter. It is found in several ant species including the desert ant Cataglyphis cursor,[22] the clonal raider ant Cerapachys biroi,[23] the predaceous ant Platythyrea punctata,[24] and the electric ant (little fire ant) Wasmannia auropunctata.[25] It also occurs in the Cape honey bee Apis mellifera capensis.[26]

Oocytes that undergo automixis with central fusion often have a reduced rate of crossover recombination, which helps to maintain heterozygosity and avoid inbreeding depression. Species that display central fusion with reduced recombination include the ants Platythyrea punctata[24] and Wasmannia auropunctata[25] and the honey bee Apis mellifera capensis.[26] In A. m. capensis, the recombination rate during meiosis is reduced more than tenfold.[26] In W. auropunctata the reduction is 45 fold.[25]

Single queen colonies of the narrow headed ant Formica exsecta illustrate the possible deleterious effects of increased homozygosity. Colonies of this species which have more homozygous queens will age more rapidly, resulting in reduced colony survival.[27]

Diet

Different species of Hymenoptera show a wide range of feeding habits. The most primitive forms are typically herbivorous, feeding on leaves or pine needles. Stinging wasps are predators, and will provision their larvae with immobilised prey, while bees feed on nectar and pollen.

A huge number of species are parasitoids as larvae. The adults inject the eggs into a host, which they begin to consume after hatching. For example, the eggs of the endangered Papilio homerus are parasitized at a rate of 77%, mainly by Hymenoptera species.[28] Some species are even hyperparasitoid, with the host itself being another parasitoid insect. Habits intermediate between those of the herbivorous and parasitoid forms are shown in some hymenopterans, which inhabit the galls or nests of other insects, stealing their food, and eventually killing and eating the occupant.[15]

Classification

Large rose sawfly (Arge pagana stephensii)
Symphyta, without a waist: the sawfly Arge pagana
AD2009Sep09 Vespula germanica 01
Apocrita, with narrow waists: the wasp Vespula germanica

The Hymenoptera are divided into two groups; the Symphyta which have no waist, and the Apocrita which have a narrow waist.[29]

Symphyta

The suborder Symphyta includes the sawflies, horntails, and parasitic wood wasps. The group may be paraphyletic, as it has been suggested that the family Orussidae may be the group from which the Apocrita arose. They have an unconstricted junction between the thorax and abdomen. The larvae are herbivorous, free-living, and eruciform, with three pairs of true legs, prolegs (on every segment, unlike Lepidoptera) and ocelli. The prolegs do not have crochet hooks at the ends unlike the larvae of the Lepidoptera.[29]

Apocrita

The wasps, bees, and ants together make up the suborder (and clade) Apocrita, characterized by a constriction between the first and second abdominal segments called a wasp-waist (petiole), also involving the fusion of the first abdominal segment to the thorax. Also, the larvae of all Apocrita lack legs, prolegs, or ocelli. The hindgut of the larvae also remains closed during development, with feces being stored inside the body, with the exception of some bee larvae where the larval anus has reappeared through developmental reversion. In general, the anus only opens at the completion of larval growth.[29]

See also

References

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  2. ^ Mayhew, Peter J. (2007). "Why are there so many insect species? Perspectives from fossils and phylogenies". Biological Reviews. 82 (3): 425–454. doi:10.1111/j.1469-185X.2007.00018.x. PMID 17624962.
  3. ^ Janke, Axel; Klopfstein, Seraina; Vilhelmsen, Lars; Heraty, John M.; Sharkey, Michael; Ronquist, Fredrik (2013). "The Hymenopteran Tree of Life: Evidence from Protein-Coding Genes and Objectively Aligned Ribosomal Data". PLoS ONE. 8 (8): e69344. Bibcode:2013PLoSO...869344K. doi:10.1371/journal.pone.0069344. PMC 3732274. PMID 23936325.
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  14. ^ Schulmeister, S. "Symphyta". Retrieved 28 November 2016.
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  27. ^ Haag-Liautard C, Vitikainen E, Keller L, Sundström L (2009). "Fitness and the level of homozygosity in a social insect". J. Evol. Biol. 22 (1): 134–142. doi:10.1111/j.1420-9101.2008.01635.x. PMID 19127611.
  28. ^ Lehnert, Matthew S.; Kramer, Valerie R.; Rawlins, John E.; Verdecia, Vanessa; Daniels, Jaret C. (2017-07-10). "Jamaica's Critically Endangered Butterfly: A Review of the Biology and Conservation Status of the Homerus Swallowtail (Papilio (Pterourus) homerus Fabricius)". Insects. 8 (3): 68. doi:10.3390/insects8030068. PMC 5620688. PMID 28698508.
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Bibliography

External links

General
Systematics
Regional Lists
Books
Ant

Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the Cretaceous period, about 140 million years ago, and diversified after the rise of flowering plants. More than 12,500 of an estimated total of 22,000 species have been classified. They are easily identified by their elbowed antennae and the distinctive node-like structure that forms their slender waists.

Ants form colonies that range in size from a few dozen predatory individuals living in small natural cavities to highly organised colonies that may occupy large territories and consist of millions of individuals. Larger colonies consist of various castes of sterile, wingless females, most of which are workers (ergates), as well as soldiers (dinergates) and other specialised groups. Nearly all ant colonies also have some fertile males called "drones" (aner) and one or more fertile females called "queens" (gynes). The colonies are described as superorganisms because the ants appear to operate as a unified entity, collectively working together to support the colony.

Ants have colonised almost every landmass on Earth. The only places lacking indigenous ants are Antarctica and a few remote or inhospitable islands. Ants thrive in most ecosystems and may form 15–25% of the terrestrial animal biomass. Their success in so many environments has been attributed to their social organisation and their ability to modify habitats, tap resources, and defend themselves. Their long co-evolution with other species has led to mimetic, commensal, parasitic, and mutualistic relationships.Ant societies have division of labour, communication between individuals, and an ability to solve complex problems. These parallels with human societies have long been an inspiration and subject of study. Many human cultures make use of ants in cuisine, medication, and rituals. Some species are valued in their role as biological pest control agents. Their ability to exploit resources may bring ants into conflict with humans, however, as they can damage crops and invade buildings. Some species, such as the red imported fire ant (Solenopsis invicta), are regarded as invasive species, establishing themselves in areas where they have been introduced accidentally.

Apoidea

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 Crabronidae, so that grouping is paraphyletic, and has led to a reclassification to produce monophyletic families.

Braconidae

The Braconidae are a family of parasitoid wasps. After the closely related Ichneumonidae, braconids make up the second-largest family in the order Hymenoptera, with about 17,000 recognized species and many thousands more undescribed. One analysis estimated a total between 30,000 and 50,000, and another provided a narrower estimate between 42,000 and 43,000 species.

Chalcid wasp

Chalcid wasps (, from Greek khalkos, meaning 'copper', for their metallic colour) are insects within the superfamily Chalcidoidea, part of the order Hymenoptera. The superfamily contains some 22,500 known species, and an estimated total diversity of more than 500,000 species, meaning the vast majority have yet to be discovered and described. The name "chalcid" is often confused with the name "chalcidid", though the latter refers strictly to one constituent family, the Chalcididae, rather than the superfamily as a whole; accordingly, most recent publications (e.g.,) use the name "chalcidoid" when referring to members of the superfamily.

Most of the species are parasitoids of other insects, attacking the egg or larval stage of their host, though many other life cycles are known. These hosts are to be found in at least 12 different insect orders including Lepidoptera (butterflies and moths), Diptera (true flies), Coleoptera (beetles), Hemiptera (true bugs), and other Hymenoptera, as well as two orders of Arachnida, and even one family of nematodes. For example, the chalcid fly is responsible for a small percentage of egg death in the wood white butterfly (L. sinapis). When the host is itself a parasitoid, they are referred to as hyperparasitoids. A small percentage are phytophagous and the larvae feed inside seeds, stems, and galls, including some that act as pollinators (e.g. fig wasps). Generally beneficial to humans as a group, chalcidoids help keep various crop pests under control, and many species have been imported as biocontrol agents. Moth parasitoid Copidosoma floridanum is one such species, whose genome is being sequenced by the Human Genome Sequencing Center as part of the i5K project, which aims to sequence the genomes of 5,000 arthropods.

Chalcidoids are tiny, dark-coloured wasps, typically black or brown, but often metallic blue or green, with complex sculpturing on the body. They are also recognized by the characteristic reduced wing venation, similar to that seen in other superfamilies of parasitoid wasps.

Charles Thomas Bingham

Charles Thomas Bingham (16 April 1848, India – 18 October 1908 West Kensington, London) was an Irish military officer and entomologist.Bingham was born in India of an old Irish family, and he was educated in Ireland. His military career began in India where he was a soldier in the Bombay Staff Corps and later with the Bengal Staff Corps. At first interested in ornithology he took up entomology from 1877 following a posting to Burma where he was also conservator of forests.

On his retirement in 1894 he settled with his wife and two sons (his three daughters married in India) in London. Here he worked, unpaid, in the Insect Room of the Natural History Museum, organising and cataloguing the world collection of aculeate Hymenoptera. He took over from William Thomas Blanford the editorship of two of the Hymenoptera volumes of The Fauna of British India, Including Ceylon and Burma series and two of the butterfly volumes.

He was elected a fellow of the Entomological Society of London in 1895 and was a member of its council from 1903 to 1906. In the same year he became a fellow of the Zoological Society of London.

Endopterygota

Endopterygota (from Ancient Greek endon “inner” + pterón, “wing” + New Latin -ota “having”), also known as Holometabola, is a superorder of insects within the infraclass Neoptera that go through distinctive larval, pupal, and adult stages. They undergo a radical metamorphosis, with the larval and adult stages differing considerably in their structure and behaviour. This is called holometabolism, or complete metamorphism.

The Endopterygota are among the most diverse insect superorders, with over 1 million living species divided between 11 orders, containing insects such as butterflies, flies, fleas, bees, ants, and beetles.They are distinguished from the Exopterygota (or Hemipterodea) by the way in which their wings develop. Endopterygota (meaning literally "internal winged forms") develop wings inside the body and undergo an elaborate metamorphosis involving a pupal stage. Exopterygota ("external winged forms") develop wings on the outside their bodies and do not go through a pupal stage. The latter trait is plesiomorphic, however, and not exclusively found in the exopterygotes, but also in groups such as Odonata (dragonflies and damselflies), which are not Neoptera, but more basal among insects.

The earliest endopterygote fossils date from the Carboniferous.

Ichneumonidae

The Ichneumonidae are a parasitoid wasp family within the order Hymenoptera. Unlike other parasites, parasitoids kill their hosts. Ichneumonids are important parasitoids of other invertebrates; common hosts are larvae and pupae of Coleoptera (beetles), Hymenoptera (wasps and relatives), and Lepidoptera (moths and butterflies). About 25,000 species have been described worldwide. Estimates of the total species range from 60,000 to over 100,000 – more than any other hymenopteran family.

The most commonly recognized wasps are boldly colored social wasps whose females have venomous stings, such as in North America are called yellowjackets. They are in a separate clade: Aculeata. In contrast, ichneumonids have ovipositors instead of stingers, and they are all solitary. They use their ovipositors to lay eggs on or in the body of their prey, and the eggs hatch into carnivorous larvae that eat and kill the host.

The distribution of the ichneumonids was traditionally considered an exception to the common latitudinal gradient in species diversity, since the family was thought to be at its most species-rich in the temperate zone instead of the tropics, but numerous new tropical species have now been discovered.

Ichneumonoidea

The superfamily Ichneumonoidea contains the two largest families within Hymenoptera: Ichneumonidae and Braconidae. The group is thought to contain as many as 100,000 species, many of which have not yet been described. Like other parasitoid wasps, they were long placed in the "Parasitica", variously considered as an infraorder or an unranked clade, now known to be paraphyletic.

Instar

An instar ( (listen), from the Latin "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (ecdysis), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, changes in the number of body segments or head width. After moulting, i.e. shedding their exoskeleton, the juvenile arthropods continue in their life cycle until they either pupate or moult again. The instar period of growth is fixed; however, in some insects, like the salvinia stem-borer moth, the number of instars depends on early larval nutrition. Some arthropods can continue to moult after sexual maturity, but the stages between these subsequent moults are generally not called instars.

For most insect species, an instar is the developmental stage of the larval forms of holometabolous (complete metamorphism) or nymphal forms of hemimetabolous (incomplete metamorphism) insects, but an instar can be any developmental stage including pupa or imago (the adult, which does not moult in insects).

The number of instars an insect undergoes often depends on the species and the environmental conditions, as described for a number of species of Lepidoptera. However it is believed that the number of instars can be physiologically constant per species in some insect orders, as for example Diptera and Hymenoptera. It should be minded that the number of larval instars is not directly related to speed of development. For instance, environmental conditions may dramatically affect the developmental rates of species and still have no impact on the number of larval instars. As examples, lower temperatures and lower humidity often slow the rate of development- an example is seen in the lepidopteran tobacco budworm and that may have an effect on how many molts will caterpillars undergo. On the other hand, temperature is demonstrated to affect the development rates of a number of hymenopterans without affecting numbers of instars or larval morphology, as observed in the ensign wasp and in the red imported fire ant. In fact the number of larval instars in ants has been the subject of a number of recent investigations, and no instances of temperature-related variation in numbers of instars have yet been recorded.

Megachile

The genus Megachile is a cosmopolitan group of solitary bees, often called leafcutter bees or leafcutting bees; it also includes the called resin bees and mortar bees. While other genera within the family Megachilidae may chew leaves or petals into fragments to build their nests, certain species within Megachile neatly cut pieces of leaves or petals, hence their common name. This is one of the largest genera of bees, with more than 1500 species in over 50 subgenera. North America has many native Megachile species. The introduced alfalfa leafcutter bee (Megachile rotundata) is managed for crop pollination.

Parasitoid

A parasitoid is an organism that lives in close association with its host and at the host's expense, and which sooner or later kills it. Parasitoidism is one of six major evolutionary strategies within parasitism, distinguished by the fatal prognosis for the host, which makes the strategy close to predation.

Among parasitoids, strategies range from living inside the host, allowing it to go on growing until the parasitoid emerges as an adult, to paralysing the host and living outside it. Hosts include other parasitoids, resulting in hyperparasitism; in the case of oak galls, up to five levels of parasitism are possible. Some parasitoids influence their host's behaviour in ways that favour the propagation of the parasitoid.

Parasitoids are found in a variety of taxa across the endopterygote insects, whose complete metamorphosis may have pre-adapted them for a split lifestyle, with parasitoid larvae and freeliving adults. Most are in the Hymenoptera, where the ichneumons and many other parasitoid wasps are highly specialised for a parasitoidal way of life. Other parasitoids are in the Diptera, Coleoptera and other orders of endopterygote insects. Some of these, usually but not only wasps, are used in biological pest control.

The biology of parasitoidism has inspired science fiction authors and scriptwriters to create numerous parasitoidal aliens that kill their human hosts, such as the alien species in Ridley Scott's 1979 film Alien.

Parasitoid wasp

Parasitoid wasps are a large group of hymenopteran superfamilies, with all but the wood wasps (Orussoidea) being in the wasp-waisted Apocrita. As parasitoids, they lay their eggs on or in the bodies of other arthropods, sooner or later causing the death of these hosts. Different species specialise in hosts from different insect orders, most often Lepidoptera, though some select beetles, flies, or bugs; the spider wasps (Pompilidae) exclusively attack spiders.

Parasitoid wasp species differ in which host life-stage they attack: eggs, larvae, pupae, or adults. They mainly follow one of two major strategies within parasitism: either they are endoparasitic, developing inside the host, and koinobiont, allowing the host to continue to feed, develop, and moult; or they are ectoparasitic, developing outside the host, and idiobiont, paralysing the host immediately. Some endoparasitic wasps of the superfamily Ichneumonoidea have a mutualistic relationship with polydnaviruses, the viruses suppressing the host's immune defenses.Parasitoidism evolved only once in the Hymenoptera, during the Permian, leading to a single clade, but the parasitic lifestyle has secondarily been lost several times including among the ants, bees, and yellowjacket wasps. As a result, the order Hymenoptera contains many families of parasitoids, intermixed with non-parasitoid groups. The parasitoid wasps include some very large groups, some estimates giving the Chalcidoidea as many as 500,000 species, the Ichneumonidae 100,000 species, and the Braconidae up to 50,000 species.

Host insects have evolved a range of defences against parasitoid wasps, including hiding, wriggling, and camouflage markings.

Many parasitoid wasps are considered beneficial to humans because they naturally control agricultural pests. Some are applied commercially in biological pest control, starting in the 1920s with Encarsia formosa to control whitefly in greenhouses. Historically, parasitoidism in wasps influenced the thinking of Charles Darwin.

Pompiloidea

Pompiloidea is a superfamily of spider wasps, velvet ants, etc. in the order Hymenoptera. There are at least 5 families and 290 described species in Pompiloidea.

Potter wasp

Potter wasps (or mason wasps), the Eumeninae, are a cosmopolitan wasp group presently treated as a subfamily of Vespidae, but sometimes recognized in the past as a separate family, Eumenidae.

Royal Entomological Society Handbooks

Handbooks for the Identification of British Insects is a series of books produced by the Royal Entomological Society (RES). The aim of the Handbooks is to provide illustrated identification keys to the insects of Britain, together with concise morphological, biological and distributional information. The series also includes several Check Lists of British Insects. All books contain line drawings, with the most recent volumes including colour photographs. In recent years, new volumes in the series have been published by Field Studies Council, and benefit from association with the AIDGAP identification guides and Synopses of the British Fauna.

Sawfly

Sawflies are the insects of 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, with about 7,000 known species; in the entire suborder, there are 8,000 described species in more than 800 genera. The suborder Symphyta is paraphyletic, consisting of several basal groups within the order Hymenoptera. Symphyta includes all the species within Hymenoptera (sawflies, horntails, and woodwasps) that are not wasps or the descendants of wasps.

The primary distinction between sawflies and their relatives the Apocrita – the ants, bees, and wasps – is that the adults lack a "wasp waist", and instead have a broad connection between the abdomen and the thorax. Some sawflies are Batesian mimics of wasps and bees, and the ovipositor can be mistaken for a stinger. Sawflies vary in length, most measuring 2.5 millimetres (0.1 in) to 20 millimetres (0.8 in); the largest known sawfly measured 55 millimetres (2.2 in). The larvae are caterpillar-like, but can be distinguished by the number of prolegs and the absence of crochets in sawfly larvae. The great majority of sawflies are plant-eating, though the members of the superfamily Orussoidea are parasitic. The adults feed on pollen and nectar. Predators include birds, insects and small animals. The larvae of some species have anti-predator adaptations such as regurgitating irritating liquid and clustering together for safety in numbers. Sawflies are hosts to many parasitoids, most of which are Hymenoptera, the rest being Diptera.

Adult sawflies are short-lived, with a life expectancy of 7–9 days, though the larval stage can last from months to years, depending on the species. Parthenogenetic females, which do not need to mate to produce fertilised eggs, are common in the suborder, though many species have males. Sawflies go through a complete metamorphosis with four distinct life stages – egg, larva, pupa and adult. The female uses her ovipositor to drill into plant material (or, in the case of Orussoidea, other insects) and then lays eggs in groups called rafts or pods. After hatching, larvae feed on plants, often in groups. As they approach adulthood, the larvae seek a protected spot to pupate, typically in bark or the soil. Large populations of species such as the pine sawfly can cause substantial damage to economic forestry, while others such as the iris sawfly are important pests in horticulture. Outbreaks of sawfly larvae can defoliate trees and may cause dieback, stunting or death. Sawflies can be controlled through the use of insecticides, natural predators and parasites, or mechanical methods.

Sawflies first appeared 250 million years ago in the Triassic. The oldest superfamily, the Xyeloidea, has existed into the present. Over 200 million years ago, a lineage of sawflies evolved a parasitoid lifestyle, with carnivorous larvae that ate the eggs or larvae of other insects. One branch of this lineage is Apocrita, and the other is Orussidae, the parasitic wood wasps. Sawflies are distributed globally, though they are more diverse in the northern hemisphere.

Schmidt sting pain index

The Schmidt sting pain index is a pain scale rating the relative pain caused by different hymenopteran stings. It is mainly the work of Justin O. Schmidt (born 1947), an entomologist at the Carl Hayden Bee Research Center in Arizona. Schmidt has published a number of papers on the subject, and claims to have been stung by the majority of stinging Hymenoptera.

His original paper in 1983 was a way to systematize and compare the hemolytic properties of insect venoms. The index contained in the paper started from 0 for stings that are completely ineffective against humans, progressed through 2, a familiar pain such as a common bee or wasp sting and finished at 4 for the most painful stings. Synoeca septentrionalis, along with other wasps in the genus Synoeca, bullet ants and tarantula hawks were the only species to attain this ranking. In the conclusion, some descriptions of the most painful examples were given, e.g.: "Paraponera clavata stings induced immediate, excruciating pain and numbness to pencil-point pressure, as well as trembling in the form of a totally uncontrollable urge to shake the affected part."

Subsequently, Schmidt has refined his scale, culminating in a paper published in 1990, which classifies the stings of 78 species and 41 genera of Hymenoptera. Schmidt described some of the experiences in vivid detail.An entry in The Straight Dope reported that "implausibly exact numbers" which do not appear in any of Schmidt’s published scientific papers were "wheedled out of him" by Outside magazine for an article it published in 1996.In September 2015, Schmidt was co-awarded the Ig Nobel Physiology and Entomology prize with Michael Smith, for their Hymenoptera research.

Tenthredinoidea

The Tenthredinoidea are the dominant superfamily of sawflies within the Symphyta, containing some 7000 species worldwide, primarily in the family Tenthredinidae. All known larvae are phytophagous, and a number are considered pests.

The included extant families share the distinctive features of a medially narrowed pronotum, paired protibial spurs, and the loss of the transverse mesonotal groove. The superfamily also includes two extinct families. Meicai and Haiyan (1998) identified 66 extant tribes and 17 subfamilies. The superfamily includes the argid sawflies (Argidae), cimbicid sawflies (Cimbicidae), the pine or conifer sawflies (Diprionidae) and the common sawflies (Tenthredinidae).

Wasp

A wasp is any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. The Apocrita have a common evolutionary ancestor and form a clade; wasps as a group do not form a clade, but are paraphyletic with respect to bees and ants.

The most commonly known wasps, such as yellowjackets and hornets, are in the family Vespidae and are eusocial, living together in a nest with an egg-laying queen and non-reproducing workers. Eusociality is favoured by the unusual haplodiploid system of sex determination in Hymenoptera, as it makes sisters exceptionally closely related to each other. However, the majority of wasp species are solitary, with each adult female living and breeding independently. Females typically have an ovipositor for laying eggs in or near a food source for the larvae, though in the Aculeata the ovipositor is often modified instead into a sting used for defense or prey capture. Wasps play many ecological roles. Some are predators or pollinators, whether to feed themselves or to provision their nests. Many, notably the cuckoo wasps, are kleptoparasites, laying eggs in the nests of other wasps. Many of the solitary wasps are parasitoidal, meaning they lay eggs on or in other insects (any life stage from egg to adult) and often provision their own nests with such hosts. Unlike true parasites, the wasp larvae eventually kill their hosts. Solitary wasps parasitize almost every pest insect, making wasps valuable in horticulture for biological pest control of species such as whitefly in tomatoes and other crops.

Wasps first appeared in the fossil record in the Jurassic, and diversified into many surviving superfamilies by the Cretaceous. They are a successful and diverse group of insects with tens of thousands of described species; wasps have spread to all parts of the world except for the polar regions. The largest social wasp is the Asian giant hornet, at up to 5 centimetres (2.0 in) in length; among the largest solitary wasps is a group of species known as tarantula hawks, along with the giant scoliid of Indonesia (Megascolia procer). The smallest wasps are solitary chalcid wasps in the family Mymaridae, including the world's smallest known insect, with a body length of only 0.139 mm (0.0055 in), and the smallest known flying insect, only 0.15 mm (0.0059 in) long.

Wasps have appeared in literature from Classical times, as the eponymous chorus of old men in Aristophanes' 422 BC comedy Σφῆκες (Sphēkes), The Wasps, and in science fiction from H. G. Wells's 1904 novel The Food of the Gods and How It Came to Earth, featuring giant wasps with three-inch-long stings. The name "Wasp" has been used for many warships and other military equipment.

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