sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. The wasps do not constitute a clade, a complete natural group with a single ancestor, as bees and ants are deeply nested within the wasps, having evolved from wasp ancestors. Wasps that are members of the clade Aculeata can sting
paraphyletic grouping of hundreds of thousands of species, consisting of the narrow-waisted cladeApocrita without the ants and bees. The Hymenoptera also contain the somewhat wasplike but unwaisted Symphyta
, the sawflies.
The term wasp is sometimes used more narrowly for members of the
Wasps are a diverse group, estimated at well over a hundred thousand
Chalcidoidea) that has co-evolved with it and pollinates it.
Many wasp species are parasitoids; the females deposit eggs on or in a host arthropod on which the larvae then feed. Some larvae start off as parasitoids, but convert at a later stage to consuming the plant tissues that their host is feeding on. In other species, the eggs are laid directly into plant tissues and form galls, which protect the developing larvae from predators, but not necessarily from other parasitic wasps. In some species, the larvae are predatory themselves; the wasp eggs are deposited in clusters of eggs laid by other insects, and these are then consumed by the developing wasp larvae.
The largest social wasp is the
Kikiki huna with a body length of only 158 micrometres, the smallest known flying insect.
There are estimated to be 100,000 species of
haemolymph, but if a parasitoid emerges from the host, the hyperparasites continue their life cycle inside the parasitoid. Parasitoids maintain their extreme diversity through narrow specialism. In Peru, 18 wasp species were found living on 14 fly species in only two species of Gurania climbing squash.
Of the dozens of extant wasp families, only the family
warning coloration, often in black and yellow, social wasps are frequent models for Batesian mimicry by non-stinging insects, and are themselves involved in mutually beneficial Müllerian mimicry of other distasteful insects including bees and other wasps. All species of social wasps construct their nests using some form of plant fiber (mostly wood pulp) as the primary material, though this can be supplemented with mud, plant secretions (e.g., resin), and secretions from the wasps themselves; multiple fibrous brood cells are constructed, arranged in a honeycombed pattern, and often surrounded by a larger protective envelope. Wood fibres are gathered from weathered wood, softened by chewing and mixing with saliva. The placement of nests varies from group to group; yellow jackets such as Dolichovespula media and D. sylvestris prefer to nest in trees and shrubs; Protopolybia exiguaattaches its nests on the underside of leaves and branches; Polistes erythrocephalus chooses sites close to a water source.
Other wasps, like Agelaia multipicta and Vespula germanica, like to nest in cavities that include holes in the ground, spaces under homes, wall cavities or in lofts. While most species of wasps have nests with multiple combs, some species, such as Apoica flavissima, only have one comb. The length of the reproductive cycle depends on latitude; Polistes erythrocephalus, for example, has a much longer (up to 3 months longer) cycle in temperate regions.
building mud nest, France. The latest ring of mud is still wet.
The vast majority of wasp species are solitary insects. Having mated, the adult female forages alone and if it builds a nest, does so for the benefit of its own offspring. Some solitary wasps nest in small groups alongside others of their species, but each is involved in caring for its own offspring (except for such actions as stealing other wasps’ prey or laying in other wasp's nests). There are some species of solitary wasp that build communal nests, each insect having its own cell and providing food for its own offspring, but these wasps do not adopt the division of labour and the complex behavioural patterns adopted by eusocial species.
Adult solitary wasps spend most of their time in preparing their nests and foraging for food for their young, mostly insects or spiders. Their nesting habits are more diverse than those of social wasps. Many species dig burrows in the ground.Mud daubers and pollen wasps construct mud cells in sheltered places.Potter wasps similarly build vase-like nests from mud, often with multiple cells, attached to the twigs of trees or against walls.
Predatory wasp species normally subdue their prey by stinging it, and then either lay their eggs on it, leaving it in place, or carry it back to their nest where an egg may be laid on the prey item and the nest sealed, or several smaller prey items may be deposited to feed a single developing larva. Apart from providing food for their offspring, no further maternal care is given. Members of the family Chrysididae, the cuckoo wasps, are kleptoparasites and lay their eggs in the nests of unrelated host species.
Like all insects, wasps have a hard exoskeleton which protects their three main body parts, the head, the mesosoma (including the thorax and the first segment of the abdomen) and the metasoma. There is a narrow waist, the petiole, joining the first and second segments of the abdomen. The two pairs of membranous wings are held together by small hooks and the forewings are larger than the hind ones; in some species, the females have no wings. In females there is usually a rigid ovipositor which may be modified for injecting venom, piercing or sawing. It either extends freely or can be retracted, and may be developed into a stinger for both defence and for paralysing prey.
In addition to their large
ocelli, which are typically arranged in a triangle just forward of the vertex of the head. Wasps possess mandibles adapted for biting and cutting, like those of many other insects, such as grasshoppers, but their other mouthparts are formed into a suctorial proboscis, which enables them to drink nectar.
The larvae of wasps resemble maggots, and are adapted for life in a protected environment; this may be the body of a host organism or a cell in a nest, where the larva either eats the provisions left for it or, in social species, is fed by the adults. Such larvae have soft bodies with no limbs, and have a blind gut (presumably so that they do not foul their cell).
) feeding on a fly after paralysing it with its sting
Adult solitary wasps mainly feed on nectar, but the majority of their time is taken up by foraging for food for their carnivorous young, mostly insects or spiders. Apart from providing food for their larval offspring, no maternal care is given. Some wasp species provide food for the young repeatedly during their development (progressive provisioning). Others, such as potter wasps (Eumeninae) and sand wasps (Ammophila, Sphecidae), repeatedly build nests which they stock with a supply of immobilised prey such as one large caterpillar, laying a single egg in or on its body, and then sealing up the entrance (mass provisioning).
Predatory and parasitoidal wasps subdue their prey by stinging it. They hunt a wide variety of prey, mainly other insects (including other Hymenoptera), both larvae and adults.
Pompilidae specialize in catching spiders to provision their nests.
Some social wasps are omnivorous, feeding on fallen fruit, nectar, and carrion such as dead insects. Adult male wasps sometimes visit flowers to obtain nectar. Some wasps, such as Polistes fuscatus, commonly return to locations where they previously found prey to forage. In many social species, the larvae exude copious amounts of salivary secretions that are avidly consumed by the adults. These include both sugars and amino acids, and may provide essential protein-building nutrients that are otherwise unavailable to the adults (who cannot digest proteins).
Females of the solitary wasp parasitoid Venturia canescens can avoid mating with their brothers through kin recognition. In experimental comparisons, the probability that a female will mate with an unrelated male was about twice as high as the chance of her mating with brothers. Female wasps appear to recognize siblings on the basis of a chemical signature carried or emitted by males. Sibling-mating avoidance reduces inbreeding depression that is largely due to the expression of homozygous deleterious recessive mutations.
While the vast majority of wasps play no role in pollination, a few species can effectively transport pollen and pollinate several plant species. Since wasps generally do not have a fur-like covering of soft hairs and a special body part for pollen storage (pollen basket) as some bees do, pollen does not stick to them well. However it has been shown that even without hairs, several wasp species are able to effectively transport pollen, therefore contributing for potential pollination of several plant species.
The Agaonidae (fig wasps) are the only pollinators of nearly 1000 species of figs, and thus are crucial to the survival of their host plants. Since the wasps are equally dependent on their fig trees for survival, the coevolved relationship is fully mutualistic.
Most solitary wasps are parasitoids. As adults, those that do feed typically only take nectar from flowers. Parasitoid wasps are extremely diverse in habits, many laying their eggs in inert stages of their host (egg or pupa), sometimes paralysing their prey by injecting it with venom through their ovipositor. They then insert one or more eggs into the host or deposit them upon the outside of the host. The host remains alive until the parasitoid larvae pupate or emerge as adults.
The Ichneumonidae are specialized parasitoids, often of Lepidoptera larvae deeply buried in plant tissues, which may be woody. For this purpose, they have exceptionally long ovipositors; they detect their hosts by smell and vibration. Some of the largest species, including Rhyssa persuasoria and Megarhyssa macrurus, parasitise horntails, large sawflies whose adult females also have impressively long ovipositors. Some parasitic species have a mutualistic relationship with a polydnavirus that weakens the host's immune system and replicates in the oviduct of the female wasp.
Many wasp lineages, including those in the families
Pompilidae, attack and sting prey items that they use as food for their larvae; while Vespidae usually macerate their prey and feed the resulting bits directly to their brood, most predatory wasps paralyze their prey and lay eggs directly upon the bodies, and the wasp larvae consume them. Apart from collecting prey items to provision their young, many wasps are also opportunistic feeders, and will suck the body fluids of their prey. Although vespid mandibles are adapted for chewing and they appear to be feeding on the organism, they are often merely macerating it into submission. The impact of the predation of wasps on economic pests is difficult to establish.
The roughly 140 species of beewolf (Philanthinae) hunt bees, including honeybees, to provision their nests; the adults feed on nectar and pollen.
Social wasps are considered pests when they become excessively common, or nest close to buildings. People are most often stung in late summer and early autumn, when wasp colonies stop breeding new workers; the existing workers search for sugary foods and are more likely to come into contact with humans.
Some species of parasitic wasp, especially in groups such as
aubergine (eggplant), flowers such as marigold, and strawberry. Several species of parasitic wasp are natural predators of aphids and can help to control them. For instance, Aphidius matricariae is used to control the peach-potato aphid.
of tomato and other horticultural crops.
Tomato leaf covered with nymphs of whitefly parasitised by Encarsia formosa
Wasps RFC is an English professional rugby union team originally based in London but now playing in Coventry; the name dates from 1867 at a time when names of insects were fashionable for clubs. The club's first kit is black with yellow stripes. The club has an amateur side called Wasps FC.
Wasps have been modelled in jewellery since at least the nineteenth century, when diamond and emerald wasp brooches were made in gold and silver settings. A fashion for wasp waisted female silhouettes with sharply cinched waistlines emphasizing the wearer's hips and bust arose repeatedly in the nineteenth and twentieth centuries.
The Ancient Greek playwright Aristophanes wrote the comedy play Σφῆκες (Sphēkes), The Wasps, first put on in 422 BC. The "wasps" are the chorus of old jurors.
It flew, he is convinced, within a yard of him, struck the ground, rose again, came down again perhaps thirty yards away, and rolled over with its body wriggling and its sting stabbing out and back in its last agony. He emptied
both barrels into it before he ventured to go near. When he came to measure the thing, he found it was twenty-seven and a half inches across its open wings, and its sting was three inches long. ... The day after, a cyclist riding, feet up, down the hill between Sevenoaks and Tonbridge, very narrowly missed running over a second of these giants that was crawling across the roadway.
Botticelli's Venus and Mars, 1485, with a wasp's nest on right, probably a symbol of the Vespucci family (Italian vespa, wasp) who commissioned the painting.
Parasitoidal wasps played an indirect role in the nineteenth-century evolution debate. The Ichneumonidae contributed to Charles Darwin's doubts about the nature and existence of a well-meaning and all-powerful Creator. In an 1860 letter to the American naturalist Asa Gray, Darwin wrote:
I own that I cannot see as plainly as others do, and as I should wish to do, evidence of design and beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars, or that a cat should play with mice.
With its powerful sting and familiar appearance, the wasp has given its name to many ships, aircraft and military vehicles. Nine ships and one shore establishment of the Royal Navy have been named HMS Wasp, the first an 8-gun sloop launched in 1749.
Eleven ships of the
^Methods to estimate species diversity include extrapolating the rate of species descriptions by subfamily (as in the Braconidae) until zero is reached; and extrapolating geographically from the species distribution of well-studied taxa to the group of interest (say, the Braconidae). Dolphin et al found a correlation between the predicted numbers of undescribed species by these two methods, doubling or tripling the number of species in the group.