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Hornets (insects in the genus ''Vespa'') are the largest of the
eusocial Eusociality (from Greek εὖ ''eu'' "good" and social), the highest level of organization of sociality, is defined by the following characteristics: cooperative brood care (including care of offspring from other individuals), overlapping gen ...
wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. ...
s, and are similar in appearance to their close relatives
yellowjacket Yellowjacket or yellowjacket is the common name in North America for predatory social wasps of the genus, genera ''Vespula'' and ''Dolichovespula''. Members of these genera are known simply as "wasps" in other English-speaking countries. Most of ...
s. Some species can reach up to in length. They are distinguished from other vespine wasps by the relatively large top margin of the head. Worldwide, 22 species of ''Vespa'' are recognized.A.H. Smith-Pardo, J.M. Carpenter, L. Kimsey (2020) The diversity of hornets in the genus ''Vespa'' (Hymenoptera: Vespidae; Vespinae), their importance and interceptions in the United States. Insect Systematics and Diversity 4(3) https://doi.org/10.1093/isd/ixaa006 Most species only occur in the tropics of Asia, though the European hornet (''V. crabro''), is widely distributed throughout Europe, Russia, North America, and north-eastern Asia. Wasps native to North America in the genus '' Dolichovespula'' are commonly referred to as hornets (e.g., baldfaced hornets), but are actually
yellowjacket Yellowjacket or yellowjacket is the common name in North America for predatory social wasps of the genus, genera ''Vespula'' and ''Dolichovespula''. Members of these genera are known simply as "wasps" in other English-speaking countries. Most of ...
s. Like other social wasps, hornets build communal nests by chewing wood to make a papery pulp. Each nest has one queen, which lays eggs and is attended by workers that, while genetically female, cannot lay fertile eggs. Most species make exposed nests in trees and shrubs, but some (such as '' Vespa orientalis'') build their nests underground or in other cavities. In the tropics, these nests may last year-round, but in temperate areas, the nest dies over the winter, with lone queens hibernating in leaf litter or other insulative material until the spring. Male hornets are docile and do not have stingers. Hornets are often considered pests, as they aggressively guard their nesting sites when threatened and their stings can be more dangerous than those of bees.


Classification

While taxonomically well defined, some confusion may remain about the differences between hornets and other wasps of the family
Vespidae The Vespidae are a large (nearly 5000 species), diverse, cosmopolitan family of wasps, including nearly all the known eusocial wasps (such as ''Polistes fuscatus'', ''Vespa orientalis'', and ''Vespula germanica'') and many solitary wasps. Each ...
, specifically the yellowjackets, which are members of the same subfamily. Also, a related genus of Asian nocturnal vespines, '' Provespa'', is referred to as "night wasps" or "night hornets", though they are not true hornets. Some other large wasps are sometimes referred to as hornets, most notably the bald-faced hornet (''Dolichovespula maculata'') found in North America. It is set apart by its black and ivory coloration. The name "hornet" is used for this species primarily because of its habit of making aerial nests (similar to some of the true hornets) rather than subterranean nests. Another example is the Australian hornet (''Abispa ephippium''), which is actually a species of
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. Recognition Most eumenine species are black or brown, ...
.


Distribution

Hornets are found mainly in the Northern Hemisphere. The common European hornet (''V. crabro'') is the best-known species, widely distributed in Europe (but is never found north of the 63rd parallel), Ukraine, and European Russia (except in extreme northern areas). In the east, the species' distribution area stretches over the
Ural Mountains The Ural Mountains ( ; rus, Ура́льские го́ры, r=Uralskiye gory, p=ʊˈralʲskʲɪjə ˈɡorɨ; ba, Урал тауҙары) or simply the Urals, are a mountain range that runs approximately from north to south through western ...
to western Siberia (found in the vicinity of
Khanty-Mansiysk Khanty-Mansiysk ( rus, Ха́нты-Манси́йск, Khánty-Mansíysk, lit. ''Khanty-Mansi Town''; Khanty: , ''Jomvoćś''; Mansi: , ''Abga'') is a city and the administrative center of Khanty-Mansi Autonomous Okrug–Yugra, Russia. It stan ...
). In Asia, the common European hornet is found in southern Siberia, as well as in eastern China. The common European hornet was accidentally introduced to eastern North America about the middle of the 19th century and has lived there since at about the same latitudes as in Europe. However, it has never been found in western North America. The
Asian giant hornet The Asian giant hornet (''Vespa mandarinia'') or northern giant hornet, including the color form referred to as the Japanese giant hornet, is the world's largest hornet. It is native to temperate and tropical East Asia, South Asia, Mainland Sout ...
(''V. mandarinia'') lives in the
Primorsky Krai Primorsky Krai (russian: Приморский край, r=Primorsky kray, p=prʲɪˈmorskʲɪj kraj), informally known as Primorye (, ), is a federal subject (a krai) of Russia, located in the Far East region of the country and is a part of t ...
,
Khabarovsky Krai Khabarovsk Krai ( rus, Хабаровский край, r=Khabarovsky kray, p=xɐˈbarəfskʲɪj kraj) is a federal subject (a krai) of Russia. It is geographically located in the Russian Far East and is a part of the Far Eastern Federal District ...
(southern part), and Jewish AO regions of Russia, and China, Korea, Taiwan, Cambodia, Laos, Vietnam,
Indochina Mainland Southeast Asia, also known as the Indochinese Peninsula or Indochina, is the continental portion of Southeast Asia. It lies east of the Indian subcontinent and south of Mainland China and is bordered by the Indian Ocean to the west an ...
, India, Nepal, Sri Lanka, and Thailand, but is most commonly found in the mountains of Japan, where they are commonly known as the giant sparrow bee. The Oriental hornet (''V. orientalis'') occurs in semidry, subtropical areas of central Asia (
Armenia Armenia (), , group=pron officially the Republic of Armenia,, is a landlocked country in the Armenian Highlands of Western Asia.The UNbr>classification of world regions places Armenia in Western Asia; the CIA World Factbook , , and ' ...
, Dagestan in Russia, Iran, Afghanistan, Oman, Pakistan, Turkmenistan, Uzbekistan, Tajikistan, Kyrghyzstan, southern Kazakhstan), and southern Europe (Italy, Malta, Albania, Romania, Turkey, Greece, Bulgaria, Cyprus). The
Asian hornet The Asian hornet (''Vespa velutina''), also known as the yellow-legged hornet or Asian predatory wasp, is a species of hornet indigenous to Southeast Asia. It is of concern as an invasive species in some other countries. Appearance ''Vespa velu ...
(''V. velutina'') has been introduced to France, Spain, Portugal, and Italy.


Stings

Hornets have
stinger A stinger (or sting) is a sharp organ found in various animals (typically insects and other arthropods) capable of injecting venom, usually by piercing the epidermis of another animal. An insect sting is complicated by its introduction of ve ...
s used to kill prey and defend nests. Hornet stings are more painful to humans than typical wasp stings because hornet venom contains a large amount (5%) of acetylcholine. Individual hornets can sting repeatedly; unlike
honey bee A honey bee (also spelled honeybee) is a eusocial flying insect within the genus ''Apis'' of the bee clade, all native to Afro-Eurasia. After bees spread naturally throughout Africa and Eurasia, humans became responsible for the current cosm ...
s, hornets do not die after stinging because their stingers are very finely barbed (only visible under high magnification) and can easily be withdrawn, so are not pulled out of their bodies when disengaging. The toxicity of hornet stings varies according to hornet species; some deliver just a typical insect sting, while others are among the most venomous known insects. Single hornet stings are not in themselves fatal, except sometimes to allergic victims. Multiple stings by hornets (other than ''V. crabro'') may be fatal because of highly toxic species-specific components of their venom. The stings of the
Asian giant hornet The Asian giant hornet (''Vespa mandarinia'') or northern giant hornet, including the color form referred to as the Japanese giant hornet, is the world's largest hornet. It is native to temperate and tropical East Asia, South Asia, Mainland Sout ...
(''V. mandarinia'') are among the most venomous known, and are thought to cause 30–50 human deaths annually in Japan. Between July and September 2013, hornet stings caused the death of 42 people in China. Asian giant hornet's venom can cause allergic reactions and multiple organ failure leading to death, though dialysis can be used to remove the toxins from the bloodstream. People who are allergic to wasp venom may also be allergic to hornet stings. Allergic reactions are commonly treated with epinephrine (adrenaline) injection using a device such as an
epinephrine autoinjector An epinephrine autoinjector (or adrenaline autoinjector, also known by the trademark EpiPen) is a medical device for injecting a measured dose or doses of epinephrine (adrenaline) by means of autoinjector technology. It is most often used for t ...
, with prompt follow-up treatment in a hospital. In severe cases, allergic individuals may go into anaphylactic shock and die unless treated promptly. In general, ''Vespa'' stings induce the release of
histamine Histamine is an organic nitrogenous compound involved in local immune responses, as well as regulating physiological functions in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. Since histamine was discovered ...
due to the various
mastoparan Mastoparan is a peptide toxin from wasp venom. It has the chemical structure Ile-Asn-Leu-Lys-Ala-Leu-Ala-Ala-Leu-Ala-Lys-Lys-Ile-Leu-NH2. The net effect of mastoparan's mode of action depends on cell type, but seemingly always involves exocytosis ...
s that they contain. However ''V. orientalis''
mastoparan Mastoparan is a peptide toxin from wasp venom. It has the chemical structure Ile-Asn-Leu-Lys-Ala-Leu-Ala-Ala-Leu-Ala-Lys-Lys-Ile-Leu-NH2. The net effect of mastoparan's mode of action depends on cell type, but seemingly always involves exocytosis ...
is the interesting exception because it does not induce histamine increase in victim tissue - because it does not cause
mast cell A mast cell (also known as a mastocyte or a labrocyte) is a resident cell of connective tissue that contains many granules rich in histamine and heparin. Specifically, it is a type of granulocyte derived from the myeloid stem cell that is a par ...
degranulation - and is not
immunogenic Immunogenicity is the ability of a foreign substance, such as an antigen, to provoke an immune response in the body of a human or other animal. It may be wanted or unwanted: * Wanted immunogenicity typically relates to vaccines, where the injectio ...
.


Attack pheromone

Hornets, like many social wasps, can mobilize the entire nest to sting in defense, which is highly dangerous to humans and other animals. The attack
pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
is released in case of threat to the nest. In the case of the Asian giant hornet (''V. mandarinia''), this is also used to mobilize many workers at once when attacking colonies of their prey,
honey bee A honey bee (also spelled honeybee) is a eusocial flying insect within the genus ''Apis'' of the bee clade, all native to Afro-Eurasia. After bees spread naturally throughout Africa and Eurasia, humans became responsible for the current cosm ...
s and other ''Vespa'' species. Three biologically active chemicals,
2-pentanol 2-Pentanol (IUPAC name: pentan-2-ol; also called ''sec''-amyl alcohol) is an organic chemical compound. It is used as a solvent and an intermediate in the manufacturing of other chemicals. 2-Pentanol is a component of many mixtures of amyl alcohol ...
, 3-methyl-1-butanol, and 1-methylbutyl 3-methylbutanoate, have been identified for this species. In field tests, 2-pentanol alone triggered mild alarm and defensive behavior, but adding the other two compounds increased aggressiveness in a synergistic effect. In the European hornet (''V. crabro'') the major compound of the alarm pheromone is 2-methyl-3-butene-2-ol. If a hornet is killed near a nest, it may release pheromones that can cause the other hornets to attack. Materials that come into contact with these pheromones, such as clothes, skin, and dead prey or hornets, can also trigger an attack, as can certain food flavorings, such as banana and apple flavorings, and fragrances that contain C5 alcohols and C10
esters In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...
.


Life cycle

In '' V. crabro'', the nest is founded in spring by a fertilized female known as the queen. She generally selects sheltered places such as dark, hollow tree trunks. She first builds a series of cells (up to 50) out of chewed tree bark. The cells are arranged in horizontal layers named combs, each cell being vertical and closed at the top. An egg is then laid in each cell. After 5–8 days, the egg hatches. Over the following two weeks, the larva progresses through five stages of development. During this time, the queen feeds it a protein-rich diet of insects. Then, the larva spins a silk cap over the cell's opening, and during the next two weeks, transforms into an adult, a process called metamorphosis. The adult then eats its way through the silk cap. This first generation of workers, invariably females, now gradually undertakes all the tasks formerly carried out by the queen (
foraging Foraging is searching for wild food resources. It affects an animal's fitness because it plays an important role in an animal's ability to survive and reproduce. Foraging theory is a branch of behavioral ecology that studies the foraging behavi ...
, nest building, taking care of the
brood Brood may refer to: Nature * Brood, a collective term for offspring * Brooding, the incubation of bird eggs by their parents * Bee brood, the young of a beehive * Individual broods of North American Periodical Cicadas: ** Brood X, the largest b ...
, etc.) with the exception of egg-laying, which remains exclusive to the queen. As the colony size grows, new combs are added, and an envelope is built around the cell layers until the nest is entirely covered, with the exception of an entry hole. To be able to build cells in total darkness, they apparently use gravity to aid them. At the peak of its population, which occurs in late summer, the colony can reach a size of 700 workers. At this time, the queen starts producing the first reproductive individuals. Fertilized eggs develop into females (called "
gynes The gyne (, from Greek γυνή, "woman") is the primary reproductive female caste of social insects (especially ants, wasps, and bees of order Hymenoptera, as well as termites). Gynes are those destined to become queens, whereas female workers ...
" by entomologists), and unfertilized ones develop into males (sometimes called "drones" as with honeybee drones). Adult males do not participate in nest maintenance, foraging, or caretaking of the larvae. In early to mid-autumn, they leave the nest and mate during "
nuptial flight Nuptial flight is an important phase in the reproduction of most ant, termite, and some bee species. It is also observed in some fly species, such as '' Rhamphomyia longicauda''. During the flight, virgin queens mate with males and then land t ...
s". Other temperate species (e.g., the yellow hornet, ''V. simillima'', or the Oriental hornet, ''V. orientalis'') have similar cycles. In the case of tropical species (e.g., ''V. tropica''), life histories may well differ, and in species with both tropical and temperate distributions (such as the
Asian giant hornet The Asian giant hornet (''Vespa mandarinia'') or northern giant hornet, including the color form referred to as the Japanese giant hornet, is the world's largest hornet. It is native to temperate and tropical East Asia, South Asia, Mainland Sout ...
, ''V. mandarinia''), the cycle likely depends on latitude.


Diet and feeding

Adult hornets and their relatives (e.g., yellowjackets) feed themselves with nectar and sugar-rich plant foods. Thus, they can often be found feeding on the sap of
oak trees An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
, rotting sweet fruits, honey, and any sugar-containing foodstuffs. Hornets frequently fly into orchards to feed on overripe fruit, and tend to gnaw a hole in fruit to become totally immersed in its pulp. A person who accidentally picks fruit with a feeding hornet can be attacked by the disturbed insect. The adults also attack various insects, which they kill with stings and jaws. Due to their size and the power of their venom, hornets are able to kill large insects such as
honey bee A honey bee (also spelled honeybee) is a eusocial flying insect within the genus ''Apis'' of the bee clade, all native to Afro-Eurasia. After bees spread naturally throughout Africa and Eurasia, humans became responsible for the current cosm ...
s, grasshoppers,
locust Locusts (derived from the Vulgar Latin ''locusta'', meaning grasshopper) are various species of short-horned grasshoppers in the family Acrididae that have a swarming phase. These insects are usually solitary, but under certain circumstanc ...
s, and
katydids Insects in the family Tettigoniidae are commonly called katydids (especially in North America), or bush crickets. They have previously been known as "long-horned grasshoppers". More than 8,000 species are known. Part of the suborder Ensifera, t ...
without difficulty. The victim is fully masticated and then fed to the larvae developing in the nest, rather than consumed by the adult hornets. Given that some of their prey are considered pests, hornets may be considered beneficial under some circumstances. The larvae of hornets produce a sweet secretion containing sugars and amino acids that is consumed by the workers and queens.


Predatory strategies

Hornets' ability to prey upon honey bees is favored by a number of adaptations. ''Vespa'' have a larger body size compared to their prey, a heavy exoskeleton to resist bee attacks, and strong mandibles and venomous sting. As concerns hornet hunting strategies, it has been demonstrated that some species such as '' V. tropica'' and '' V. velutina,'' can use both visual and olfactory cues for the long-range detection of honey bee colonies. Foragers of ''V. tropica'' can readily associate color and shape with potential food sources and exhibit color generalization. ''V. velutina'' foragers visually distinguish between bee dummy bait and cotton ball dummy bait, both treated with bee odors, preferring bee dummies. Foraging hornets are also selectively attracted to honey bee colony odors, in particular honey and pollen, as well as honey bee
pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
s, which may signal a high prey density. In laboratory assays, workers of ''V. velutina'' oriented especially towards
geraniol Geraniol is a monoterpenoid and an alcohol. It is the primary component of citronella oil and is a primary component of rose oil, palmarosa oil. It is a colorless oil, although commercial samples can appear yellow. It has low solubility in w ...
, a component of the honey bee worker aggregation pheromone, that could therefore represent an honest signal for hornets. Behavioral, chemical and electrophysiological analyses have also demonstrated that '' Vespa bicolor'' is attracted to (Z)-11-eicosen-1-ol, which is major compound in the alarm pheromones of both Asian (''
Apis cerana ''Apis cerana'', the eastern honey bee, Asiatic honey bee or Asian honey bee, is a species of honey bee native to South, Southeast and East Asia. This species is the sister species of ''Apis koschevnikovi'' and both are in the same subgenus as ...
'') and European ('' Apis mellifera'') honey bees, and its antennae respond to this compound. Intriguingly, this hornet attraction to honey bee pheromone is also exploited by the orchid '' Dendrobium christyanum'', which mimics the honey bee alarm pheromone in its flowers' scent to attract hornets that visit and pollinate the flowers. It is therefore likely that bee-hunting hornets visit the non-rewarding flowers in search of prey.


Species

While a history of recognizing subspecies exists within many of the ''Vespa'' species, the most recent taxonomic revision of the genus treats all subspecific names in the genus ''Vespa'' as synonyms, effectively relegating them to no more than informal names for regional color forms. * '' Vespa affinis'' * '' Vespa analis'' * '' Vespa basalis'' * '' Vespa bellicosa'' * '' Vespa bicolor'' * †'' Vespa bilineata'' * '' Vespa binghami'' * †'' Vespa ciliata'' * †'' Vespa cordifera'' * ''
Vespa crabro The European hornet (''Vespa crabro'') is the largest eusocial wasp native to Europe. It is also the only true hornet (genus ''Vespa'') found in North America, having been introduced to the United States and Canada from Europe as early as 1840. ...
'' * †'' Vespa crabroniformis'' * †'' Vespa dasypodia'' * '' Vespa ducalis'' * '' Vespa dybowskii'' * '' Vespa fervida'' * '' Vespa fumida'' * '' Vespa luctuosa'' * '' Vespa mandarinia'' * '' Vespa mocsaryana'' * '' Vespa multimaculata'' * †'' Vespa nigra'' * ''
Vespa orientalis The Oriental hornet (''Vespa orientalis'') is a social insect species of the family Vespidae. It can be found in Southwest Asia, Northeast Africa, the island of Madagascar (but no reports have been made of its presence on the island for many year ...
'' * '' Vespa philippinensis'' * †''
Vespa picea Vespa () is an Italian luxury brand of scooters and mopeds manufactured by Piaggio. The name means wasp in Italian. The Vespa has evolved from a single model motor scooter manufactured in 1946 by Piaggio & Co. S.p.A. of Pontedera, Italy to a ...
'' * ''
Vespa simillima ''Vespa simillima'', the yellow hornet, including the color form known as the , is a common hornet Hornets (insects in the genus ''Vespa'') are the largest of the eusocial wasps, and are similar in appearance to their close relatives yello ...
'' * '' Vespa soror'' * '' Vespa tropica'' * '' Vespa velutina'' * '' Vespa vivax''


Notable species

*
Asian giant hornet The Asian giant hornet (''Vespa mandarinia'') or northern giant hornet, including the color form referred to as the Japanese giant hornet, is the world's largest hornet. It is native to temperate and tropical East Asia, South Asia, Mainland Sout ...
(''V. mandarinia'') (one of its color forms is also known as the Japanese giant hornet) *
Asian hornet The Asian hornet (''Vespa velutina''), also known as the yellow-legged hornet or Asian predatory wasp, is a species of hornet indigenous to Southeast Asia. It is of concern as an invasive species in some other countries. Appearance ''Vespa velu ...
(''V. velutina'') (also known as the yellow-legged hornet or Asian predatory wasp) * black hornet ('' V. dybowskii'') * black-bellied hornet (''V. basalis'') * black shield wasp (''V. bicolor'') * European hornet (''V. crabro'') (also known as the Old World hornet or brown hornet) * greater banded hornet (''V. tropica'') * lesser banded hornet (''V. affinis'') * Oriental hornet (''V. orientalis'') * yellow hornet (''V. simillima'') (one of its color forms is also known as the Japanese yellow hornet or Japanese hornet) * '' Vespa luctuosa'' (a species which has the most lethal wasp venom (per volume))


As food and medicine

Hornet larvae are widely accepted as food in mountainous regions in China. Hornets and their nests are treated as medicine in traditional Chinese medicine.Lu Feng Fang, Materia Metrica
/ref>


Gallery

File:Vespa basalis .jpg, Black-bellied hornet (''Vespa basalis''), Xingping File:Asian predatory wasp (Vespa velutina var. nigrithorax).jpg,
Asian hornet The Asian hornet (''Vespa velutina''), also known as the yellow-legged hornet or Asian predatory wasp, is a species of hornet indigenous to Southeast Asia. It is of concern as an invasive species in some other countries. Appearance ''Vespa velu ...
(''Vespa velutina''), Shanghai


See also

* Australian hornet * Bald-faced hornet *
Yellowjacket Yellowjacket or yellowjacket is the common name in North America for predatory social wasps of the genus, genera ''Vespula'' and ''Dolichovespula''. Members of these genera are known simply as "wasps" in other English-speaking countries. Most of ...
* Characteristics of common wasps and bees


References

* *


External links


European hornet protection site
(also available in French, German, Russian, Spanish and Swedish) *


Controlling Wasps, Hornets, and Yellowjackets








on the UF / IFAS Featured Creatures Web site * {{Authority control Vespidae Biological pest control wasps Insects used as insect pest control agents