Hornets are the largest of the eusocial wasps, and are similar in appearance to their close relatives yellowjackets. Some species can reach up to 5.5 cm (2.2 in) in length. They are distinguished from other vespine wasps by the relatively large top margin of the head and by the rounded segment of the abdomen just behind the waist. Worldwide, 22 species of Vespa are recognized. Most species only occur in the tropics of Asia, though the European hornet, is widely distributed throughout Europe, Russia, North America, and Northeast Asia. Wasps native to North America in the genus Dolichovespula are commonly referred to as hornets, but are actually yellowjackets.
Yellowjacket or yellow jacket is the common name in North America for predatory social wasps of the genera Vespula and Dolichovespula. Members of these genera are known simply as "wasps" in other English-speaking countries. Most of these are black and yellow like the eastern yellowjacket Vespula maculifrons and the aerial yellowjacket Dolichovespula arenaria; some are black and white like the bald-faced hornet, Dolichovespula maculata. Others may have the abdomen background color red instead of black. They can be identified by their distinctive markings, their occurrence only in colonies, and a characteristic, rapid, side-to-side flight pattern prior to landing. All females are capable of stinging. Yellowjackets are important predators of pest insects.
The median wasp is a species of social wasp of the family Vespidae found throughout Europe and Asia. It builds aerial paper nests often in shrubs or trees, and occasionally under the eaves of buildings. It is most common to see this wasp between May and October during its 3.3 month colony cycle. Behaviours of this wasp include nest defense, curling which is believed to function in brood incubation, and gastral vibration which is involved in larval feeding. The median wasp has a halplodiploid sex determination system that results in a high level of relatedness within the colony. This species is not usually aggressive but will sting if they feel their nest is threatened. Most foraging in the nest is done by the workers once the first ones reach adulthood. These workers forage for insects, nectar, and wood for nest construction in temperatures as low as 7 °C (45 °F). The median wasp is known to be occasionally affected by the fungus Cordyceps sphecocephala and the Cricket paralysis virus.
The European paper wasp is one of the most common and well-known species of social wasps in the genus Polistes. Its diet is more diverse than that of most Polistes species—many genera of insects versus mainly caterpillars in other Polistes—giving it superior survival ability compared to other wasp species during a shortage of resources.
The eastern yellow jacket or eastern yellowjacket is a wasp found in eastern North America. Although most of their nests are subterranean, they are often considered a pest due to their nesting in recreational areas and buildings. This yellow jacket is a social insect, living in colonies of hundreds to thousands of individuals. Along with their subfamily, Vespinae, this species demonstrates supportive parental care for offspring, separation of reproductive and sterile castes, and overlapping generations. They aggressively defend their hives from threats and are known to inflict painful stings.
Polistes annularis is a species of paper wasp found throughout the eastern half of the United States. This species of red paper wasp is known for its large size and its red-and-black coloration and is variably referred to as a ringed paper wasp or jack Spaniard wasp. It builds its nest under overhangs near bodies of water that minimize the amount of sunlight penetration. It clusters its nests together in large aggregations, and consumes nectar and other insects. Its principal predator is the ant, although birds are also known to prey on it. Unlike other wasps, P. annularis is relatively robust in winter conditions, and has also been observed to store honey in advance of hibernation. This species has also been used as a model species to demonstrate the ability to use microsatellite markers in maternity assignment of social insects.
Dolichovespula saxonica, also known as the Saxon wasp, is a common social wasp found in the palearctic region, specifically in large parts of Europe and in northern and central Asia. Although originally from continental Europe, D. saxonica has since colonised Britain, mainly in the south and east, but has been recorded as far north as East Lothian, Scotland. Most of their nests are above ground in trees and bushes, but they can also be found in buildings. Due to the proliferation of nests in urban areas and near residential homes, D. saxonica can be a pest for people. As a result, many human interventions are in place to remove Saxon nests. D. saxonica has been found to use chemical signaling in a lot of behaviours, such as alarm calls, fertility cues, and chemical trails.
The Norwegian wasp is a species of eusocial wasp. It is common in Scandinavia and can also be found in Scotland and other areas in Britain and Ireland. Often known for being a tree wasp, it nests in low branches and bushes and feeds on insects. It also obtains nectar from blueberry and snowberry flowers. Although Dolichovespula norwegica were rarely considered as pests in the past, a few cases of pest problems relating to D. norwegica have been reported multiple times. The species is not endangered.
The tree wasp is a species of eusocial wasp in the family Vespidae, found in the temperate regions of Eurasia, particularly in western Europe. Despite being called the tree wasp, it builds both aerial and underground paper nests, and can be found in rural and urban habitats. D. sylvestris is a medium-sized wasp that has yellow and black stripes and a black dot in the center of its clypeus. It is most common to see this wasp between May and September during its 3.5 month colony cycle.
Dolichovespula adulterina is a species of parasitic social wasp. D. adulterina lives in the Palearctic and Nearctic regions but parasitise different host species depending on which region it inhabits. D. adulterina feeds on a variety of foods including insects, spiders, arthropods, meat, molluscs, fruit, nectar and larval secretions. D. adulterina is synonymous with D. arctica from the Palearctic region.
Vespula squamosa, the southern yellowjacket, is a social wasp. This species can be identified by its distinctive black and yellow patterning and orange queen. These yellowjackets are typically found in eastern North America, and its territory extends as far south as Central America. Within these territories, they create enormous, multiple-comb nests. The colonies may be either annual or perennial depending on the climate, and in many perennial nests, polygyny takes place. In addition, this species uses pheromones both as a sexual attractant and an alarm signal. This species feeds on insects and animal carcasses; it does not produce honey. V. squamosa, a social insect, has developed a parasitic relationship with the species V. vidua and V. maculifrons. Due to their painful, venomous stings, the species is considered a pest.
Worker policing is a behavior seen in colonies of social hymenopterans whereby worker females eat or remove eggs that have been laid by other workers rather than those laid by a queen. Worker policing ensures that the offspring of the queen will predominate in the group. In certain species of bees, ants and wasps, workers or the queen may also act aggressively towards fertile workers. Worker policing has been suggested as a form of coercion to promote the evolution of altruistic behavior in eusocial insect societies.
Apoica flavissima is a paper wasp found primarily in South America. The species is distinguishable by its light coloring, unique single comb nests, and nocturnal nature. A notable feature of this species is the size dimorphism between queens and workers. Unlike most Vespidae wasps, Apocia flavissima queens are smaller than their worker counterparts which results in unique intraspecies relationships.
Dolichovespula arenaria, also known as the common aerial yellowjacket, sandhills hornet, and common yellow hornet, is a species of wasp within the Dolichovespula genus widely distributed in the North American continent.
Belonogaster petiolata is a species of primitively eusocial wasp that dwells in southern Africa, in temperate or subhumid climate zones. This wasp species has a strong presence in South Africa and has also been seen in northern Johannesburg. Many colonies can be found in caves. The Sterkfontein Caves in South Africa, for example, contain large populations of B. petiolata.
Polistes biglumis is a species of social wasp within Polistes, the most common genus of paper wasp. It is distinguished mainly by its tendency to reside in montane climates in meadows or alpine areas. Selection pressure from the wasp's environment has led to several idiosyncrasies of its behavior and life cycle with respect to its relative species in the genus Polistes. It alone among paper wasps is often polyandrous. In addition, it has a truncated nesting season that gives rise to unique competitive dynamics among females of the species. P. biglumis wasps utilize an odor based recognition system that is the basis for all wasp to wasp interaction of the species. The wasp's life cycle is highly intertwined with that of Polistes atrimandibularis, an obligate social parasite wasp that frequently invades the combs of P. biglumis wasps.
Polistes sulcifer is a species of paper wasp in the genus Polistes that is found in Italy and Croatia. It is one of only three known Polistes obligate social parasites, sometimes referred to as "cuckoo paper wasps", and its host is the congeneric species Polistes dominula. As an obligate social parasite, this species has lost the ability to build nests, and relies on the host workers to raise its brood. P. sulcifer females use brute force, followed by chemical mimicry in order to successfully usurp a host nest and take over as the queen.
Ropalidia revolutionalis Ropalidia revolutionalis, the small brown paper wasp, is a diurnal social wasp of the family Vespidae. They are known for the distinctive combs they make for their nests, and they are mostly found in Queensland, Australia in the areas of Brisbane and Townsville. They are an independent founding wasp species, and they build new nests each spring. They can be helpful because they control insect pests in gardens. However, if threatened, they will sting humans and cause large amounts of pain.
Protopolybia exigua is a species of vespid wasp found in South America and Southern Brazil. These neotropical wasps, of the tribe Epiponini, form large colonies with multiple queens per colony. P. exigua are small wasps that find nourishment from nectar and prey on arthropods. Their nests are disc-shaped and hang from the undersides of leaves and tree branches. This particular species of wasp can be hard to study because they frequently abandon their nests. P. exigua continuously seek refuge from phorid fly attacks and thus often flee infested nests to build new ones. The wasps' most common predators are ants and the parasitoid phorid flies from the Phoridae family.
Parachartergus fraternus is a neotropical, swarm founding, polistine wasp species that is distributed throughout Central and South America. They live in nests in second growth tropical dry forests, near pasture fields, roadside areas, and urban areas as well. These wasps eat insects, such as caterpillars of Lepidoptera. They also drink nectar, honeydew, and water. The workers capture their prey during foraging. They also use venom to paralyze their prey in order to consume it later. P. fraternus wasps are not very aggressive and they do not attack when the nest is approached.
