Polistes erythrocephalus

Appearance

''Polistes erythrocephalus'' is about 21 millimetres in length and is characterized by its black thorax and abdomen. ''P. erythrocephalus'' bodies are typically narrower than those of its closest relatives such as ''Polistes annularis.'' The thorax is unmarked and the abdomen is slightly shinier than the rest of the body. This black body color contrasts with the color of its head which is a dull ferruginous color. On top of the head are ferruginous colored antenna which grow paler at the tips. ''P. erythrocephalus'' wings are dark bluish in color and have a noticeable glossy sheen. ''P. erythrocephalus'' legs are black with yellowish hues at the tarsi and knee joints.

For a long time ''P. erythrocephalus'' was considered to be a subspecies of ''P. canadensis'' and thus the two were often confused. However, ''P. canadensis'' possesses a ferruginous thorax, abdomen, and head. Additionally, the wings of ''P. canadensis'' are often a much lighter color than its body.

Distribution

''Polistes erythrocephalus'' is found in Central and South America. Although this species is most concentrated in Costa Rica and Panama, it has also been observed in Nicaragua, Venezuela, Columbia, Ecuador, Peru, Bolivia, and Southern Brazil. In Costa Rica, ''P. erythrocephalus'' nests are specifically highly concentrated in Finca Taboga and on the Osa Peninsula. In these countries ''P. erythrocephalus'' build nests in protected yet open areas both among humans and in the wild.

Behavior

The average ''P. erythrocephalus'' life cycle is 110 days with an observed range of 91–131 days. ''P. erythrocephalus'' go through the common ''Polistes'' maturation phases of eggs, larva, pupa, and adult. The egg stage is typically 14 days, the larva stage 29, the pupa stage is about 22 and the adult stage continues until death, which is on average 45 days.

Habitat

''Polistes erythrocephalus'' is found in Central and South America. Although this species is most concentrated in Costa Rica and Panama, it has also been observed in Nicaragua, Venezuela, Columbia, Ecuador, Peru, Bolivia, and Southern Brazil. In Costa Rica, ''P. erythrocephalus'' nests are specifically highly concentrated in Finca Taboga and on the Osa Peninsula. In these countries ''P. erythrocephalus'' build nests in protected yet open areas both among humans and in the wild.

Reproduction

Like most paper wasps ''Polistes erythrocephalus'' construct their nests by chewing plant and wood fibers with saliva to create a paper-maché-like material. When dried, their nests are somewhat horizontal and due to the divergence of cells have a concave upper surface. ''P. erythrocephalus'' nesting habits are very similar to ''P. annularis'' in that they prefer to build their nests in areas protected from direct sunlight, rain, wind, and other insects. The locations in which they find this protection vary greatly from the countryside to the city. ''P. erythrocephalus'' in urban areas have been observed to build nests under the eaves of roofs, under the wood of basement floors, in barns/stables, under bridges, and in lofts. This species also appears to prefer to build nests in close proximity to a water source. In more rural areas nests are found in clear areas such as the trunk of a solitary tree or the underside of a large ''Heliconia'' leaf. In these cases several nests can be built on the same tree at heights ranging from three to twenty feet off the ground. Again these nests are often in close proximity to a water source such as a stream.The reproductive phase lasts from the emergence of the first reproductives until the colony begins to decline and new reproductives disperse to form their own nests. During this time males wait on perches near nests in order to have the opportunity to mate with a virgin foundress. In some cases males will defend their perch in order to ensure the continuation of their genes. In the reproductive phase workers provide larva with food. This causes hierarchies among workers to emerge as more dominant individual workers forage significantly less than subordinates.As in many multifoundress wasp species, ''P. erythrocephalus'' foundresses compete viciously in order to become the dominant female. These interactions include chasing, biting, lunging, "sting threats," and aggressive mounting. Fights between individuals can sometimes even be fatal. These competitions lead to only one reproductively dominant female while the rest become subordinates. Once reproductive dominance is achieved then that female asserts great control over the behavior of the nest.A number of species take advantage of abandoned nests. An unidentified species of ''Trypoxylon'' uses the cells in order to raise its own brood. Moths of family Phycitidae use the cells as a safe place to form a cocoon. Spiders of families such as Salticidae, Linyphiidae, Oonopidae, and Scytodidae have been observed to use the nests for brooding and resting webs.

Food

''P. erythrocephalus'' are predatory wasps and feed on a wide variety of larva. A colony's predatory capacity depends on the number of their own larva present in their nest rather than the number of adults present. They are known to prey upon hornworm larva and were observed to eat an average of 0.5 hornworm larva per day .

Predators

One of the most devastating predators of ''P. erythrocephalus'' are army ants such as ''Eciton burchellii.'' These ants attack wasp nests and consume the larva and pupa, often destroying the nest in the process. ''P. erythrocephalus'' has not been observed to have any ability to defend their nests from such predators. However, they will attack and sting larger slow moving threats such as humans if they get within 1–2 meters of a nest.

The most common symbiont found in ''P. erythrocephalus'' nests is ''Pachysomoides stupida,'' a type of parasitic ichneumon. Papery cocoons of ''Pachysomoides stupida'' are found in many ''P. erythrocephalus'' nests while adults are seldom found. Other parasites of ''P. erthrocephalus'' include some species of ''Oxysarcodexia'' or flesh flies and ''Brachymeria conica'' . Both these species parasitize the larva and pupa of ''P. erythacephalus.'' Additionally, some ''Xenon'' species parasitize ''P. erythrocephalus'' adults, acting as permanent entomophagous endoparasites by dwelling in the abdomen.

Microlepidoptera larva have been observed to feed on the excretory waste of wasp larva.