Polybioides raphigastra
| Polybioides raphigastra | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hymenoptera |
| Family: | Vespidae |
| Genus: | Polybioides |
| Species: | P. raphigastra |
| Binomial name | |
|
Polybioides raphigastra (Saussure, 1854) |
|
| Synonyms | |
|
Polybia sumatrensis |
|
Polybia sumatrensis
Polybioides raphigastra is a species of social wasp found in the forests of South East Asia and Indonesia. It has recently been placed in the tribe Ropalidiini. This species is known for the downward-spiraling shape of their nests, and for having colony sizes exceeding ten thousand members.
The Swiss entomologist Henri Louis Frédéric de Saussure described P. raphigastra in 1854. At the time, it was identified by the synonym Polybia sumatrensis de Saussure.
P. raphigastra is one of six known species that comprise the genus Polybioides. Four of these species live in South East Asia, Indonesia, and the Philippines, and the other two are located in equatorial Africa.Polybioides were recently included in the tribe Ropalidiini, which, along with Polistini, Epiponini, and Mischocyttarini, make up the subfamily Polistinae.
Other members of the genus include: Polybioides angustus, Polybioides gracilis, Polybioides melaina, Polybioides psecas, and Polybioides tabidus.
P. raphigastra bodies are composed of mostly dark areas, with lighter areas near the edge of segmented appendages. These dark areas are pale brown with light areas maintaining various shades of yellow.
The species nests in closed cavities such as caves and hollow trees. When nests are constructed within tree trunks, the trunks are often left entirely intact, with only small crevices giving access to the internal cavities that house the nest. In the trunk cavity, nests hang vertically with the envelope surrounding the nest directly attached to the inside of the cavity. Nests, often ovoidal in shape, may measure approximately 23 cm in length, with maximum diameters of 14.5 x 16 cm. Nests may contain well over ten thousand cells. Nests are egg-shaped and formed of a single, helicoidal comb that winds upon itself eight or nine times in a fashion so that each whorl is partially enclosed by the following one. Nests are entirely composed of very short plant hairs bound together by differing levels of secretion. Nest color is brown to yellowish, and the envelope may be darker than the cells inside. The outer envelope displays crescent-like patterns of colors varying from white to reddish brown. Each whorl on the nest is composed of two parts: a lower aspect constitutes the comb and an upper aspect that forms the envelope; leading to the number of layers of the envelope being roughly equivalent to the number of tiers of whorls. The curved structure, which curls spirally on itself in a series of layers, growing larger and larger may vaguely resemble the shell of a sea snail. Towards the center of each tier, the cells axes point downwards while near the edge of the envelope (the periphery) they are faced almost horizontal.The architecture of P. raphigastra nests appear to be unique among the Vespidae, though spiral combs may be found in other species of swarm-founding Ropalidiini and Epiponini. Additionally, its tendency to enwrap and protect previously built structures as it grows is similar to Agelaia areata.
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Wikipedia