Biology of social wasps

Social wasp colonies are almost always annual; generally the colony dies in late autumn or early winter in temperate countries. The queen starts a new next in the next spring.

Social wasps, especially the more well-known ones of the genera Vespa, Provespa, Polistes, Parapolybia, Ropalidia, Dolichovespula and Vespula (the latter 2 with fewer species in Asia), make their nest of of paper-like fibre, which they make out of wood pulp. They bite and tear fragments from tree trunks, rotting logs, plant fibres and even wooden man-made structures, then chew the fragments and mix them with saliva till they are soft. This material is then applied in layers to the surface, and dries to form a tough, fairly strong paper. The nests of Polistes and other Polistine species such as Parapolybia, Ropalidia etc. are open, often horizontal and plate-like, or a vertical column of cells. Nests of other common species are generally spherical and elongated to some extent and have an outer covering.

The adult wasps themselves feed on nectar from flowers or other sweet liquids, and also on a type of fluid produced by the larvae. Most wasps (queens and reproductive females being a possible exception) are unable to digest protein themselves. It is the larvae that are carnivorous, and the workers catch many insects every day to feed them. In this way they are useful as they capture many pest species in the process. However, some species may be pests to beekeepers by capturing honeybees. Many species are prevalent either in summer or autumn.

In late summer and early autumn,when the nest is at its peak,reproductive males and females(queens) are produced. During this time, there is still a rush of hunting activity, as the workers catch insects and other meat items to feed not only the larvae, but also the reproductives, to give them the nutrition they need to reproduce and hibernate. Some time after this, they fly out to mate. After a couple of weeks or months more, the colony dies, except for the young queens which go into hibernation and emerge the following spring to form new colonies.

Note that this is only a brief summary of the life cycle of a social wasp colony. This may vary between countries with different climates and seasons, and also between the species. Also, there are many other species of social wasps besides the common ones mentioned. Some of the species from the tropical rainforests have truly interesting habits and nesting behaviour! Some of these fascinating species will also be covered here.

Stages in a wasp's life
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