Polistes dominula

The European paper wasp (Polistes dominula) 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 dominant females are the principal egg layers, while the subordinate females ('auxiliaries') or workers primarily forage and do not lay eggs. This hierarchy is not permanent, though; when the queen is removed from the nest, the second-most dominant female takes over the role of the previous queen. Dominance in females is determined by the severity of the scatteredness in the coloration of the clypeus (face), whereas dominance in males is shown by the variation of spots of their abdomens. P. dominula is common and cosmopolitan due to their exceptional survival features such as productive colony cycle, short development time, and higher ability to endure predator attacks. These wasps have a lek-based mating system. Unlike most social insects, 35% of P. dominula wasps in a colony are unrelated. It is considered an invasive species in Canada and the United States. The European paper wasp was originally described in 1791 by Johann Ludwig Christ as Vespa dominula. The specific epithet dominula is a noun meaning 'little mistress', and following the International Code of Zoological Nomenclature, species epithets which are nouns do not change when a species is placed in a different genus. Authors who were unaware that dominula was a noun have misspelled the species name as 'dominulus' for decades. Another cause of the confusion in the species' name was the ambiguous distinction between masculine and feminine genitive nouns. P. dominula is often referred to as the European paper wasp because of its native distribution and its nests, which are constructed from paper and saliva. It is also frequently referred to in older literature as Polistes gallicus, a separate species with which it was often confused. Little variation occurs among individuals of P. dominula; the wing lengths of males range from 9.5 to 13.0 millimetres (0.37 to 0.51 in), while those of females range from 8.5 to 12.0 millimetres (0.33 to 0.47 in). Its body is colored entirely yellow and black, similar to that of Vespula germanica, one of the most common and aggressive wasps in its native range. The female mandible is black and sometimes has a yellow spot. Females have a black subantennal mark that rarely has a pair of small, yellow spots. The female vertex sometimes has a pair of small, yellow spots behind the hind ocelli. Females have yellow, comma-shaped scutal spots. Although it is difficult to find conspicuous variations amongst individuals with bare eyes, definite features are unique to each individual. For example, the abdominal spots on males of P. dominula vary in sizes, locations, and patterns. They act as sexually selective signals and also are used to determine social hierarchy within the colonies. Males with smaller, regular patterns of spots were more aggressive and dominant over those that had larger, irregular patterns. Similarly, morphology of females also varies between individuals. The larger and the more scattered the clypeus marks on the foundress are, the higher the chance for her to be dominant over other females. The native range of P. dominula covers much of southern Europe and North Africa, and temperate parts of Asia as far east as China. It has also been introduced to New Zealand, Australia, South Africa, and North and South America. Since the mid-1980s, the population of P. dominula has expanded to rather cooler regions, especially towards northern Europe. Global warming is speculated to have raised temperatures of certain areas, allowing P. dominula to expand to originally cooler regions. The first North American occurrence of P. dominula was reported in Massachusetts in the late 1970s, and by 1995, this species had been documented throughout the northeastern USA. However, the species is also likely present in additional states, but has just not yet been reported. Although detailed mechanisms of the species' dispersal are still unknown, some number of individuals, including the foundresses, may have hidden inside transportable items such as shipping crates, trailers, boats, or other human-made structures used during international trading between countries.