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. Variations amongst individuals Although the wasps do not display much conspicuous variation that enables one to tell them apart with the naked eye, 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 associated with social hierarchy within the colonies. Males with smaller, regular patterns of spots are more aggressive and dominant over those with larger, irregular patterns. Similarly, females' appearance varies between individuals and is associated with their social rank. The larger and the more scattered the clypeus marks on the foundress, the higher the probability that she is dominant over other females. Distribution 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. Habitat P. dominula generally lives in temperate, terrestrial habitats such as chaparral, forest, and grassland biomes. They also have the propensity to colonize nearby human civilizations because man-made structures can act as great shelters and also are located close to the resources such as food. Spread within North America Behavioral adaptations of P. dominula have allowed it to expand outside its native range and invade the United States and Canada. While most Polistes species in the United States feed only on caterpillars, P. dominula eats many different types of insects. It