Vespula atropilosa, also known as the prairie yellowjacket, is a black and yellow social wasp that forms annual colonies.

[3] The prairie yellowjacket can be found in the Western and Midwestern United States as well as parts of southern Canada.

[2] It builds its nests underground and prefers large open areas such as pastures and golf courses.

Prairie yellowjackets are not considered pests but are commonly found in backyards in the Pacific Northwest.

[9] Bohart and Bechtel (1957) considered it a subspecies of Vespula rufa but Miller (1961) recognized it as a unique species.

[3] Regarding the body, the metasomal tergites are covered with long straight hair, the black central region of the apex of the second gastral tergum is pointed, and the male aedeagus is saddle-shaped.

[3] Vespula atropilosa is found in western North America in Canada and the United States.

More specifically it is found in the Western and Midwestern United States ranging from Seattle to Arizona and in parts of southern Canada such as Alberta and British Columbia.

[3] Nests are typically subterranean and found in open areas such as dry fields and pastures.

[9] V. atropilosa often continue to excavate unused rodent tunnels in order to expand the nest.

[7] While searching for potential nest sites, queens will also visit flowers to obtain nectar.

Successful queens hang a pedicel of fibers on roots clinging to the roof of the burrow about 15–20 cm from the entrance.

[7] Prey theft occurs when V. atropilosa are confined in screenhouses but not when they are foraging in their natural habitat.

[7] It is typical for copulations to only last a minute on average due to frequent interruptions by competing males.

[7] In order to maintain close contact during mating, males grasp tightly to the queen's thorax.

Social wasps live in altruistic colonies consisting of one queen and her many offspring who are workers (daughters) or reproductives (sons).

This system of sex determination results in daughters from a single father being more related to each other than to their mother.

Since workers are so closely related to their sisters, there is a genetic incentive to practice kin altruism.

Workers catch a wide range of prey, most commonly insects of the orders Hemiptera mainly of the suborder homoptera (for example aphids, cicadas, and leafhoppers), Lepidoptera (moths and butterflies), and Diptera (flies).

[7] Vespula atropilosa will prey on any insect of the correct size that lacks chemical or behavioral defense mechanisms.

[7] Like Vespula pensylvanica, V. atropilosa primarily preys on adult Diptera, Homoptera, Lepidoptera larvae, and grasshoppers.

[7] Adult Cryptophagus pilosus, a species of beetle, has been found in some Vespula atropilosa nests.

[9] Larvae of C. pilosus were not found in nests in the field but were produced in large numbers in V. atropilosa colonies that were transplanted into screenhouses.

[9] Infestations of C. pilosus occurs late in the colony cycle typically after nest deterioration has begun.

Fannia larvae are found at the bottom of nest cavities and it is believed that these flies may be coprophagous.

[13] Since prairie yellowjackets are predators of other insects, they have the benefit of getting rid of local pests such as lacebugs and caterpillars.

[14] While venom may occasionally be used in intraspecies conflicts, it is more frequently used to defend the colony against macropredators and predators encountered during foraging, including humans.

Yellowjackets coming to retrieve the bait will usually fall into the water after consuming the food and will drown.

[8] The most effective traps should be set up early so that queens coming out of hibernation can be captured before they are able to initiate colonies.