|scientific name Vespula atropilosa |
common name Prairie Yellowjacket
Neartic species limited to northern region in prairies and grasslands. This species is less abundant in dense forests.
The colony starts in late April or May and decline in late September or October and the nest remain from spring to fall.
This species is black with yellow markings; size between 10 mm and 15 mm. Head: the malar space is below than half as long as the penultimate antennal segment; the occipital carina is incomplete; the ventral part of the scape is yellow opposite the dorsal part of the scape is black. Metasoma: the metasomal tergites are covered with long straight hairs; the central black region of the apex of the second gastral tergum is pointed; male aedeagus with saddle-shaped portion. In some locations the male exhibits two different abdominal color patterns: a xanthic phase with more black than yellow and a melanic phase with more yellow than black (Miller 1961, VanDyk 2003).
The Prairie Yellowjacket is a social species with annual colonies. In later April or early May the queens emerge from diapauses and them looking for nesting places, generally they fly 20 cm above the ground; most queens begin the nest in deserted rodent burrows (Akre et al. 1976). The successful queen burrows about 10-30 cm underground, aerial nest are uncommon. The queen adds cells inside the nest, she lays eggs and takes care of the larvae, the first workers emerge in early June and the queen doesn’t leave the nest again. The workers search food and fibers, care the larvae, clean the cells, feed the queen, the larvae and the males, they exhibit trophallaxis, mauling and ovoposition behavior, and also they protect the colony (Akre et al. 1976). The average of lifespan of a worker is 48 days. The males emerge in mid August, finally the colony decline in September. For the workers the life cycle is completed in approximately 75 days, the queens live more than 5 months. Inside the nest the pupal parasite Sphecophaga vesparum, affect adversely the development of young colonies, S. vesparum may destroy new colonies or retard the normal growth of the colony, the Prairie Yellowjackets workers tend to ignore S. vesparum even if they touch them with the comb (MacDonald et al. 1975, Akre et al. 1976)
This species is common and this is not reported in vulnerability status.
They feed regularly on live prey. They are mostly predators of spiders, harvestmen, caterpillars, flies, hemipterans, soft beetles, butterflies, moths and other bugs, however, this species avoid crickets and slugs. The adults carry their prey or part of them to the nest to feed their larval states. They also feed of flower nectar or sweet substances (Akre et al. 1976).
This species is restricted to western of North America from Canada to United States. In Canada the species is distributed from central British Columbia to south and east in southern Alberta. In United States this species ranging from Seattle to Arizona. Alberta: Lethbridge, Medicine Lake, Pincher, Waterton. British Columbia: Crankbrook, Fairview, Kamloops, Merrit, Oliver, Penticton, Summerland, Vernon. United States: Arizona, Colorado, Idaho, Montana, Nevada, Oregon, South Dakota, Utah, Washington, Wyoming (GBIF 2011, Miller 1961).
This species is substituted for Vespula acadica in dense forest. Some V. atropilosa males have an intermediate color pattern with V. acadica, however, Miller (1958) suggest that they are the result of hybridization process between these species or parallel evolution, but Miller (1961) recognized the identity of both species as good species.
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