Identification Atlas of the Vespidae (Hymenoptera, Aculeata) of the northeastern Nearctic region
Matthias Buck, Stephen A. Marshall, and David K.B. Cheung
Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
Species recognition. The queen of this rarely collected social parasite is easily recognised by its distinctive metasomal pattern that includes a pair of enclosed yellow spots on tergum 1, a black median mark with ‘ear’-like processes on tergum 2, and pairs of free to narrowly connected black spots on following terga. The male is most similar to V. acadica but possesses outstanding black hairs on at least the basal half of the hind tibia (absent in other species, but a few black hairs near base of tibia may be present in V. acadica). Further diagnostic characters are mentioned in the key.
Variation. Fore wing length 12.0–13.0 mm (♀♀, n = 4), ca. 10.0–11.5 mm (♂♂, n = 3). Female clypeus with three black discal spots, sometimes more or less confluent; male with a central black mark that reaches apical margin of clypeus. Female with lower gena black, enclosing a small to medium-sized yellow spot ventrally; male with a yellow postocular band interrupted near middle, or lower gena entirely black. Scape with or without a yellow anterior mark. Tergum 2 of one aberrant male (AB, Beaverlodge, DEBU) with a pair enclosed yellow discal spots similar to V. acadica. Pairs of black discal spots on female terga 3–5 usually free, rarely narrowly connected to black basal band.
Distribution. Canada: all provinces and territories. Northern U.S. including AK, south to NJ, MI, WI, ND, NM, AZ and CA. Widespread in Palaearctic region from Europe to Kamchatka, Japan and northwest China, south to Turkey, northern Pakistan and northern India (Miller 1961, Carpenter and Kojima 1997).
Biology. This species is an obligate social parasite in nests of other Vespula species and lacks the worker caste. Recorded hosts are V. acadica in North America and V. rufa in Europe (Akre et al. 1981).