Akre, R.D., A. Greene, J.F. MacDonald, P.J. Landholt, and H.G. Davis. (1981). Yellowjackets
of North America, North of Mexico. U.S. Department of Agriculture, Washington, D.C. Handbook
Vespula austriaca, a rarely collected species, is widespread throughout the Boreal Region of North America (fig. 46). An obligatory social parasite of Palearctic V. rufa, V. austriaca does not possess a worker caste and is dependent on host workers to rear its brood of new males and queens. Various workers (Carpenter and Pack-Beresford, 1903; Pack-Beresford, 1901; Sharp, 1903; Weyrauch, 19,97) described certain aspects of the biology of V. austriaca and its host V. rufa as summarized in Spradber (1973a).
V. austriaca is sympatric with a number of potential V. rufa group hosts (Miller, 1961); however, our studies indicated that V. acadica was the most likely host. During the summer of 1978, two colonies of V. acadica, each with a V. austriaca queen, were collected in northern Idaho near the small town of Harvard. These are the first records of this social parasite being taken from nests of a Nearctic yellowjacket (Reed et al., 1979).
Reprinted with permission from: Miller, C.D.F. 1961 Taxonomy and Distribution of Nearctic Vespula. The Canadian Entomologist Supplement 22.
Color.—Black with yellow markings.
Structure.—Neuter caste lacking; malar space less than half as long as the penultimate antennal segment; apical margin of the female clypeus much projecting with prominent raised lateral angles; extensor surface of hind tibiae bearing long erect hairs, scattered over the entire length (Fig. 5); male genitalia as in Fig. 14.
Abdominal Color Patterns.—as in Figs. 42, 45.
Facial Color Pattern.—as in Fig. 77.
This is a Holarctic species which, though widespread throughout the Boreal region of North America, is rare in comparison to most others.
This species is relatively stable over its entire range.
Ecological Notes.—In Europe this species has been recorded from nests of Vespula rufa (Linné.). So far it has never been taken from a nest of a Nearctic species, however, an examination of its range indicates that it could be parasitic on a number of species especially those which have close structural affinities to V. rufa. Further study of this species should reveal its parasitic habits here.