Effect of the parasite Wohlfahrtia vigil on Microtus townsendii populations

This paper gives the first record of W. vigil parasitizing a wild species in Canada. The incidence of parasitism of the vole M. townsendii was at a maximum from August to mid-September. Of 1933 voles observed during this time, 5.4% were parasitized, and all age-classes were equally susceptible. Parasitism by W. vigil appeared to be facilitated by the presence of botflies (Cuterebra spp.). Survival of voles parasitized by W. vigil was severely affected, with only 5% living 2 weeks later.