Cuterebra polita Coquillett is a primary parasite of the pocket gopher, Thomomys talpoides, in the western United States. It also occurs secondarily in other wild rodents that come into close contact with pocket gophers.Field studies disclosed pursuit, mating, and ovipositing at an aggregation site near Monte Cristo, Utah. Eggs were individually attached to fibrous roots suspended from the roof of shallow gopher burrows. This refinement of the host-parasite relationship has not previously been described for other North American cuterebrids.In the laboratory, 3 gravid females produced 186-357 viable eggs; about 85% were induced to hatch or hatched spontaneously after 12 days. Dissection of 1 of the females revealed another 886 eggs, for a total of 1243.Larvae were artificially introduced and developed in deer mice (Peromyscus maniculatus), domestic mice (Mus musculus), hamsters (Mesocricetus auratus), and meadow voles (Microtus montanus). The domestic rabbit (Orystolagus cuniculus) appeared refractory. The rate and success of development in the 4 rodent species was variable, but terminal larval development averaged about 22 days. Warbles appeared after 8 days in the rodents, and the majority of the cysts occurred in the posterior dorsal region.On the basis of larval characteristics, C. polita and C. thomomuris appear to be independent, valid species, though they share a common host.
