Reproduction of the female red-backed vole, Clethrionomys gapperi (Vigors), in the laboratory

Abstract

Female red-backed voles, Clethrionomys gapperi (Vigors), bred from wild stock trapped near Sudbury, Ontario, and maintained at 22 ± 2 °C and 18 h light and 6 h dark in the laboratory, showed no cyclic changes in their vaginal smear patterns. Copulation was followed by the development of corpora lutea in the ovaries, and it is concluded that the animal is an induced ovulator under the conditions of the experiment. The females released 5.1 ± 0.5 ova per ovulation, the gestation period was 18.5 ± 0.5 days, and litter size was 4.6 ± 0.2 pups in the laboratory.

Stimulus control of ovulation in red-backed voles (Clethrionomys gapperi)

“…Consistent with the observations of Langford and Clulow (1979), there was no regular cyclicity in the pattern of vaginal smears. All females except one in the paired condition and two in the unpaired condition reached the criterion of 2 consecutive days of estrus.…”

“…The Microtus and Clethrionomys genera are two prominent genera of microtine rodents, both of which appear to be induced ovulators (Breed, 1967;Clarke, Clulow, & Grieg, 1970;Langford & Clulow, 1979). Within both genera, females may ovulate not only after copulation, but also in response to proximal stimuli from males.…”

“…It is unlikely that the procedure of taking vaginal smears induced ovulation (see Hellwing, 1977, andLangford &CIulow, 1979). It seems more likely that airborne chemicals from males housed in the colony room reached the females.…”

“…Red-backed voles (Clethrionomys gapperi) are widely distributed in the United States and Canada and are amenable to laboratory study (Dewsbury, Baumgardner, Sawrey, & Webster, 1982). Langford and Clulow (1979) demonstrated that red-backed voles are induced ovulators. They found corpora lutea in the ovaries of 8 of 10 mated females and 0 of 10 unmated females.…”