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Estrus induction in four species of voles (Microtus)
S A Taylor1, A L Salo, D A Dewsbury
1University of Florida, Gainesville 32611.
Abstract:
Male-induced estrus was examined in montane (Microtus montanus), meadow (M. pennsylvanicus), prairie (M. ochrogaster), and pine (M. pinetorum) voles. Duration of male contact needed for receptivity, effects of parity, and vaginal cytology were assessed. Among nulliparous females, montane voles attained receptivity with less male contact than prairie voles. Meadow and pine voles showed very low receptivity rates. Among parous females, montane and meadow voles did not differ in duration of male contact needed for receptivity and required less than prairie voles. Overall, parous females had higher receptivity rates than nulliparous females. When isolated from males, prairie and pine voles had more leukocytes and fewer cornified cells in vaginal smears than montane or meadow voles. Species differences in estrus induction are discussed in relation to species differences in social organization.
Insights
Male voles can induce estrus in females, but the effectiveness varies by species and female parity. Parity generally increases receptivity rates across all studied vole species.
Area of Science:
- Reproductive biology
- Behavioral ecology
- Mammalian reproduction
Background:
- Male presence can influence female reproductive cycles in various rodent species.
- Understanding species-specific responses to male pheromones is crucial for reproductive biology.
Purpose of the Study:
- To investigate male-induced estrus across four vole species: montane (Microtus montanus), meadow (M. pennsylvanicus), prairie (M. ochrogaster), and pine (M. pinetorum).
- To determine the duration of male contact required for female receptivity.
- To assess the influence of parity and analyze vaginal cytology in relation to estrus induction.
Main Methods:
- Controlled exposure of nulliparous and parous female voles to males.
- Measurement of the time required for females to reach estrus.
- Collection and analysis of vaginal smears to assess cellular composition (leukocytes, cornified cells).
Main Results:
- Nulliparous montane voles required less male contact for receptivity than prairie voles; meadow and pine voles showed low rates.
- Parous montane and meadow voles required less male contact than prairie voles, with no significant difference between montane and meadow.
- Parous females exhibited higher receptivity rates than nulliparous females across species.
- Vaginal smears indicated differences in estrus timing, with prairie and pine voles showing more leukocytes and fewer cornified cells when isolated from males.
Conclusions:
- Species-specific differences in male-induced estrus exist among voles, influenced by social organization.
- Parity significantly enhances female receptivity to male-induced estrus.
- Vaginal cytology provides insights into the timing and physiological state related to estrus induction in voles.