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Effect of population density on reproduction in Microtus fortis under laboratory conditions
Qunhua Han1, Meiwen Zhang2, Cong Guo3
1Chinese Academy of Sciences Dongting Lake Station for Wetland Ecosystem Research, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture Changsha 410125 China Sichuan University College of Life Science Chendu 610064 China.
Abstract:
Between December 2011 and March 2012, the reproductive characteristics of Microtus fortis reared in the laboratory at different population densities were assessed. In all, 258 male and female voles were randomly divided into 4 groups and reared at densities of 2, 4, 6, and 8 animals per cage (sex ratio: 1:1). The results showed that the pregnancy rate (χ2 = 21.671, df = 3, P < 0.001) and first farrowing interval (F = 12.355, df = 3, P < 0.001) were significantly different among the different population density groups, but the mean litter size (mean ± SD) was not (F = 2.669, df = 3, P > 0.05). In particular, the reproductive index and sex hormone levels showed a significant difference among the different density groups studied.
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