Vol. 51 No. 2, 2012

Monogamous System in the Taiwan Vole Microtus kikuchii Inferred from Microsatellite DNA and Home Ranges

Jung-Sheng Wu, Po-Jen Chiang, and Liang-Kong Lin*

Department of Life Science, Tunghai Univ., 181 Taichung Port Road, Sec. 3, Taichung 407, Taiwan

Jung-Sheng Wu, Po-Jen Chiang, and Liang-Kong Lin (2012) The Taiwan vole Microtus kikuchii is considered socially monogamous based on indirect information of captive behaviors and home-range ecology. Genetic components of its mating system were not previously examined. We tested the hypotheses that M. kikuchii is both socially and genetically monogamous by combining field information of home ranges with genetic analysis of relationships among individuals. Trapping was conducted in the Hehuan Mt. area of Taroko National Park, central Taiwan, from June 2004 to Aug. 2005. We chose 16 microsatellite loci using primers designed for M. oeconomus and M. montebelli to amplify M. kikuchii DNA. Eleven loci produced clear, polymorphic banding patterns and were used for the genetic analysis. The homerange sizes of adults did not significantly differ between sexes or among seasons. For the 14 social units indicated by overlapping home ranges, 11 (78.6%) were male-female pairs. The other 3 social units involved more than 2 individuals. In two of these, ranges of a male-female pair overlapped ranges of their offspring and other individuals. The genetic analysis revealed that some of the male-female pairs identified by overlapping home ranges did not reproduce. Information based on the home-range data was not powerful enough to identify genetic components of M. kikuchiiʼs mating system and may provide misleading results. A parentage analysis based on microsatellite genotyping revealed litters (with a total 31 of offspring) sired by 18 males and 20 females. The only 2 males that fathered more than 1 litter did so in different years when their 1st mate was no longer present. None of the 9 litters with multiple offspring had more than 1 father. Home-range overlap was mostly between a single male and a single female and with their offspring. All pairs producing offspring were genetically monogamous. Our results strongly support the hypotheses that M. kikuchii is socially and genetically monogamous.

Key words: Genetic monogamy, Home range, Parentage analysis, Social monogamy.

*Correspondence: Tel: 886-4-23595845. Fax: 886-4-23595845. E-mail:lklin@thu.edu.tw