Supporting data for the study from Effects of social and environmental contexts on multi-male mating and mixed paternity in socially monogamous female prairie voles

With whom and how often to mate are fundamental questions that impact individual reproductive success and the mating system. Relatively few studies have investigated female mating tactics compared to males. Here, we asked how differential access to mates influences the occurrence of mixed paternity and overall reproductive success in socially monogamous female prairie voles (Microtus ochrogaster). We created male- and female-biased sex ratios of prairie voles living in semi-natural outdoor enclosures. We ran paternity analyses to determine the identity and number of mating partners females had and the number of offspring produced. We found that 57.1% of females had litters fathered by two or more males when males outnumbered females, and 87.5% of females had litters with more than one father when females outnumbered males. However, the percentage of mixed paternity and the total number of embryos were not statistically different between social contexts. We determined that female fecundity (i.e. number of embryos) correlated with the number of male fathers in each litter across social contexts. Although our study did not support the hypothesis that social context directly influences female mating decisions, it did suggest that female multi-male mating might lead to increased fertilization success under semi-natural conditions.

与谁交配、交配频率如何，是影响个体繁殖成功率与交配系统的核心议题。相较于雄性，针对雌性交配策略的研究相对匮乏。本研究以社会一夫一妻制的雌性草原田鼠（Microtus ochrogaster）为对象，探究交配机会的差异如何影响混合父权的发生情况与整体繁殖成功率。我们在半自然室外围栏中构建了雄性偏倚与雌性偏倚的草原田鼠性比环境，并通过父权分析确定雌性的交配伴侣身份、数量以及所产后代数。结果显示，当雄性数量多于雌性时，57.1%的雌性所产幼崽的父本为2只或更多雄性；而当雌性数量多于雄性时，该比例升至87.5%。不过，两种社会环境下的混合父权比例与胚胎总数均无统计学差异。此外，我们发现，在两种社会环境下，雌性繁殖力（即胚胎总数）与每窝幼崽的父本数量呈显著相关。尽管本研究未支持“社会环境直接影响雌性交配决策”的假说，但结果表明，在半自然条件下，雌性与多雄性交配或可提升受精成功率。