Strategic adjustments in sperm production within and between two island populations of house mice

Sperm production is physiologically costly. Consequently, males are expected to be prudent in their sperm production, and tailor their expenditure according to prevailing social conditions. Differences in sperm production have been found across island populations of house mice that differ in the level of selection from sperm competition. Here, we determined the extent to which these differences represent phenotypic plasticity and/or population divergence in sperm production. We sourced individuals from two populations at the extreme levels of sperm competition, and raised them under common-garden conditions while manipulating the social experience of developing males. Males from the high-sperm competition population produced more sperm and better quality sperm than did males from the low-sperm competition population. In addition, males reared under a perceived “risk” of sperm competition produced greater numbers of sperm than males reared with “no risk.” However, our analyses revealed t...精子产生存在生理成本。因此，雄性个体理应审慎调控精子产生过程，并依据当前社会环境调整精子投入策略。已有研究发现，不同岛屿家鼠种群的精子产生水平存在差异，且这种差异与种群面临的精子竞争（sperm competition）选择强度相关。本研究旨在明确，这些种群间的精子产生差异究竟在多大程度上源于表型可塑性，抑或是种群间的精子产生性状遗传分化。我们采集了两个处于极端精子竞争强度水平的家鼠种群个体，在同质园实验条件（common-garden）下进行饲养，并对发育阶段雄性的社会经历进行操控处理。实验结果显示，相较于来自低精子竞争强度种群的雄性，来自高精子竞争强度种群的雄性产生的精子数量更多、质量更优。此外，处于感知存在精子竞争风险的饲养环境中的雄性，其精子产生量高于处于"无风险"环境中的雄性。然而，本研究的分析结果显示……