Data from: 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 that phenotypic plasticity in sperm production was greater for individuals from the high-sperm competition population. Our results are thus consistent with both population divergence and phenotypic plasticity in sperm production, and suggest that population level of sperm competition might affect the degree of adaptive plasticity in sperm production in response to sperm competition risk.精子生成在生理层面存在能量代价。因此，雄性个体在精子生成过程中应秉持审慎策略，并根据当前所处的社会环境调整其精子投入。研究发现，精子竞争（sperm competition）选择压力存在差异的家鼠岛屿种群间，精子生成水平存在显著差异。本研究旨在明确这些差异在多大程度上源于精子生成层面的表型可塑性（phenotypic plasticity）和/或种群分化。我们从精子竞争压力处于两个极端水平的种群中采集实验个体，在同质园饲养条件（common-garden conditions）下对其进行培育，同时操控发育中雄性的社会经历。结果显示，相较于来自低精子竞争压力种群的雄性个体，来自高精子竞争压力种群的雄性个体所产生的精子数量更多、质量更优。此外，处于感知到精子竞争"风险"环境下饲养的雄性个体，其精子生成量高于处于"无风险"环境下饲养的雄性个体。不过，本研究的分析结果表明，来自高精子竞争压力种群的个体，其精子生成的表型可塑性更强。综上，本研究结果与精子生成层面的种群分化和表型可塑性均相符，且表明种群的精子竞争压力水平或可影响雄性针对精子竞争风险所产生的适应性表型可塑性程度。