Data from: Long-term effect of social interactions on behavioral plasticity and lifetime mating success

Behavioral traits often change over an individual's lifetime. Experience, physiological senescence and age-dependent differences in optimal behavior can, in theory, all cause longitudinal behavioral changes. Yet most studies of behavioral plasticity and selection on behavior focus on short-term population-level responses to social factors such as conspecific density or sex ratio. Longer-term effects of social interactions on individual behavior have rarely been tested. Here, we tested these effects by exposing male water striders (Hemiptera: Gerridae) to two different social conditions throughout their lifetime: we call these the non-social and social treatments. We then measured each male's lifetime mating success and individual behavioral plasticity by observing four different behaviors (exploring a novel environment, dispersal ability, sex recognition sensitivity, and tendency to remount a resistant female after being dislodged) every two weeks. The social environment influenced individual variation in behavioral plasticity as well as population-level behavioral plasticity. Moreover, when we calculated linear selection gradients of individual behavioral traits, and their plasticities, on lifetime mating success, male remounting tendency and individual plasticity in exploration ability were likely to be the most important factors explaining variation in male lifetime mating success. In conclusion, the variation in social interactions throughout an individual's lifetime contributes to the individual variation in behavioral plasticity, which can significantly affect a male's lifetime fitness.行为性状往往会随个体的生命周期发生动态变化。理论上，个体的生活经历、生理衰老以及最优行为的年龄依赖性差异，均可导致纵向的行为改变。然而，当前绝大多数关于行为可塑性（behavioral plasticity）以及行为选择的研究，均聚焦于种群层面对同种密度、性比等社会因素的短期响应。社会互动对个体行为的长期效应，却极少得到实证检验。 本研究以雄性水黾（Hemiptera: Gerridae）为实验对象，在其整个生命周期中设置两种不同的社会环境处理——分别命名为非社会处理组与社会处理组，以此检验上述效应。随后，我们每两周对四种行为（探索新环境的行为、扩散能力、性识别敏感度，以及被驱赶后重新附着抵抗性雌虫的倾向）进行观测，以此量化每只雄性的终身交配成功率与个体行为可塑性。 研究结果显示，社会环境同时影响了行为可塑性的个体间变异与种群水平的行为可塑性。此外，当我们针对终身交配成功率计算个体行为性状及其可塑性的线性选择梯度（linear selection gradients）时发现，雄性的重新附着倾向与探索能力的个体可塑性，可能是解释雄性终身交配成功率变异的核心因素。 综上，个体生命周期内社会互动的变异，会推动行为可塑性的个体间差异，而这一差异可显著影响雄性的终身适合度（lifetime fitness）。