Data from: Lifetime reproductive success, selection on lifespan and multiple sexual ornaments in male European barn swallows

Natural and sexual selection arise when individual fitness varies according to focal traits. Extra-pair paternities (EPPs) can affect the intensity of selection by influencing variance in fitness among individuals. Studies of selection require that individual fitness is estimated using proxies of lifetime reproductive success (LRS). However, estimating LRS is difficult in large, open populations where EPPs cause reallocation of biological paternity. Here we used extensive field sampling to estimate LRS in a population of barn swallows (Hirundo rustica) to estimate selection on lifespan and ornamental traits of males. We found selection on lifespan mediated both by within- and extra-pair fertilization success and selection on tail length mediated by within- but not extra-pair fertilization success. In addition, we found selection on tail white spots via extra-pair fertilization success after controlling for selection on other traits. These results were not confounded by factors that hamper studies of LRS, including non-exhaustive sampling of offspring and biased sampling of males. Hence, natural and sexual selection mediated by LRS operates on lifespan, tail length and size of the tail white spots in barn swallows.

当个体适合度依据目标性状发生变异时，自然选择与性选择便会产生。婚外父权（extra-pair paternities，EPPs）可通过改变个体间适合度的方差，影响选择的强度。选择相关研究需借助终生繁殖成功率（lifetime reproductive success，LRS）的代理指标来估算个体适合度。然而，在存在EPPs导致生物学父权重新分配的大型开放种群中，估算LRS颇具难度。本研究通过大规模野外采样，对家燕（Hirundo rustica）种群的LRS进行估算，以此分析雄性寿命与装饰性性状所受的选择作用。研究发现，雄性寿命所受的选择同时受配对内与配对外受精成功率的介导，而尾长所受的选择仅受配对内受精成功率的影响，不受配对外受精成功率的作用。此外，在控制其他性状的选择效应后，我们发现尾白斑大小受配对外受精成功率介导的选择作用。上述结果未受干扰LRS研究的因素影响，包括子代采样不全面以及雄性采样偏倚。综上，由LRS介导的自然选择与性选择，对家燕的寿命、尾长以及尾白斑大小这三个性状产生作用。