Data from: Multivariate sexual selection on ejaculate traits under sperm competition

Raw data used in multivariate selection analyses. These data include: experimental block number, male ID, number of successes (competitive fertilizations), number of failures (total fertilizations in block minus number successfully fertilized by the male), proportion of successful fertilizations, flagellum beat cross frequency (BCF), curvilinear velocity (VCL), path linearity (LIN), percentage of motile sperm, mean sperm head length and mean sperm flagellum length. The widespread prevalence of sperm competition means that ejaculates face intense sexual selection. However, prior investigations of sexual selection on gametes have been hampered by two difficulties: (1) deriving estimates of relative fitness from sperm competition trials that are comparable across rival male and female genotypes; and (2) obtaining measures of competitive fertilization success that are not confounded by post-zygotic effects. Here, we exploit the experimental tractability of a broadcast spawning marine invertebrate to overcome these challenges and characterise multivariate sexual selection on sperm traits when multiple ejaculates compete. In multi-male spawning events, we tracked real-time success of sperm using fluorescent tags that are visible inside fertilized eggs. We then used multivariate selection analyses to identify patterns of linear and non-linear sexual selection on multiple sperm morphology and motility traits. Specifically, we found non-linear selection against divergent combinations of sperm length, velocity and swimming path linearity. These patterns likely reflect the way different swimming strategies allow sperm to locate and track eggs. Our results demonstrate that there are overall patterns of selection on ejaculates across a biologically realistic range of ejaculate-ejaculate and ejaculate-female interactions; therefore, there is the potential for adaptive evolution of ejaculate traits under sperm competition.本数据集为多元选择分析（multivariate selection analyses）所用的原始数据，包含以下内容：实验区组编号（experimental block number）、雄性个体标识（male ID）、竞争性受精成功次数（competitive fertilizations）、失败受精次数（即某实验区组内总受精数减去该雄性个体的成功受精数，number of failures (total fertilizations in block minus number successfully fertilized by the male)）、成功受精比例（proportion of successful fertilizations）、鞭毛击打交叉频率（flagellum beat cross frequency, BCF）、曲线运动速度（curvilinear velocity, VCL）、路径线性度（path linearity, LIN）、运动精子占比（percentage of motile sperm）、平均精子头部长度与平均精子鞭毛长度。 精子竞争（sperm competition）现象广泛存在，这意味着射精产物（ejaculate）面临着强烈的性选择压力。然而，此前针对配子的性选择研究曾受限于两大难题：其一，如何从跨不同雄性与雌性基因型的精子竞争试验中推导得到可比较的相对适合度（fitness）估计值；其二，如何获取不受合子后效应（post-zygotic effects）干扰的竞争性受精成功度量指标。本研究借助体外排精海洋无脊椎动物（broadcast spawning marine invertebrate）的实验可操作性攻克了上述挑战，并在多份射精产物相互竞争的情境下，刻画了精子性状所受的多元性选择特征。在多雄性排精事件中，我们通过可在受精卵（fertilized eggs）内显现的荧光标记物（fluorescent tags）实时追踪精子的实际受精成功情况。随后我们运用多元选择分析方法，明确了多种精子形态（sperm morphology）与运动性状（sperm motility traits）所受的线性与非线性性选择模式。具体而言，我们发现存在针对精子长度、运动速度与游泳路径线性度的差异化组合的非线性选择。这类模式大概率反映了不同游泳策略如何帮助精子定位并追踪卵细胞。本研究结果表明，在符合生物学现实的射精-射精与射精-雌性交互范围内，射精产物整体存在可观测的选择模式；因此在精子竞争情境下，射精性状具备适应性进化（adaptive evolution）的潜力。