Data from: Male sperm storage compromises sperm motility in guppies

Sperm senescence can have important evolutionary implications due to its deleterious effects on sperm quality and offspring performance. Consequently, it has been argued that polyandry (female multiple mating) may facilitate the selection of younger, and therefore competitively superior, sperm when ejaculates from multiple males compete for fertilization. Surprisingly, however, unequivocal evidence that sperm ageing influences traits that underlie sperm competitiveness is lacking. Here, we used a paired experimental design that compares sperm quality between ‘old’ and ‘young’ ejaculates from individual male guppies (Poecilia reticulata). We show that older sperm exhibit significant reductions in sperm velocity compared with younger sperm from the same males. We found no evidence that the brightness of the male's orange (carotenoid) spots, which are thought to signal resistance to oxidative stress (and thus age-related declines in sperm fitness), signals a male's ability to withstand the deleterious effects of sperm ageing. Instead, polyandry may be a more effective strategy for females to minimize the likelihood of being fertilized by aged sperm.,datasetit is a paired dataset describing sperm viability and sperm velocity assessed when sperm were young or old. Please see text for details.sp ageing.csv,

精子衰老会对精子质量与后代适合度产生有害影响，因此具有重要的进化意义。据此，有观点提出，当多个雄性的射精精子竞争受精机会时，一妻多夫制（polyandry，雌性多次交配）或可助力选择更年轻、因而在竞争中更具优势的精子。然而令人意外的是，目前仍缺乏确凿证据，证明精子衰老会影响精子竞争力相关的性状。本研究采用配对实验设计，比较了雄性孔雀鱼（Poecilia reticulata）个体“衰老”与“年轻”射精样本的精子质量。研究结果显示，相较于同一雄性的年轻精子，衰老精子的运动速度显著降低。我们未发现证据表明，雄性的橙色（类胡萝卜素carotenoid）斑点亮度——该斑点被认为可传递其抗氧化应激能力，以及由此关联的精子适合度随年龄衰退的情况——能够体现雄性抵御精子衰老有害影响的能力。换言之，对雌性而言，一妻多夫制或许是降低被衰老精子受精概率的更有效策略。本数据集为配对数据集，记录了精子处于年轻或衰老状态时的精子活力与运动速度评估结果，详细信息请参见正文。相关数据文件为sp ageing.csv。