Male investments in high quality sperm improve fertilization success, but may have negative impact on offspring fitness in whitefish

Many ejaculate traits show remarkable variation in relation to male social status. Males in disfavoured (subordinate) mating positions often invest heavily on sperm motility but may have less available resources on traits (e.g., secondary sexual ornaments) that improve the probability of gaining matings. Although higher investments in sperm motility can increase the relative fertilization success of subordinate males, it is unclear whether status-dependent differences in sperm traits could have any consequences for offspring fitness. We tested this possibility in whitefish (Coregonus lavaretus L.) by experimentally fertilizing the eggs of 24 females with the sperm of either highly-ornamented (large breeding tubercles, dominant) or less-ornamented (small tubercles, subordinate) males (split-clutch breeding design). In comparison to highly-ornamented individuals, less-ornamented males had higher sperm motility, which fertilized the eggs more efficiently, but produced embryos with impaired...诸多射精相关性状会随雄性社会地位展现出显著变异。处于不利（从属）交配地位的雄性通常会在精子活力（sperm motility）上投入大量资源，但在可提升交配成功率的性状（如第二性征饰器（secondary sexual ornaments））方面可支配的资源相对不足。尽管提升精子活力的投入可提高从属雄性的相对受精成功率，但目前仍不清楚精子性状的地位依赖性差异是否会对子代适合度（offspring fitness）产生影响。本研究以白鲑（Coregonus lavaretus L.）为实验材料，采用分卵授精繁殖设计（split-clutch breeding design），将24条雌性的卵子分为多个子批次，分别使用具发达繁殖结节的优势雄性以及具小型繁殖结节的从属雄性的精子进行人工授精，以此检验这一假说。与具显著饰器的雄性个体相比，饰器退化的雄性精子活力更高，卵子受精效率更强，但所产生的胚胎却存在发育受损……