Data supporting: Molecular, behavioural and morphological comparisons of sperm adaptations in a fish with alternative mating tactics

In species with alternative reproductive tactics, there is much empirical support that sneaker males have larger testes size and greater sperm numbers. However, support for higher sperm performance by sneakers is inconsistent. We used the sand goby (Pomatoschistus minutus) to test whether sperm performance differed between breeding-coloured males (small testes, but large mucus-filled sperm-duct glands; builds a nest lined with a sperm-containing mucus, provides care) and sneaker-morph males (no breeding colouration, large testes, rudimentary sperm-duct glands; no nest, no care). We compared motility (proportion motile sperm), velocity and longevity of sperm, between the two morphs. Furthermore, we compared gene expression of testes, and tested if the sperm-duct gland contents affected sperm performance, and if sperm morphometrics differed between male morphs. We found a clear difference in gene expression of testes between the male morphs with 109 transcripts differentially expressed be...在具有替代性繁殖策略（alternative reproductive tactics）的物种中，已有大量实证研究表明，偷配雄性（sneaker males）拥有更大的睾丸体积与更多的精子数量。然而，关于偷配雄性精子性能更优的结论却并不一致。本研究以沙鳢（Pomatoschistus minutus）为实验对象，旨在探究繁殖色雄性（breeding-coloured males）与偷配形态雄性（sneaker-morph males）之间的精子性能是否存在差异：前者睾丸体积较小，但拥有充满黏液的输精腺（sperm-duct glands），会构筑铺有含精子黏液的巢穴并抚育后代；后者无繁殖体色，睾丸体积较大，输精腺发育不全，既不筑巢也不抚育后代。本研究对比了两类雄性的精子运动率（motility，即活动精子占比）、运动速度与存活时长；此外，还对二者的睾丸基因表达（gene expression）进行了分析，检验了输精腺内容物对精子性能的影响，以及不同雄性形态间的精子形态学特征是否存在差异。研究结果显示，两类雄性的睾丸基因表达存在显著差异，共有109个转录本呈现差异表达……