Sperm competition and sperm length influence the rate of mammalian spermatogenesis.

摘要: Sperm competition typically favours an increased investment in testes, because larger testes can produce more sperm to provide a numerical advantage with rival ejaculates. However, interspecific variation testis size cannot be equated directly production rate—which is the trait ultimately selected under competition—because there are also differences between species proportion of spermatogenic tissue contained within and time it takes each sperm. Focusing on latter source variation, we phylogenetically controlled evidence for mammals that relatively large (and hence high level competition) have shorter duration cycle seminiferous epithelium consequently faster rate spermatogenesis, enabling males per unit time. Moreover, identify independent negative relationship length such spermatogenesis longer We conclude selects both increase overall production, evolutionary trade-off numbers may mediated via constraints imposed by selection