Sperm number trumps sperm size in mammalian ejaculate evolution
نویسندگان
چکیده
منابع مشابه
Sperm number trumps sperm size in mammalian ejaculate evolution.
Postcopulatory sexual selection is widely accepted to underlie the extraordinary diversification of sperm morphology. However, why does it favour longer sperm in some taxa but shorter in others? Two recent hypotheses addressing this discrepancy offered contradictory explanations. Under the sperm dilution hypothesis, selection via sperm density in the female reproductive tract favours more but s...
متن کاملSperm competition and the evolution of ejaculate composition.
We present a model of sperm competition that incorporates both sperm and nonsperm parts of the ejaculate. Our primary focus is on determining how ejaculate composition and size evolves as a function of the effects of seminal fluid on male reproductive success and as a function of asymmetry in sperm usage by females. The model predicts that different patterns of investment in sperm and seminal p...
متن کاملSperm competition influences sperm size in mammals.
Among mammals sperm competition leads to selection for increased sperm numbers but it is not known whether it also leads to changes in sperm size. Two contrasting theoretical predictions have been made. The first hypothesis relies on the assumption that there is a trade-off between sperm numbers and sperm size and predicts that, in species confronting sperm competition, there will be a concomit...
متن کاملSperm competition influences sperm size in mammals
Among mammals sperm competition leads to selection for increased sperm numbers but it is not known whether it also leads to changes in sperm size. Two contrasting theoretical predictions have been made. The first hypothesis relies on the assumption that there is a trade-off between sperm numbers and sperm size and predicts that, in species confronting sperm competition, there will be a concomit...
متن کاملNo evidence of trade-offs in the evolution of sperm numbers and sperm size in mammals.
Post-copulatory sexual selection, in the form sperm competition, has influenced the evolution of several male reproductive traits. However, theory predicts that sperm competition would lead to trade-offs between numbers and size of spermatozoa because increased costs per cell would result in a reduction of sperm number if both traits share the same energetic budget. Theoretical models have prop...
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ژورنال
عنوان ژورنال: Proceedings of the Royal Society B: Biological Sciences
سال: 2015
ISSN: 0962-8452,1471-2954
DOI: 10.1098/rspb.2015.2122