Results 271 to 280 of about 1,104,726 (307)

Sperm Competition

Encyclopedia of Animal Behavior, 2010
N. Wedell
openaire   +2 more sources

Sperm Competition

Encyclopedia of Animal Cognition and Behavior, 2019
K. L. Durrant
openaire   +2 more sources

Sperm Competition Theory

Encyclopedia of Evolutionary Psychological Science, 2016
Clint D Kelly, Michael D Jennions
openaire   +2 more sources

Sperm Competition

2023
Abstract Sperm competition is a form of intrasexual competition in which the sperm of two or more males concurrently occupy the reproductive tract of a single female and compete to fertilize an available ovum. As a nonmonogamous species, humans have been subject to selection pressures associated with sperm competition.
Valerie G. Starratt, Todd K. Shackelford
openaire   +1 more source

Sperm competition and the evolution of sperm form and function in mammals.

Reproduction in domestic animals = Zuchthygiene, 2019
Sperm competition is a powerful selective force that has influenced many reproductive traits in males and females although additional evolutionary explanations may help to understand the diversity of mammalian reproduction.
E. Roldan
semanticscholar   +1 more source

Mechanisms of sperm competition

Trends in Ecology & Evolution, 1990
Sperm competition occurs when two (or more) males inseminate a single female during a reproductive cycle, but what determines which one of them will fertilize her eggs? Is it simply a lottery, or are there some more complex rules by which matings are translated into offspring?
T R, Birkhead, F M, Hunter
openaire   +2 more sources

Sperm competition in mammals

Trends in Ecology & Evolution, 1989
Female promiscuity can lead to the spermatazoa of several males 'competing' to fertilize the ova of a single female. Such promiscuity is relatively common among mammals and has resulted in a suite of adaptations associated with sperm competition. In the last decade, laboratory scientists using experimental techniques have clarified the physiological ...
J R, Ginsberg, U W, Huck
openaire   +2 more sources

Sperm competition games: sperm selection by females

Journal of Theoretical Biology, 2003
We analyse a co-evolutionary sexual conflict game, in which males compete for fertilizations (sperm competition) and females operate sperm selection against unfavourable ejaculates (cryptic female choice). For simplicity, each female mates with two males per reproductive event, and the competing ejaculates are of two types, favourable (having high ...
M A, Ball, G A, Parker
openaire   +2 more sources

Sperm competition influences sperm size in mammals

Proceedings of the Royal Society of London. Series B: Biological Sciences, 1991
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 ...
M, Gomendio, E R, Roldan
openaire   +2 more sources

Sperm size and sperm competition in birds

Proceedings of the Royal Society of London. Series B: Biological Sciences, 1992
In a sample of 20 species of North American passerine birds we found no relation between sperm size and mating system like that previously reported in mammals (Gomendio & Roldan (Proc. R. Soc. Lond. B 243, 181 (1991)). Instead, we found a positive correlation between sperm length and the length of female sperm storage tubules (SSTS) and a negative ...
J V, Briskie, R, Montgomerie
openaire   +2 more sources