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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 ...
Eduardo R. S. Roldan   +1 more
openaire   +3 more sources

SPERM COMPETITION AND THE EVOLUTION OF NONFERTILIZING SPERM IN MAMMALS

Evolution, 1991
Nonfertilizing sperm with special morphologies have long been known to exist in invertebrates. Until recently, abnormal sperm in mammals were considered errors in production. Now, however, Baker and Bellis (1988, 1989) have proposed that mammalian sperm, like some invertebrate sperm, are polymorphic and adapted to a variety of nonfertilizing roles in ...
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Intracytoplasmic sperm injection

Molecular and Cellular Endocrinology, 2002
Intracytoplasmic sperm injection (ICSI) with ejaculated, epididymal or testicular spermatozoa was first successful in 1992 and has since become the widely accepted treatment for couples with severe male-factor infertility. The outcome of several thousands of ICSI cycles in terms of fertilization, embryo cleavage and implantation is similar to that for ...
Van Steirteghem, AndrĂ©   +2 more
openaire   +8 more sources

Sperm Capacitation and Acrosome Reaction in Mammalian Sperm

2016
Physiological changes that endow mammalian sperm with fertilizing capacity are known as sperm capacitation. As part of capacitation, sperm develop an asymmetrical flagellar beating known as hyperactivation and acquire the ability to undergo the acrosome reaction. Together, these processes promote fertilizing competence in sperm. At the molecular level,
Lis C. Puga Molina   +5 more
openaire   +3 more sources

The risk of sperm competition and the evolution of sperm heteromorphism

Animal Behaviour, 1998
Members of the Drosophila obscura species group exhibit sperm heteromorphism in which males simultaneously produce two different morphologies of sperm, short and long. Short sperm represent at least 50% of the ejaculate in several species but do not function in fertilization and thus, the evolutionary significance of this phenomenon is unknown ...
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Testes, Sperm, and Sperm Competition

2009
Robert Montgomerie, John L. Fitzpatrick
openaire   +2 more sources

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