Results 41 to 50 of about 1,104,726 (307)
Why small males have big sperm: dimorphic squid sperm linked to alternative mating behaviours
BMC Evolutionary Biology, 2011 Background Sperm cells are the target of strong sexual selection that may drive changes in sperm structure and function to maximize fertilisation success. Sperm evolution is regarded to be one of the major consequences of sperm competition in polyandrous
Shiba Kogiku +5 more
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Media Peternakan, 2013 The objective of this study was to examine the relationship between sperm morphometry and sperm competition in local goats. Forty bucks were used in this study, consisted of 4 breeds namely Ettawa Grade Goat (EGG), Kejobong Goat (KJG), Kacang Goat (KCG),
S. B. Wibowo +2 more
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Sperm Viability Matters in Insect Sperm Competition [PDF]
Current Biology, 2005 Experimental studies in insects have shown how sperm competition can be a potent selective force acting on an array of male reproductive traits . However, the role of sperm quality in determining paternity in insects has been neglected, despite the fact that sperm quality has been shown to influence the outcome of sperm competition in vertebrates .
Garcı́a-González, Francisco +1 more
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Seminal fluid affects sperm viability in a cricket.
PLoS ONE, 2011 Recent studies have suggested that males may vary the quality of their ejaculates in response to sperm competition, although the mechanisms by which they do so remain unclear.
Leigh W Simmons, Maxine Beveridge
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Experimental evolution of sperm competitiveness in a mammal
BMC Evolutionary Biology, 2011 Background When females mate with multiple partners, sperm from rival males compete to fertilise the ova. Studies of experimental evolution have proven the selective action of sperm competition on male reproductive traits.
Simmons Leigh W, Firman Renée C
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Sperm competition in bats [PDF]
Proceedings of the Royal Society of London. Series B: Biological Sciences, 1997 (Uploaded by Plazi for the Bat Literature Project) Sperm competition is a widespread phenomenon influencing the evolution of male anatomy, physiology and behaviour. Bats are an ideal group for studying sperm competition. Females store fertile sperm for up to 200 days and the size of social groups varies from single animals to groups of hundreds of ...
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Sperm Viability and Sperm Competition in Insects [PDF]
Current Biology, 2002 Sperm quality plays an important role in vertebrates in determining which male has the advantage when two or more males compete to fertilize a female's ova. In insects, however, the importance of sperm quality has never been considered, despite sperm competition being widespread and well studied in this group.
Hunter, F.M, Birkhead, T.R
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Postcopulatory sexual selection is associated with reduced variation in sperm morphology. [PDF]
PLoS ONE, 2007 The evolutionary role of postcopulatory sexual selection in shaping male reproductive traits, including sperm morphology, is well documented in several taxa.
Sara Calhim +2 more
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Frontiers in Ecology and Evolution, 2015 How much of a fitness benefit is obtained by dominant males of external fertilizers from releasing ejaculates in synchrony with female egg-release when engaging in sperm competition, and what is the most important sperm trait for paternity in these ...
Torvald Blikra Egeland +4 more
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Sperm competition in birds [PDF]
Reviews of Reproduction, 1987 Sperm competition in birds occurs when a female is inseminated by more than one male during a single breeding cycle. Despite most birds being socially monogamous, sperm competition is widespread and results in frequent extra-pair paternity. Sperm competition is a fundamental part of sexual selection since it results in differential reproductive success
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