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Sperm competition: motility and the midpiece in primates
Matthew J Anderson1, Alan F Dixson
1Center for the Reproduction of Endangered Species, Zoological Society of San Diego, CA 92112-0551, USA. manderson@sandiegozoo.org
Nature
|April 5, 2002
Summary
Sperm midpiece volume is larger in primate species with multiple-partner mating systems and larger testes. This suggests sperm competition influences the evolution of sperm morphology in primates.
Area of Science:
- Evolutionary biology
- Reproductive biology
- Primate ecology
Background:
- Sperm competition occurs when ova are fertilized by gametes from multiple males.
- Male reproductive strategies vary significantly across primate species.
Purpose of the Study:
- To investigate the relationship between mating systems, testes size, and sperm morphology in primates.
- To determine if sexual selection via sperm competition has shaped sperm midpiece volume.
Main Methods:
- Comparative analysis of sperm midpiece volume across primate species.
- Correlation of sperm morphology with mating systems and relative testes size.
Main Results:
- Primate species with multiple-partner mating systems exhibit significantly larger sperm midpiece volumes.
- Larger relative testes size in males correlates with increased sperm midpiece volume.
- Species with single-partner mating systems show smaller sperm midpiece volumes and testes size.
Conclusions:
- Sexual selection driven by sperm competition has influenced the evolution of sperm midpiece volume in primates.
- Sperm morphology, specifically midpiece volume, is an adaptive trait shaped by reproductive pressures.
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