Postcopulatory Sexual Selection and Sperm Morphology in Birds
Author Information
Author(s): Calhim Sara, Immler Simone, Birkhead Tim R.
Primary Institution: University of Sheffield
Hypothesis
Intraspecific variation in sperm morphology is driven by the level of postcopulatory sexual selection in passerine birds.
Conclusion
Postcopulatory sexual selection reduces variation in sperm morphology towards a species-specific optimum.
Supporting Evidence
- Intermale variation in sperm morphology decreases with increased postcopulatory sexual selection.
- The study used two indices of sperm morphology variation and two indices of postcopulatory sexual selection.
- Results suggest that postcopulatory sexual selection acts as a stabilizing force in sperm morphology evolution.
Takeaway
This study found that when male birds face more competition after mating, their sperm shapes become more similar to each other.
Methodology
The study analyzed sperm morphology in 18 species of passerine birds using measures of sperm competition and phylogenetic methods.
Limitations
The study may not account for all factors influencing sperm morphology variation.
Participant Demographics
18 species of passerine birds were studied.
Statistical Information
P-Value
p<0.001
Digital Object Identifier (DOI)
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