ArticleBMC evolutionary biology2018
Is sperm morphology functionally related to sperm swimming ability? A case study in a wild passerine bird with male hierarchies.
Article in BMC evolutionary biology, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.
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Who cites it
6 citing papers in PubMed.
- Post-copulatory competition in a social monogamy system: Sperm morphology correlates with components of reproductive success.PloS one · 2025Article
- Selection on sperm size in response to promiscuity and variation in female sperm storage organs.Journal of evolutionary biology · 2023Article
- Flagellum tapering and midpiece volume in songbird spermatozoa.Journal of morphology · 2022Article
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- Methodological considerations for examining the relationship between sperm morphology and motility.Molecular reproduction and development · 2020Review
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4 authors.
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Abstract
backgroundSexual selection continues after copulation via either sperm competition or cryptic female choice, and favors sperm traits that maximize sperm competitiveness. Both sperm swimming velocity and longevity are important determinants of the outcome of sperm competition. Theoretically, sperm morphology can influence sperm velocity at least in three different non-exclusive ways: (i) longer sperm may generate more propelling thrust, (ii) bigger midpieces may produce more energy, and/or (iii) larger flagella or mid-pieces relative to the head size may compensate for the drag forces around the head. A growing number of studies have investigated the relationship of sperm morphology with sperm performance, which remains equivocal at both the inter- and intra-specific levels. Here, we used House Sparrows to test the functional relationship between sperm morphology with sperm velocity and longevity. Based on a previous study showing that sperm swimming ability covaries with social rank, we predicted that -if a functional relationship exists-1) sperm morphology should differ across social ranks, and 2) correlations between sperm morphology and sperm velocity and/or sperm longevity should be constant across social ranks.
resultsWe found no differences in sperm morphology across social ranks. Moreover, we found that sperm morphology may be correlated with sperm velocity, but such relationship varied across social ranks. This result contradicts the hypothesis of a functional relationship between sperm morphology and sperm performance. Finally, after experimentally manipulating social ranks, we observed that relationships between sperm morphology and sperm velocity and/or sperm longevity disappeared or changed direction.
conclusionsWe suggest that in species with internal fertilization, while sperm morphology is likely constrained by the morphology of the female sperm storage organs, selection may act upon physiological traits that enhance sperm performance. Hence, these two selection forces could decouple sperm performance from sperm morphology.
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