Linking sperm length and velocity: the importance of intramale variation

Fitzpatrick, John L.; García‐González, Francisco; Evans, Jonathan P.

doi:10.1098/rsbl.2010.0231

Cited by 69 publications

(78 citation statements)

References 20 publications

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“…Marked phenotypic variation across sperm cells within a single ejaculate is ubiquitous, both in terms of sperm morphology [6][7][8] and performance [9]. However, sperm are generally considered products of the diploid paternal genome with no endogenous haploid gene expression, and sperm phenotype is thus thought not to reflect the haploid genome they carry [10].…”

Section: Introductionmentioning

confidence: 99%

Sperm variation within a single ejaculate affects offspring development in Atlantic salmon

et al. 2014

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It is generally believed that variation in sperm phenotype within a single ejaculate has no consequences for offspring performance, because sperm phenotypes are thought not to reflect sperm genotypes. We show that variation in individual sperm function within an ejaculate affects the performance of the resulting offspring in the Atlantic salmon Salmo salar. We experimentally manipulated the time between sperm activation and fertilization in order to select for sperm cohorts differing in longevity within single ejaculates of wild caught male salmon. We found that within-ejaculate variation in sperm longevity significantly affected offspring development and hence time until hatching. Whether these effects have a genetic or epigenetic basis needs to be further evaluated. However, our results provide experimental evidence for transgenerational effects of individual sperm function.

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Section: Introductionmentioning

confidence: 99%

Sperm variation within a single ejaculate affects offspring development in Atlantic salmon

et al. 2014

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“…Moreover, comparative studies show that sperm velocity is influenced by sperm size: longer sperm swim at higher speeds [5,8,9]. Though seemingly more controversial at the intraspecific level [10], recent studies also reveal a correlation between sperm length and velocity within species [11][12][13]. Thus, there is mounting evidence for a functional link between sperm structure and performance.…”

Section: Introductionmentioning

confidence: 99%

Evolution of sperm structure and energetics in passerine birds

et al. 2013

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Spermatozoa exhibit considerable interspecific variability in size and shape. Our understanding of the adaptive significance of this diversity, however, remains limited. Determining how variation in sperm structure translates into variation in sperm performance will contribute to our understanding of the evolutionary diversification of sperm form. Here, using data from passerine birds, we test the hypothesis that longer sperm swim faster because they have more available energy. We found that sperm with longer midpieces have higher levels of intracellular adenosine triphosphate (ATP), but that greater energy reserves do not translate into faster-swimming sperm. Additionally, we found that interspecific variation in sperm ATP concentration is not associated with the level of sperm competition faced by males. Finally, using Bayesian methods, we compared the evolutionary trajectories of sperm morphology and ATP content, and show that both traits have undergone directional evolutionary change. However, in contrast to recent suggestions in other taxa, we show that changes in ATP are unlikely to have preceded changes in morphology in passerine sperm. These results suggest that variable selective pressures are likely to have driven the evolution of sperm traits in different taxa, and highlight fundamental biological differences between taxa with internal and external fertilization, as well as those with and without sperm storage.

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“…Since closely related species, or males from the same species, show a much smaller degree of variation, the relationships between sperm swimming speed and size may only be uncovered when both dimensions and velocity are examined in the same sperm cells rather than each parameter being quantified in different subsamples from the same male (Fitzpatrick et al 2010). Besides methodological issues, different hypotheses have been proposed to explain which are the first evolutionary steps that lead to early increases in sperm swimming velocity.…”

Section: Introductionmentioning

confidence: 99%

Sperm competition differentially affects swimming velocity and size of spermatozoa from closely related muroid rodents: head first

Montoto¹,

Sánchez²,

Tourmente³

et al. 2011

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Sperm competition favours an increase in sperm swimming velocity that maximises the chances that sperm will reach the ova before rival sperm and fertilise. Comparative studies have shown that the increase in sperm swimming speed is associated with an increase in total sperm size. However, it is not known which are the first evolutionary steps that lead to increases in sperm swimming velocity. Using a group of closely related muroid rodents that differ in levels of sperm competition, we here test the hypothesis that subtle changes in sperm design may represent early evolutionary changes that could make sperm swim faster. Our findings show that as sperm competition increases so does sperm swimming speed. Sperm swimming velocity is associated with the size of all sperm components. However, levels of sperm competition are only related to an increase in sperm head area. Such increase is a consequence of an increase in the length of the sperm head, and also of the presence of an apical hook in some of the species studied. These findings suggest that the presence of a hook may modify the sperm head in such a way that would help sperm swim faster and may also be advantageous if sperm with larger heads are better able to attach to the epithelial cells lining the lower isthmus of the oviduct where sperm remain quiescent before the final race to reach the site of fertilisation.

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Linking sperm length and velocity: the importance of intramale variation

Cited by 69 publications

References 20 publications

Sperm variation within a single ejaculate affects offspring development in Atlantic salmon

Sperm variation within a single ejaculate affects offspring development in Atlantic salmon

Evolution of sperm structure and energetics in passerine birds

Sperm competition differentially affects swimming velocity and size of spermatozoa from closely related muroid rodents: head first

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