The evolution of sperm morphometry in pheasants

Immler, Simone; Saint-Jalme, Michel; Lesobre, Loïc; Sorci, Gabriele; Roman, Y.; Birkhead, Tim R.

doi:10.1111/j.1420-9101.2007.01302.x

Cited by 39 publications

(51 citation statements)

References 67 publications

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“…Increases in sperm size in species with high levels of sperm competition have been found in 8 of these studies including such diverse taxa as birds, frogs, fish, butterflies, moths and nematodes. One study has not found such a relationship in pheasants (Immler et al, 2007b), while a negative relationship has been reported in fish (Stockley et al, 1997). Interestingly, a recent study on passerine birds has revealed that while among finches (family Fringillidae) there was a positive relationship between sperm competition and sperm length, among Old World warblers (family Sylviidae) the relation was negative.…”

Section: Sperm Size and Sperm Competitionmentioning

confidence: 90%

“…Second, in some taxa spermatozoa are stored in specialized organs in the female tract. In these cases, sperm size is often associated with the size of the sperm storage organ (Immler et al, 2007b;review in Snook, 2005). The use of an experimental approach in Drosophila has revealed that male fertilization success is determined by an interaction between sperm size and the size of the female sperm storage organ, so that when the female storage organ is long, long sperm are more successful, but there is no effect of sperm size when the female storage organ is short (Miller and Pitnick, 2002).…”

Section: Sperm Size and Sperm Competitionmentioning

confidence: 99%

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Implications of diversity in sperm size and function for sperm competition and fertility

Gomendio

Roldán²

2008

Int. J. Dev. Biol.

168

185

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Sperm competition is now recognised as a potent selective force shaping many male reproductive traits. While the influence of sperm competition on sperm number is widely accepted, its effects upon sperm size remain controversial. It had been traditionally assumed that there is a trade-off between sperm number and sperm size, so that an increase in sperm number would result in a decrease in sperm size, under conditions of sperm competition. Contrary to this prediction, we proposed some time ago that sperm competition favours an increase in sperm size, because longer sperm swim faster and are more likely to win the race to fertilize ova. Comparative studies between species show that in many taxa such a relationship exists, but the consequences of an increase in sperm size may vary between taxa depending on the environment in which spermatozoa have to compete. We present new evidence showing that in mammals longer sperm swim at higher speeds. We also show that mean swimming speed is highly correlated with maximum swimming speed, so even if the fastest swimming sperm are more likely to fertilize, both measures are informative. When individuals of the same species are compared, ratios between the dimensions of different sperm components, as well as the shape of the head, seem better at explaining sperm swimming velocity. Finally, we show that mean and maximum sperm swimming speed determine male fertility. Other studies have shown that in competitive contexts, males with faster swimming sperm have higher fertilization success. We conclude that the available evidence supports our original hypothesis.

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Section: Sperm Size and Sperm Competitionmentioning

confidence: 90%

Section: Sperm Size and Sperm Competitionmentioning

confidence: 99%

Implications of diversity in sperm size and function for sperm competition and fertility

Gomendio

Roldán²

2008

Int. J. Dev. Biol.

168

185

View full text Add to dashboard Cite

show abstract

“…Interestingly, morphometric sperm traits show a strong positive phenotypic correlation across species: in mammals for example, the size of the midpiece and the size of the flagellum are significantly positively correlated (r ¼ 0.44; [14,15]) as are head length and flagellum length (r ¼ 0.56; [15]). Similarly, in passerine birds and in pheasants, midpiece length and flagellum length are strongly positively correlated (passerine birds: r ¼ 0.84 [10], r ¼ 0.97 [16]; pheasants: r ¼ 0.78 [17]), suggesting that these traits show correlated evolution. However, the causes underlying this apparent correlated evolution are poorly understood.…”

Section: Introductionmentioning

confidence: 91%

“…Five sperm were measured for each male, which captures most of the intra-male variation, provides an accurate mean per male and allows detecting significant differences between males [17,24] (see the electronic supplementary material, table S3).…”

Section: (A) Datamentioning

confidence: 99%

Distinct evolutionary patterns of morphometric sperm traits in passerine birds

2012

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The striking diversity of sperm shape across the animal kingdom is still poorly understood. Postcopulatory sexual selection is an important factor driving the evolution of sperm size and shape. Interestingly, morphometric sperm traits, such as the length of the head, midpiece and flagellum, exhibit a strong positive phenotypic correlation across species. Here we used recently developed comparative methods to investigate how such phenotypic correlations between morphometric sperm traits may evolve. We compare allometric relationships and evolutionary trajectories of three morphometric sperm traits (length of head, midpiece and flagellum) in passerine birds. We show that these traits exhibit strong phenotypic correlations but that allometry varies across families. In addition, the evolutionary trajectories of the midpiece and flagellum are similar while the trajectory for head length differs. We discuss our findings in the light of three scenarios accounting for correlated trait evolution: (i) genetic correlation; (ii) concerted response to selection acting simultaneously on different traits; and (iii) phenotypic correlation between traits driven by mechanistic constraints owing to selection on sperm performance. Our results suggest that concerted response to selection is the most likely explanation for the phenotypic correlation between morphometric sperm traits.Keywords: trait coevolution; correlated traits; allometry; sperm morphometry; comparative methods INTRODUCTIONThe evolutionary causes and consequences of the remarkable diversity of spermatozoa are still poorly understood [1,2]. Morphometric sperm traits such as overall sperm length, midpiece length/volume and flagellum length (but not sperm head length) appear to be under postcopulatory sexual selection owing to varying risk of sperm competition (e.g. [3 -10]; but see [11]) and cryptic female choice [12,13]. Interestingly, morphometric sperm traits show a strong positive phenotypic correlation across species: in mammals for example, the size of the midpiece and the size of the flagellum are significantly positively correlated (r ¼ 0.44; [14,15] , suggesting that these traits show correlated evolution. However, the causes underlying this apparent correlated evolution are poorly understood. There are three non-exclusive scenarios that may lead to correlated evolution of two traits: (i) underlying genetic correlation [18], (ii) concerted response to selection acting simultaneously on different traits [19,20], and/or (iii) extrinsic functional or intrinsic mechanistic constraints

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“…Alternatively, sperm traits may evolve as an adaptation to the female reproductive tract environment [66,67], especially in species with sperm storage. In pheasants, Immler et al [68] showed that sperm velocity was negatively related to the duration of sperm storage (see also [4]), but independent of the risk of sperm competition. Given that sperm energetics probably influence sperm longevity, the effects of selection imposed by the female reproductive environment may confound a direct link between sperm competition and sperm ATP concentrations.…”

Section: (B) Sperm Competition and Sperm Atp Concentrationmentioning

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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The evolution of sperm morphometry in pheasants

Cited by 39 publications

References 67 publications

Implications of diversity in sperm size and function for sperm competition and fertility

Implications of diversity in sperm size and function for sperm competition and fertility

Distinct evolutionary patterns of morphometric sperm traits in passerine birds

Evolution of sperm structure and energetics in passerine birds

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