Flagellum tapering and midpiece volume in songbird spermatozoa

Cramer, Emily R. A.; Grønstøl, Gaute; Lifjeld, Jan T.

doi:10.1002/jmor.21524

Cited by 3 publications

(2 citation statements)

References 84 publications

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“…The common nightingale had, at the same time, slightly wider midpiece than the thrush nightingale, suggesting that the common nightingale had an overall higher midpiece volume. This is consistent with recent study across multiple passerine species showing that sperm with longer midpiece tend to have also wider midpiece 73 . The tail length was also slightly longer in the common nightingale making the total flagellum length longer in this species.…”

Section: Discussionsupporting

confidence: 93%

Sperm morphology and performance in relation to postmating prezygotic isolation in two recently diverged passerine species

Poignet

Baránková

Reif

et al. 2022

Sci Rep

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Divergence in sperm phenotype and female reproductive environment may be a common source of postmating prezygotic (PMPZ) isolation between species. However, compared to other reproductive barriers it has received much less attention. In this study, we examined sperm morphology and velocity in two hybridizing passerine species, the common nightingale (Luscinia megarhynchos) and thrush nightingale (L. luscinia). In addition, we for the first time characterized a passerine female reproductive tract fluid proteome. We demonstrate that spermatozoa of the common nightingale have significantly longer and wider midpiece (proximal part of the flagellum containing mitochondria) and longer tail compared to spermatozoa of thrush nightingale. On the other hand, they have significantly shorter and narrower acrosome. Importantly, these differences did not have any effect on sperm velocity. Furthermore, the fluid from the reproductive tract of common nightingale females did not differentially affect velocity of conspecific and heterospecific sperm. Our results indicate that the observed changes in the flagellum and acrosome size are unlikely to contribute to PMPZ isolation through differential sperm velocity of conspecific and heterospecific sperm in the female reproductive tract. However, they could affect other postcopulatory processes, which might be involved in PMPZ isolation, such as sperm storage, longevity or sperm-egg interaction.

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Section: Discussionsupporting

confidence: 93%

Sperm morphology and performance in relation to postmating prezygotic isolation in two recently diverged passerine species

Poignet

Baránková

Reif

et al. 2022

Sci Rep

Self Cite

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show abstract

“…Also, our method is the same as the one used to measure swimming speed in passerine sperm, and we used the exact same equipment and observers as in some of the studies on passerines (e.g., Knief et al, 2017;Míčková et al, 2023;Opatová et al, 2016). Second, although the midpiece contains the mitochondria, midpiece volume rather than length might be relevant for sperm swimming speed (Cardullo & Baltz, 1991;Mendonca et al, 2018), but see Cramer et al (2022), or midpiece length might be associated with other sperm performance parameters such as longevity (which we did not measure). Third, it remains unclear whether oxidative phosphorylation in the midpiece is the primary source of energy for moving sperm (Turner, 2003).…”

Section: Relationship Between Sperm Swimming Speed and Morphologymentioning

confidence: 99%

Differences in sperm swimming speed and morphology between the three genetic morphs in the ruff sandpiper

Bulla

Küpper

Lank

et al. 2023

Preprint

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The ruff sandpiper Calidris pugnax is a Palearctic lekking shorebird with three genetic morphs determined by an autosomal inversion. Male morphs differ strikingly in body size, ornaments, endocrinology and mating behavior. Aggressive Independents represent the ancestral haplotype, semi-cooperative Satellites and female-mimicking Faeders the inverted haplotypes. Since one inversion breakpoint is homozygous lethal, the inverted haplotypes (Satellite and Faeder) cannot recombine and are expected to accumulate mutations. The inversion regions also harbor genes involved in spermatogenesis. However, it is unknown whether the genetic difference between the morphs also translate into differences in sperm traits. Here, we use a captive-bred population of ruffs to compare sperm velocity and morphology among the morphs. Faeder sperm moved the slowest, which is in line with expectations from mutation accumulation and the idea that Faeders might fare worse than Satellites, as Satellite haplotype arose through a rare recombination event that may have re-instated the function of sperm-related genes or helped to purge deleterious mutations. Against the expectation from mutation accumulation, sperm of Independents did not seem to be of highest quality, i.e., they were not the fastest nor the least variable, and they had the shortest tail and midpiece. Although the midpiece contains the energy-producing mitochondria, sperm midpiece length was not associated with sperm swimming speed. Instead, two of three velocity metrics were weakly positively associated with head length (absolute and relative). These results may relate to our observation that although ruff sperm morphologically resemble those of passerines, they generally appear to move differently, vibrating from side to side while slowly moving forward, rather than rotating while moving forwards. To conclude, the three genetically determined morphs showed only minor differences in sperm traits, and these differences were not clearly associated with variation in sperm velocity, indicating a low potential for the evolution of morph-specific sperm adaptations.

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Flagellum tapering and midpiece volume in songbird spermatozoa

Cramer

Grønstøl

Lifjeld

2022

Journal of Morphology

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In contrast to numerous studies on spermatozoa length, relatively little work focuses on the width of spermatozoa, and particularly the width of the midpiece and flagellum. In flagellated spermatozoa, the flagellum provides forward thrust while energy may be provided via mitochondria in the midpiece and/or through glycolysis along the flagellum itself. Longer flagella may be able to provide greater thrust but may also require stronger structural features and more or larger mitochondria to supply sufficient energy. Here, we use scanning electron microscopy to investigate the ultrastructure of spermatozoa from 55 passerine species in 26 taxonomic families in the Passerides infraorder. Our data confirm the qualitative observation that the flagellum tapers along its length, and we show that longer flagella are wider at the neck. This pattern is similar to mammals, and likely reflects the need for longer cells to be stronger against shearing forces. We further estimate the volume of the mitochondrial helix and show that it correlates well with midpiece length, supporting the use of midpiece length as a proxy for mitochondrial volume, at least in betweenspecies studies where midpiece length is highly variable. These results provide important context for understanding the evolutionary correlations among different sperm cell components and dimensions.

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Flagellum tapering and midpiece volume in songbird spermatozoa

Cited by 3 publications

References 84 publications

Sperm morphology and performance in relation to postmating prezygotic isolation in two recently diverged passerine species

Sperm morphology and performance in relation to postmating prezygotic isolation in two recently diverged passerine species

Differences in sperm swimming speed and morphology between the three genetic morphs in the ruff sandpiper

Flagellum tapering and midpiece volume in songbird spermatozoa

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