Data from: Sperm head morphology is associated with sperm swimming speed: a comparative study of songbirds using electron microscopy
Støstad, Hanna Nyborg, University of Oslo
Johnsen, Arild, University of Oslo
Lifjeld, Jan Terje, University of Oslo
Rowe, Melissah, University of Oslo
Published Jul 09, 2018 on Dryad.
Cite this dataset
Støstad, Hanna Nyborg; Johnsen, Arild; Lifjeld, Jan Terje; Rowe, Melissah (2018). Data from: Sperm head morphology is associated with sperm swimming speed: a comparative study of songbirds using electron microscopy [Dataset]. Dryad. https://doi.org/10.5061/dryad.341kj02
Sperm exhibit extraordinary levels of morphological diversification across the animal kingdom. In songbirds, sperm have a helically shaped head incorporating a distinct acrosomal membrane or ‘helical keel’, the form and extent of which varies across species. The functional significance of this helical shape, however, remains unknown. Using scanning electron microscopy, we quantified inter- and intra-specific variation in sperm head morphology across 36 songbird species (Passeriformes: Passerida). Using phylogenetic comparative methods, we investigated the relationship between sperm head morphology and both sperm swimming speed and the frequency of extra-pair young (EPY). We found that species whose sperm had a relatively more pronounced helical form (i.e. long acrosome, short nucleus, wide helical membrane, and a more pronounced waveform along the sperm head ‘core’) had faster-swimming sperm. We found no evidence of a relationship between inter-specific variation in sperm head morphology and EPY, although we did find that among- and within-male variation in sperm head traits were negatively correlated with EPY. Applying principles of fluid mechanics, we discuss how the helical form of the sperm head may influence swimming speed, and suggest that further studies considering aspects of sperm morphology beyond sperm length are needed to improve our understanding of sperm structure-function relationships.
Raw data for 2289 individuals of songbird
Individual data points for each sperm cell (used to create the species mean values), as well as accession numbers for the sperm bank at the Natural History Museum in Oslo.