Pre- and post-copulatory traits working in concert: sexual dichromatism in passerines is associated with sperm morphology

Durrant, Kate L.; Reader, Tom; Symonds, Matthew R. E.

Abstract

Passerine birds produce costly traits under intense sexual selection, including elaborate sexually dichromatic plumage and sperm morphologies, to compete for fertilizations. Plumage and sperm traits vary markedly among species, but it is unknown if this reflects a trade-off between pre- and post-copulatory investment under strong sexual selection producing negative trait covariance, or variation in the strength of sexual selection among species producing positive covariance. Using phylogenetic regression, we analysed datasets describing plumage and sperm morphological traits for 278 passerine species. We found a significant positive relationship between sperm midpiece length and male plumage elaboration and sexual dichromatism. We did not find a relationship between plumage elaboration and testes mass. Our results do not support a trade-off between plumage and sperm traits, but may be indicative of variance among species in the strength of sexual selection to produce both brightly coloured plumage and costly sperm traits.

Citation

Durrant, K. L., Reader, T., & Symonds, M. R. E. (2020). Pre- and post-copulatory traits working in concert: sexual dichromatism in passerines is associated with sperm morphology. Biology Letters, 16(1), 20190568. https://doi.org/10.1098/rsbl.2019.0568

• Journal Article Type: Article
• Acceptance Date: Nov 27, 2019
• Online Publication Date: Jan 15, 2020
• Publication Date: Jan 15, 2020
• Deposit Date: Jan 20, 2020
• Publicly Available Date: Jan 21, 2020
• Journal: Biology letters
• Electronic ISSN: 1744-957X
• Publisher: The Royal Society
• Peer Reviewed: Peer Reviewed
• Volume: 16
• Issue: 1
• Article Number: 20190568
• Pages: 20190568
• DOI: https://doi.org/10.1098/rsbl.2019.0568
• Keywords: Sperm competition, Midpiece, Plumage coloration, Birds, Phylogenetic generalized least squares
• Public URL: https://nottingham-repository.worktribe.com/output/3753381
• Publisher URL: https://royalsocietypublishing.org/doi/10.1098/rsbl.2019.0568
• Additional Information: Received: 2019-08-27; Accepted: 2019-11-27; Published: 2020-01-15