Revealing mechanisms of mating plug function under sexual selection



Stockley, Paula, Franco, Catarina, Claydon, Amy, Davidson, Amanda, Hammond, Dean ORCID: 0000-0002-6326-8739, Brownridge, Philip, Hurst, Jane ORCID: 0000-0002-3728-9624 and Beynon, Robert ORCID: 0000-0003-0857-495X
(2020) Revealing mechanisms of mating plug function under sexual selection. Proceedings of the National Academy of Sciences of USA, 117 (44). 27465 - 27473.

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Abstract

Mating plugs are produced by many sexually reproducing animals and are hypothesized to promote male fertilization success under promiscuous mating. However, tests of this hypothesis have been constrained by an inability to discriminate ejaculates of different males in direct competition. Here, we use stable isotope labeling in vivo and proteomics to achieve this in a promiscuous rodent, Myodes glareolus. We show that, although the first male’s plug is usually dislodged, it can be retained throughout the second male’s copulation. Retained plugs did not completely block rival sperm but did significantly limit their numbers. Differences in the number of each male’s sperm progressing through the female reproductive tract were also explained by natural variation in the size of mating plugs and reproductive accessory glands from which major plug proteins originate. Relative sperm numbers in turn predicted the relative fertilization success of rival males. Our application of stable isotopes to label ejaculates resolves a longstanding debate by revealing how rodent mating plugs promote fertilization success under competitive conditions. This approach opens new opportunities to reveal cryptic mechanisms of postcopulatory sexual selection among diverse animal taxa.

Item Type: Article
Uncontrolled Keywords: reproduction, ejaculates, sexual selection, proteomics, stable isotope, labeling
Depositing User: Symplectic Admin
Date Deposited: 07 Sep 2020 09:13
Last Modified: 07 Oct 2021 17:12
DOI: 10.1073/pnas.1920526117
Open Access URL: https://doi.org/10.1073/pnas.1920526117
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3099958