Ocean acidification changes the male fitness landscape.
Nature Publishing Group
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Sperm competition is extremely common in many ecologically important marine taxa. Ocean acidification (OA) is driving rapid changes to the marine environments in which freely spawned sperm operate, yet the consequences of OA on sperm performance are poorly understood in the context of sperm competition. Here, we investigated the impacts of OA (+1000 μatm pCO2) on sperm competitiveness for the sea urchin Paracentrotus lividus. Males with faster sperm had greater competitive fertilisation success in both seawater conditions. Similarly, males with more motile sperm had greater sperm competitiveness, but only under current pCO2 levels. Under OA the strength of this association was significantly reduced and there were male sperm performance rank changes under OA, such that the best males in current conditions are not necessarily best under OA. Therefore OA will likely change the male fitness landscape, providing a mechanism by which environmental change alters the genetic landscape of marine species.
We acknowledge Catherina Artikis and Yueling Hao for their contributions to the molecular analysis. We thank the team at Exeter Biosciences for their help and support. A.L.C. was supported by a Natural Environment Research Council (NERC) PhD studentship to Exeter, and received additional funding from Exeter CLES PREF and a Santander Postgraduate Research Award (2014/2015). C.L. was supported by a UK-OARP NERC consortium grant NE/H017496/1 and a NERC UK Fellowship: NE/G014728/1. DRL was supported by funding from the United States, National Science Foundation (Grant DEB 1354272) which helped to fund the molecular analysis.
Scientific Reports, 2016, Vol. 6, Article no. 31250
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