Acknowledgements

We thank Karen Sullam for helpful discussions related to project design and John Endler, Caryl Haskins, and David Reznick for initiating the original guppy introduction experiments that made this work possible. We also thank Kevin Dougherty and Lukas Bell-Dereske for assistance with laboratory and bioinformatic analyses and Nick Haddad, David Reznick, Joe Travis, and the Evans Lab for comments on earlier versions of this manuscript. We further thank David Reznick and his co-PIs from National Science Foundation Frontiers in Integrative Biological Research grant EF-0623632 for their support and intellectual contribution to our work. Funding was provided by Michigan State University and an NSF FSML grant (1722621) to SEE and SWF, Prociência UERJ and CNPq grant (308261/2017-8) to EZ and CAPES scholarship to JRA. Animal care and experimental procedures were approved by Colorado State University’s Institutional Animal Care and Use Committee (protocol no.12-3818A) and by the Fisheries division of Trinidad’s Ministry of Food Production, Land and Marine Affairs. This is Kellogg Biological Station contribution number 2173.