Sexual imprinting and speciation in two Peromyscus species

1 Sexual isolation, a reproductive barrier, can prevent interbreeding between diverging 2 populations or species. Sexual isolation can have a clear genetic basis; however, it may also 3 result from learned mate preferences that form via sexual imprinting. Here, we demonstrate that 4 two sympatric sister species of mice—the white-footed mouse (Peromyscus leucopus) and its 5 closest relative, the cotton mouse (P. gossypinus)—hybridize only rarely in the wild despite co6 occurring in the same habitat and lack of any measurable intrinsic postzygotic barriers in 7 laboratory crosses. We present evidence that strong conspecific mate preferences in each species 8 form significant sexual isolation. We find that these mating preferences are learned in one 9 species but may be genetic in the other: P. gossypinus sexually imprints on its parents, but innate 10 biases or social learning affects mating preferences in P. leucopus. Our study demonstrates that 11 sexually imprinting contributes to reproductive isolation that reduces hybridization between 12 otherwise inter-fertile species, supporting a previously underappreciated role for learning in 13 mammalian speciation. 14 peer-reviewed) is the author/funder. All rights reserved. No reuse allowed without permission. The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/145243 doi: bioRxiv preprint first posted online Jun. 2, 2017;