TY - JOUR IS - 1844 N1 - © 2016 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. TI - Postcopulatory sexual selection influences baculum evolution in primates and carnivores AV - public VL - 283 Y1 - 2016/12/14/ JF - Proceedings of the Royal Society B: Biological Sciences A1 - Opie, CF A1 - Brindle, M KW - Baculum; Postcopulatory sexual selection; Prolonged intromission; Primates; Carnivores; Bayesian phylogenetics N2 - The extreme morphological variability of the baculum across mammals is thought to be the result of sexual selection, particularly, high levels of postcopulatory selection. However, the evolutionary trajectory of the mammalian baculum is little studied and evidence for the adaptive function of the baculum has so far been elusive. Here we use Markov chain Monte Carlo methods implemented in a Bayesian phylogenetic framework to reconstruct baculum evolution across the mammalian class and investigate the rate of baculum length evolution within the primate order. We then test the effects of testes mass (postcopulatory sexual selection), polygamy, seasonal breeding and intromission duration on the baculum in primates and carnivores. The ancestral mammal did not have a baculum, but both ancestral primates and carnivores did. No relationship was found between testes mass and baculum length in either primates or carnivores. Intromission duration correlated with baculum presence over the course of primate evolution, and prolonged intromission predicts significantly longer bacula in extant primates and carnivores. Both polygamous and seasonal breeding systems predict significantly longer bacula in primates. These results suggest the baculum plays an important role in facilitating reproductive strategies in populations with high levels of postcopulatory sexual selection. ID - discovery1524876 UR - http://dx.doi.org/10.1098/rspb.2016.1736 ER -