Traits and hidden states: is self-fertilization associated with rates of diversification across mating and sexual systems?
Reproductive biology is a key determinant of fitness. State-dependent speciation-extinction methods (SSEs) are often used to associate traits with patterns of diversification. Previously, SSEs have been used within families to investigate the hypothesis that selfing is an evolutionary "dead end." To the best of the authors knowledge, no study has looked across families, which would increase power to more generally test this hypothesis. Here, we examine the impact of 1) mating system and 2) sexual system on diversification across 18 phylogenetically diverse families. We also discuss how more recent advances in SSE models (i.e., "hidden state" and tree-only models) influence our interpretation of these patterns and evaluate how the relationship between mating and sexual systems can be leveraged to gain insight into the impact of reproductive biology on evolutionary outcomes. In this study, we find that the mating system as a trait does not better explain patterns of diversification when compared to null models, but the sexual system often does. We also find family-level heterogeneity in our results, which suggests conclusions drawn from studies on individual families may not be consistent with any broader trend.