Fig. 6
The relationship between the sexual selection index and diversification rate. Bayesian parameter estimates were inferred using the 20-parameter multiple state speciation and extinction model for the sexual selection index—a multi-state character with values ranging from 0, corresponding to the absence of courtship, sexual dichromatism, and ornamentation, to 3, indicating the presence of all 3 traits. Estimates of trait-specific speciation rates (lambda); trait-specific extinction rates (mu); transition rates (q); and net diversification rates calculated as the difference between speciation (lambda) and extinction (mu) rates. The 95% credibility intervals are indicated as horizontal colored bars above the x axis. Mirrored trees illustrating the contrast in branch length between species with a sexual selection index of 0 (absence of courtship, dichromatism, and ornamentation) versus a sexual selection index of 3 (presence of all 3 traits). The mean branch lengths for species with a sexual selection index of 0 is 20.6 ± 14.8 mya, while that of species with a sexual selection index of 3 is 2.7 ± 1.8 mya (mean ± sd). Ancestral state reconstructions by stochastic character mapping. Phylogeny restricted to species scored for the absence/presence of courtship, dichromatism, and ornamentation (n = 79). Branch colors represent posterior probability densities of edge states based on 1000 stochastic character maps of each reconstruction
