Diversification under sexual selection: the relative roles of mate preference strength and the degree of divergence in mate preferences.
Bottom Line: To ask how this disparity in focus may affect the conclusions of evolutionary research, we relate the amount of diversification in mating displays to quantitative descriptions of the strength and the amount of divergence in mate preferences across a diverse set of case studies of mate choice.We find that display diversification is better explained by preference divergence rather than preference strength; the effect of the latter is more subtle, and is best revealed as an interaction with the former.Adopting this view will enhance tests of the relative role of natural and sexual selection in processes such as speciation.
Affiliation: Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA. email@example.comShow MeSH
Mentions: We further compared how Δt relates to Δp and preference strength in terms of the effect size of the relationships. We found that the effect sizes for the Δt∼Δp relationship were significantly greater than for the Δt∼preference strength relationship (Welch anova allowing for unequal variances: F1,8.9314 = 53.97, P < 0.0001; Fig. 5a). This pattern remained when we used the absolute value of the effect sizes (Welch anova: F1,9.892 = 9.89, P = 0.022). We also found that these effect sizes were influenced by the sample size of each case study, with smaller N case studies likely overestimating effect sizes (Fig. 5b). Across 8 case studies (conservatively excluding the panmictic cricket population), the correlation between N and the effect size for Δp was r = −0.89, P = 0.0031; for preference strength, it was r = −0.66, P = 0.073. Nevertheless, effect sizes remained consistently stronger for Δp than for preference strength (Fig. 5b). In short, we found that the effect sizes for the Δt∼Δp relationship were always strong and positive, whereas the effect sizes for the Δt∼preference strength relationship were either weakly positive or negative (Figs 4 and 5).
Affiliation: Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA. firstname.lastname@example.org