R-code for mixed-model analysis of sex differences in mate responses (Figure 3C)

R-code using the nlme-package for the statistical test of sex differences illustrated in Figure 3C (Svensson et al. 2014). To compare male and female mate preferences in relation to local ecology we performed a mixed model with “Sex” (males and females) and “Population Ecology” (allopatry vs. sympatry) and their interaction (“Sex × Population Ecology”) as independent fixed factors, and “Population identity” as a random factor (nested within the fixed factor “Population Ecology”)(Table S2). By including “Population identity” as a random factor, we adjusted for the fact all our populations contributed with multiple individuals to the analysis and hence our data points (individual mate responses) are not entirely statistically independent.