Bioclimatic data
The method of principal components was used to identify the influence of environmental variables on the sex ratios in each population. PCA was applied to sex ratios and climatic parameters. Climatic factors for the data matrix were retrieved from WorldClim (Fick and Hijmans 2017) and ENVIREM (Title and Bemmels 2018) and were designated as follows: Bio1, average mean temperature; Bio7, temperature annual range; Bio12, annual precipitation; Elev, elevation; and Arid, Aridity Index. We selected the climatic parameters by following their importance for the sex ratios in populations of gynodioecious plants. The values for each site were determined at a very high spatial resolution of 30 seconds (~1 km2). Close relationships (positive or negative) between climatic parameters and the frequency of females in populations with the main components were considered as the influence of various environmental variables on the variation in the frequency of females. An arcsine transformation of the females’ frequency in populations was performed before determining the main components.