The evolution of sex roles: The importance of ecology and social environment

Males and females often have different roles in reproduction, although the origin of these differences have remained controversial. Explaining the enigmatic reversed sex roles where males sacrifice their mating potential and provide full parental care is a particularly long-standing challenge in evolutionary biology. While most studies focused on ecological factors as the drivers of sex roles, recent research highlights the significance of social factors such as the adult sex ratio. To disentangle these propositions, here we investigate the additive and interactive effects of several ecological and social factors on sex role variation using shorebirds (sandpipers, plovers and allies) as model organisms that provide the full spectrum of sex role variation including some of the best known examples of sex role reversal. Our results consistently show that social factors play a prominent role in driving sex roles. Importantly, we show for the first time that reversed sex roles are associated..., All data were collected from published literature or open databases. We extensively searched the primary literature reporting the behavioral, demographic, and ecological variables used in this study through Web of Knowledge and Google Scholar. We used the keywords ‘shorebird’, ‘wader’, or the English and Latin name of species in combination with ‘sex ratio’, ‘sex role’, ‘mating system’, ‘polygamy’, ‘parental care’, ‘breeding’, or ‘population monitoring’. We also attempted to locate and screen-specific publication on shorebirds not available through the above databases (e.g., annual population reports, taxon specialists' group reports). First, because ASR was usually the limiting information, we searched for data on this variable to update and extend the dataset used in Liker et al. Nature (2013). Then, for the species with ASR estimates, we also screened the sources for other variables (mating system, parental care, hatching success, breeding density, see below). Data collection was con..., , # Data from: The evolution of sex roles: The importance of ecology and social environment [https://doi.org/10.5061/dryad.pvmcvdntb](https://doi.org/10.5061/dryad.pvmcvdntb) ## Description of the data and file structure **DataSpeciesLevel:** Species: Species latin name Phylo: Species latin name for the phylogenetic tree (some changed since) Latitude: Latitude (Average of the latitude of the population used for NDVI) NHatching_success: Number of population used for Hatching success NASR: Number of population used for ASR (Adult Sex Ratio) NDensity: Number of population used for Density NNDVI: Number of population used for NDVI (Normalized difference vegetation index) ParentalCareBias: Parental care bias species specific ParentalCareDurationBias: Parental care Duration bias species specific PolygamyFrequencyBias: polygamy frequency bias species specific - NA means that no data were found in the literature for this species PolygamyScoreBias: polygamy score bias species specifi...