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

Nolwenn Fresneau, Ivett Pipoly, Dóra Gigler, András Kosztolányi, Tamás Székely, András Liker

Research output: Contribution to journalArticlepeer-review


Males and females often have different roles in reproduction, although the origin of these differences has 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 that reversed sex roles are associated with both male-skewed adult sex ratios and high breeding densities. Furthermore, phylogenetic path analyses provide general support for sex ratios driving sex role variations rather than being a consequence of sex roles. Together, these important results open future research directions by showing that different mating opportunities of males and females play a major role in generating the evolutionary diversity of sex roles, mating system, and parental care.

Original languageEnglish
Article numbere2321294121
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number22
Publication statusPublished - 28 May 2024

Data Availability Statement

Data used for the analyses are available on Dryad (doi:10.5061/dryad.pvmcvdntb) (106). All other data are included in the manuscript and/or SI Appendix


We thank the anonymous referees, as well as Marcus Feldman, May R. Berenbaum, and the PNAS Editorial Board, for their valuable comments, which significantly improved our manuscripts. We would also like to express our gratitude to Jose O. Valdebenito for his assistance in creating the consensus tree.


  • adult sex ratio
  • habitat productivity
  • mating system
  • parental care
  • sex-role reversal

ASJC Scopus subject areas

  • General

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