Degree of anisogamy is unrelated to the intensity of sexual selection

Judit Mokos, István Scheuring, András Liker, Robert P. Freckleton, Tamás Székely

Research output: Contribution to journalArticlepeer-review

Abstract

Males and females often display different behaviours and, in the context of reproduction, these behaviours are labelled sex roles. The Darwin–Bateman paradigm argues that the root of these differences is anisogamy (i.e., differences in size and/or function of gametes between the sexes) that leads to biased sexual selection, and sex differences in parental care and body size. This evolutionary cascade, however, is contentious since some of the underpinning assumptions have been questioned. Here we investigate the relationships between anisogamy, sexual size dimorphism, sex difference in parental care and intensity of sexual selection using phylogenetic comparative analyses of 64 species from a wide range of animal taxa. The results question the first step of the Darwin–Bateman paradigm, as the extent of anisogamy does not appear to predict the intensity of sexual selection. The only significant predictor of sexual selection is the relative inputs of males and females into the care of offspring. We propose that ecological factors, life-history and demography have more substantial impacts on contemporary sex roles than the differences of gametic investments between the sexes.

Original languageEnglish
Article number19424
JournalScientific Reports
Volume11
Issue number1
Early online date30 Sep 2021
DOIs
Publication statusE-pub ahead of print - 30 Sep 2021

ASJC Scopus subject areas

  • General

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