Operational Sex Ratio

Stephen M Shuster

Research output: Chapter in Book/Report/Conference proceedingChapter

5 Scopus citations


The Operational Sex Ratio, or OSR, first defined as 'the ratio of receptive females to potential mating males at any one time,' was designed to measure the level of competition for mates in animal populations. The apparent utility of the OSR as a proxy for sexual selection intensity established it as a standard metric for animal mating system research. However, the relationships between OSR and actual measures of sexual selection have proven inconsistent. Thus, while useful for characterizing known experimental populations, estimates of OSR are not equivalent to those for sexual selection and are unlikely account for observed patterns of evolutionary change.

Original languageEnglish (US)
Title of host publicationEncyclopedia of Evolutionary Biology
PublisherElsevier Inc.
Number of pages8
ISBN (Electronic)9780128004265
ISBN (Print)9780128000496
StatePublished - Apr 14 2016


  • Competition for mates
  • Mating systems
  • Potential reproductive rate
  • Sex ratio
  • Sexual selection

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences
  • General Biochemistry, Genetics and Molecular Biology


Dive into the research topics of 'Operational Sex Ratio'. Together they form a unique fingerprint.

Cite this