Runaway evolution from male-male competition

Allen J. Moore, Joel W. McGlothlin, Jason B. Wolf

Research output: Contribution to journalArticlepeer-review


Wondrously elaborate weapons and displays that appear to be counter to ecological optima are widespread features of male contests for mates across the animal kingdom. To understand how such diverse traits evolve, here we develop a quantitative genetic model of sexual selection for a male signaling trait that mediates aggression in male-male contests and show that an honest indicator of aggression can generate selection on itself by altering the social environment. This can cause selection to accelerate as the trait is elaborated, leading to runaway evolution. Thus, an evolving source of selection provided by the social environment is the fundamental unifying feature of runaway sexual selection driven by either male-male competition or female mate choice. However, a key difference is that runaway driven by male-male competition requires signal honesty. Our model identifies simple conditions that provide clear, testable predictions for empirical studies using standard quantitative genetic methods.

Original languageEnglish
Pages (from-to)295-306
Number of pages12
JournalEcology Letters
Issue number2
Early online date16 Nov 2021
Publication statusPublished - 28 Feb 2022


  • aggression
  • honest signals
  • indirect genetic effects
  • male-male competition
  • quantitative genetics
  • runaway evolution
  • sexual selection
  • social evolution
  • weapons

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


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