In the application of game theory to evolutionary studies, moves in the game that cannot be beaten; i.e. traits or combinations of traits cannot be replaced by any invading mutant. Evolutionary stable strategy theory has proved very useful in the analysis of certain types of animal behaviour.
http://www.pbs.org/wgbh/evolution/library/06/2/l_062_03.html Information about John Maynard Smith, proposer of the evolutionary stable strategy.
Subjects: Ecology and Conservation — Zoology and Animal Sciences.