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Unifying cornerstones of sexual selection: operational sex ratio, Bateman gradient and the scope for competitive investment
Author(s) -
Kokko Hanna,
Klug Hope,
Jennions Michael D.
Publication year - 2012
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1111/j.1461-0248.2012.01859.x
Subject(s) - sexual selection , operational sex ratio , selection (genetic algorithm) , scope (computer science) , mating , biology , variation (astronomy) , ecology , reproductive success , mating system , investment (military) , mate choice , evolutionary biology , computer science , population , demography , artificial intelligence , sociology , physics , politics , astrophysics , law , political science , programming language
What explains variation in the strength of sexual selection across species, populations or differences between the sexes? Here, we show that unifying two well‐known lines of thinking provides the necessary conceptual framework to account for variation in sexual selection. The Bateman gradient and the operational sex ratio ( OSR ) are incomplete in complementary ways: the former describes the fitness gain per mating and the latter the potential difficulty of achieving it. We combine this insight with an analysis of the scope for sexually selected traits to spread despite naturally selected costs. We explain why the OSR sometimes does not affect the strength of sexual selection. An explanation of sexual selection becomes more logical when a long ‘dry time’ (‘time out’, recovery after mating due to e.g. parental care) is understood to reduce the expected time to the next mating when in the mating pool (i.e. available to mate again). This implies weaker selection to shorten the wait. An integrative view of sexual selection combines an understanding of the origin of OSR biases with how they are reflected in the Bateman gradient, and how this can produce selection for mate acquisition traits despite naturally selected costs.