Intrasexual competition underlies sexual selection on male breeding coloration in the orangethroat darter, Etheostoma spectabile.

Muchu Zhou,Rebecca C Fuller

doi:10.1002/ece3.2136

Abstract

Elaborate, sexually dimorphic traits are widely thought to evolve under sexual selection through female preference, male–male competition, or both. The orangethroat darter (Etheostoma spectabile) is a sexually dichromatic fish in which females exhibit no preferences for male size or coloration. We tested whether these traits affect individual reproductive success in E. spectabile when multiple males are allowed to freely compete for a female. The quality and quantity of male coloration were associated with greater success in maintaining access to the female and in spawning as the primary male (first male to participate). On the other hand, sneaking behavior showed little correlation with coloration. Male breeding coloration in E. spectabile may therefore demonstrate how intrasexual competition can be a predominant factor underlying the evolution of male ornaments.

Highlights

Sexual selection theory, as originated by Darwin (1871), proposes that conspicuous male traits can evolve if they improve mating success through attractiveness to females, usefulness in competition with other males, or both
Male–male competition has been proposed to be more effective than female preferences in promoting the elaboration of male ornaments: as variation in an honest signal of male quality need not rely on genetic variation and can be maintained in the face of ongoing selection, the signal should a 2016 The Authors
Ecology and Evolution published by John Wiley & Sons Ltd

Summary

Introduction

As originated by Darwin (1871), proposes that conspicuous male traits can evolve if they improve mating success through attractiveness to females, usefulness in competition with other males, or both. Conspicuous male traits may be favored through intrasexual selection if they enable males to remotely evaluate rivals and avoid the cost of fighting unnecessary battles with mismatched opponents (Maynard Smith and Parker 1976; Rohwer 1982; Maynard Smith and Brown 1986). In this capacity, male ornaments should communicate relevant attributes such as size, condition, or fighting ability (Parker 1974; Zahavi 1977, 1981).

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