Evol Ecol Res 11: 759-770 (2009)     Full PDF if your library subscribes.

Male ornament variation in a sexually dimorphic seabird with variable male mating success

Stephanie G. Wright* and Donald C. Dearborn

Department of Biology and Program in Animal Behavior, Bucknell University, Lewisburg, Pennsylvania, USA

Correspondence: D.C. Dearborn, Department of Biology and Program in Animal Behavior, Bucknell University, Lewisburg, PA 17837, USA.
e-mail: don.dearborn@bucknell.edu

ABSTRACT

Questions: Are sex-specific ornaments necessarily under sexual selection? Could previous sexual selection have eliminated meaningful variation in male ornaments, as envisioned by the lek paradox?

Background: The lek paradox proposes that sexual selection on a trait can become limited by the availability of genetic variation. If prolonged directional selection leads to an exhaustion of genetic variation in male ornaments, selection would favour a corresponding decline in choosiness by females. Ornaments that have undergone this evolutionary process should have low phenotypic variation.

Organism: Great frigatebird, Fregata minor, whose male ornaments have been assumed to be sexually selected via female mate choice.

Methods: We compared morphological traits of males that did and did not succeed in attracting a mate. We also compared phenotypic variation of these traits versus phenotypic variation in (1) a behavioural trait shown to be sexually selected in this population, and (2) morphological traits shown to be sexually selected in other species.

Conclusion: We found no strong morphological predictors of male mating success and only partial evidence for the reduced phenotypic variation that would be predicted by the lek paradox. Specifically, phenotypic variation in male ornaments was lower than in the behavioural trait shown to be sexually selected in this population but was not low compared with ornaments shown to be sexually selected in other species.

Keywords: Fregata minor, lek paradox, ornaments, sexual selection, SWS1 opsin, ultraviolet.

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        © 2009 Donald C. Dearborn. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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