A dominant allele controls development into female mimic male and diminutive female ruffs

Abstract

Maintaining polymorphisms for genes with effects of ecological significance may involve conflicting selection in males and females. We present data from a captive population of ruffs (Philomachus pugnax) showing that a dominant allele controls development into both small, 'female mimic' males ('faeders'), and a previously undescribed class of small 'female faeders'. Most male ruffs have elaborate breeding plumage and display behaviour, but 0.5-1.5% are faeders,which lack both. Females froma captive population previously lacking faederswere bredwith two founder faedermales and their faeder sons. The faeders' offspring had a quadrimodal size distribution comprising normal-sized males and females, faeders and atypically small females. By contrast, ornamentedmales fathered only normal-sizedoffspring.We conclude that both founding faeders were heterozygous for a faeder allele absent from the original population. This allele is dominant to previously described genes that determine development into independent versus satellite ornamented males. Unlike those genes, the faeder allele is clearly expressed in females. Small body size is a component of themale faedermating strategy, but provides no obvious benefit to females. Bisexual expression of the gene provides the opportunity to quantify the strength of sexually antagonistic selection on a Mendelian trait. © 2013 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0/, which permits unrestricted use, provided the original author and source are credited.