Data from: Colour ornamentation in the blue tit: quantitative genetic (co)variances across sexes

Although secondary sexual traits are commonly more developed in males than
females, in many animal species females also display elaborate ornaments
or weaponry. Indirect selection on correlated traits in males and/or
direct sexual or social selection in females are hypothesized to drive the
evolution and maintenance of female ornaments. Yet, the relative roles of
these evolutionary processes remain unidentified, because little is known
about the genetic correlation that might exist between the ornaments of
both sexes, and few estimates of sex-specific autosomal or sex-linked
genetic variances are available. In this study, we used two wild blue tit
populations with 9 years of measurements on two colour ornaments: one
structurally based (blue crown) and one carotenoid based (yellow chest).
We found significant autosomal heritability for the chromatic part of the
structurally based colouration in both sexes, whereas carotenoid chroma
was heritable only in males, and the achromatic part of both colour
patches was mostly non heritable. Power limitations, which are probably
common among most data sets collected so far in wild populations,
prevented estimation of sex-linked genetic variance. Bivariate analyses
revealed very strong cross-sex genetic correlations in all heritable
traits, although the strength of these correlations was not related to the
level of sexual dimorphism. In total, our results suggest that males and
females share a majority of their genetic variation underlying colour
ornamentation, and hence the evolution of these sex-specific traits may
depend greatly on correlated responses to selection in the opposite sex.