Towards a resolution of the lek paradox

Genetic benefits in the shape of 'good genes' have been invoked to explain costly female choice in the absence of direct fitness benefits(1-3). Little genetic variance in fitness traits is expected, however, because direction al selection tends to drive beneficial alleles to fixation(4-6). There seem s to be little potential, therefore, for female choice to result in genetic benefits, giving rise to the 'lek paradox'(7-9). Nevertheless, evidence sh ows that genetic variance persists despite directional selection(10,11) and genetic benefits of female choice are frequently reported(12,13). A theore tical solution to the lek paradox has been proposed on the basis of two ass umptions(14): that traits are condition-dependent, and that condition shows high genetic variance. The observed genetic variability in sexual traits w ill be accounted for, because a proportion of the genetic variance in condi tion will be captured and expressed in the trait(14). Here we report result s from experiments showing that male courtship rate in the dung beetle Onth ophagus taurus is a condition-dependent trait that is preferred by females. More importantly, male condition has high genetic variance and is genetica lly correlated with courtship rate. Our results thereby represent a signifi cant step towards a resolution of the lek paradox.