Widespread loss of sexually selected traits: how the peacock lost its spots

Current and traditional research on sexual selection focuses largely on explaining the evolution (gain) of elaborate male traits and of female preferences for these traits. However, recent phylogenetic studies have revealed a surprising trend: that losses of these elaborate male traits are widespread and can be much more common than are gains. Furthermore, recent studies also show that female preferences for these male traits can be reduced, lost, or even reversed. These losses of traits and preferences could have important implications for competing models of sexual selection. Integrated phylogenetic, experimental and theoretical studies are needed to explain these unexpected patterns.