Credit: W. PIEL

Proc. R. Soc. B. doi:10.1098/rspb.2009.0182 (2009)

Biologists believe that some butterflies send mixed signals. Wings with brightly coloured topsides attract mates, for example, whereas camouflaged undersides protect against predators.

Jeffrey Oliver of Yale University and his colleagues compared the rates of wing-pattern evolution in 54 species of the genus Bicyclus (pictured, Bicyclus anynana). Because eyespots are evolving at different rates on the upper and lower surfaces of Bicyclus wings, the team concludes that markings on different parts of the wings are probably used for different purposes and suggest this separation of signals allows butterflies to be simultaneously attractive to mates and safe from predators.