In a study in tomorrow’s Nature we identify the cell cycle gene cortex as controlling major aspects of colour pattern variation in 3 species of Heliconius. A parallel paper out in the same issue identifies the same gene as controlling colour differences in the peppered moth.
While the butterflies use their patterns to deter predators by acting as warnings, the moths use them to camouflage themselves against their background.
The cortex gene is a rapidly evolving member of a conserved family of cell cycle regulators (the fizzy family). We think it is likely controlling the colour of scales on the wing through control of their developmental rate.
These findings are also featured in the Nature Podcast