Wing patches on the night-flying male Dot-underwing moth, which appear to change in size with viewing angle due to nanosized ‘mirror’ scales, might attract the opposite sex.

Nocturnal butterflies and moths had been thought to rely almost exclusively on the release of pheromones for sexual communication.

Now, researchers at Australia’s Deakin University and colleagues have studied how different parts of the wings of male and female Eudocima materna interact with light.

Taking a close-up look at their wings using scanning electron microscopy, the team discovered stacked, nanosized mirror scales in three dark patches on the forewings of males. The patches appear to change in size due to the way the scales interact with dim light when the male vigorously vibrates its wings before flying towards a female.