The Scales on Moths and Butterflies
The wings, head parts of thorax and abdomen of the insect order Lepidoptera (moths and butterflies) are covered with minute scales. It is from this feature that the order ‘Lepidoptera’ (scale wing) derives its name. Most scales are lamellar, or blade-like and attached with a pedicel, while other forms may be hair-like or specialized as secondary sexual characteristics.
The lumen or surface of the lamella, has a complex structure. It gives color either by colored pigments that it contains, or through structural coloration with mechanisms that include photonic crystals and diffraction gratings.
Scales provide functions including insulation, thermoregulation, producing pheromones (in males only), and aiding gliding flight, but the most important is the large diversity of vivid or indistinct patterns they provide, which help the organism protect itself by camouflage or mimicry, and which act as signals to other animals including rivals and potential mates.
images: T - (photo by Jan Homann)
B - electron microscopic images of the wing scales of European Peacock (Inachis io), 50x, 200x, 1000x, and 5000x (images: Secret Disc | Wiki)