Structural Colours in Lepidopteran Scales

Photonic structures incorporated in lepidopteran scales are responsible for a very broad range of optical effects: iridescence, narrow-band reflection, large solid-angle scattering, polarisation effects, additive colour mixing and more. They have been the most investigated natural photonic structures for a long time. Such studies provide both understanding of the optical mechanisms and the biological functions behind these effects as well as inspiration for the design and development of novel photonic materials through a bioinspiration approach. In this chapter, research regarding structural colours in lepidopteran wing scales is reviewed through the classification of the related photonic structures. Selected examples of these structures are used to illustrate how such optical effects are brought about.