Iridescence in insects

Iridescence is when surfaces – such as the wings of butterflies – appear to change brightness and colour as the angle of view, or the angle of illumination, changes. The iridescent wings of Morpho butterflies are some of the best examples. The spectral reflectance changes with the angle of incidence – i.e. the viewing angle…

Iridescent emperor butterflies

Last year I came across these beautiful Indian purple emperors (Mimathyma ambica) at the, now famous site, for viewing mud puddling butterflies in northern Thailand. There is something about the sandy soil at this site in Chiang Dao, which attracts many butterflies from the surrounding forest. It is almost entirely males of each species which…