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…

Shiny bronze beetle

I came across this attractive ground beetle in Galicia, Spain. It was quite large, over an inch long (at c. 27 mm), with an attractive bronze sheen (1). Its taxonomic name is Carabus (Ctenocarabus) melancholicus costatus Germar, 1824, and occurs in the northern half of the Iberian Peninsula (2). Further south in Spain, there are two other subspecies: R. m.…