Colouration

In the world of Insects colouration is of two types: physical (optical) and chemical.

PHYSICAL COLOURATION. This type of colouration is produced by the interference and refraction of light in the surface layers of the integument; these layers contain inclusions in the form of lamellae, rods, variously sculpted ridges, which make the colours change according to the angle of incidence of the light.

CHEMICAL COLOURATION. This colouration derives mainly from the presence of pigments of various kinds, very often combined with one another. Variation in colour is achieved not only through differences in chemical composition but also through uneven concentrations of the pigment granules. For example, when highly concentrated, yellow pigment gives an orange colour; when more diluted, the result is a bright yellow. Other factors may also play a part in the colouration of Insects, such as the chlorophyll of the plants that caterpillars and grasshoppers eat as food.