Colouration

Colouration refers to the colour and colour patterns observed in living organisms and in materials. In biology, colouration can arise from pigments, from structural colouration, or from a combination of both. Pigment-based colouration results from molecules that absorb certain wavelengths of light and reflect others. Common biological pigments include melanin (providing black to brown tones), carotenoids (reds, oranges, yellows), and anthocyanins (reds to blues). Pigments can be produced by the organism or derived from diet, and their abundance can vary with development, health, or environment.

Structural colouration is produced when micro- or nano-scale structures interact with light, causing interference, diffraction, or scattering. This can generate vivid blues and greens or iridescent effects that change with viewing angle. Structural colouration is common in birds, insects, and some fish, and explains features such as butterfly wing scales and the iridescence of certain beetles.

Colouration serves ecological and social roles. Camouflage and disruptive colouration help conceal organisms. Aposematic colouration warns predators of toxicity. Bright colours and pattern variation are used in courtship and mate selection. Colour can also influence thermoregulation by absorbing or reflecting solar radiation.

Colouration is influenced by genetics, hormones, diet, and environment. Natural selection can shape patterns that improve survival or reproduction, and rapid colour shifts can occur in response to changing conditions. In humans, dyes and pigments are used commercially in art, agriculture, and industry.

Study and measurement: Researchers examine colouration with spectrometry, imaging, and perceptual models to understand how colours are produced and how they are perceived by other animals or humans.