ABSTRACT
In some cases, the optical function of the structure may be a beneficial side effect of structures evolved for other purposes. e functions of some structures on beetles (order Coleoptera) and butterflies (order Lepidoptera), for example, may be more specifically evolved for thermal regulation, rather than display. Diffraction gratings prevalent among species of snakes, lizards, and certain beetles may contribute to improved movement through swamp or mud-based habitats, either through friction reduction or by providing additional support for forward motion in dense or compressed environments.2 Iridescent structures over dark pigments are often seen in bird wings near the tips of the flight feathers, contributing significantly to their robustness, whereas the blue iridescent multilayer structures in certain shade-growing plants, such as Begonia pavonina, seem to enable resistance to photodamage.4,20-22 Structural color can also be used by plants to entice pollinators to visit.4
