Nature's miniature solar panels: the thermal properties of butterfly wing scales and their evolution

The wings of butterflies are covered in thousands of scales that have evolved to serve a range of functions including aerodynamic efficiency, colour signalling, camouflage, hydrophobicity and thermoregulation. Fundamental to these functions is the nanostructure of the scales. Interest in organisms' adaptation to their thermal

environment has grown in recent years as we try to understand and predict how organisms will respond to climate change. Butterflies are one of the best-studied insect groups with respect to thermal adaptation. They are also somewhat unusual in having large, scale-covered wings, which they use for thermoregulation, both to absorb

solar radiation to warm up and to radiate heat away from the body to cool down. While the importance of the wings for thermoregulation has been known for some time, only recently has the importance of the wing scale nanostructures begun to be appreciated.