ANTIREFLECTIVE NANOPROTUBERANCE ARRAY IN THE TRANSPARENT WING OF A HAWKMOTH, CEPHONODES HYLAS

A transparent wing of a hawkmoth, Cephonodes hylas, has a highly order ed array of nanosized protuberances in its surface. This protuberance array has almost the same morphology as that of the ''corneal nipple a rray'', which is suggested to function as an antireflective device to light, using a scaled model experiment, a theoretical calculation, and a comparative way. For the direct study of the function of this protu berance array, we prepared an artificial wing without protuberances an d compared it with an intact one with protuberances. Directly measurin g the light reflectance spectra of the intact wing and the artificial one, we demonstrated that the nanocomposite in the Cephopnodes wing de creases the light reflectance by the wing into 29-48% in the broad wav elength range. This antireflective effect is also showed by the color difference between the wings, coated by gold, with and without protube rances.