Unique Reflection Property Due to Bumpy Multilayer Structure in Elytra of Rhomborrhina unicolor

Various species of animals use microstructures in their bodies to produce brilliant colors called structural colors. In this study, we analyzed the glossy green structural color of Rhomborrhina unicolor (a coleoptera) using scanning transmission electron microscopy (STEM) and reflection spectroscopy. The reflector in the elytra of R. unicolor is composed of a bumpy multilayer whose tilting angle to the elytron surface is approximately 20 degrees, as revealed by STEM and reflection spectroscopy. This bumpiness broadens the reflection band. In other words, the green light is reflected over a broad range of angles to the elytron surface, which may be helpful in camouflage, conspecific recognition, and so forth. (C) 2010 The Japan Society of Applied Physics DOI: 10.1143/JJAP.49.047201