• structural color;
  • multilayer;
  • variability;
  • RGB color;
  • Chrysochroa fulgidissima


The Japanese jewel beetle (Chrysochroa fulgidissima) is one of the beautiful beetles showing metallic green color that is kept over a millennium. This is a typical structural color resulting from a multilayer, frequently seen in insects. It was found that the elytra unexpectedly change the color from original green to blue or red by heating at 200°C or by immersing in bromoform for over 1 month. This variability implies that the multilayer consists of a thermosensitive porous material. The color change induced by heating was accompanied with elytron shrinkage; the sensitivity of the reflection peak was −0.6 nm/°C in 30–65°C. The porous structure was determined by positron annihilation lifetime spectroscopy; the averaged pore radius was around 0.25–0.30 nm, which is close to the size of the bromoform molecule. These features prove the thermosensitivity and porous structure of the multilayer although inunusual environments. J. Morphol., 2007. © 2007 Wiley-Liss, Inc.