Japanese jewel beetle
Chrysochroa fulgidissima
— Where the name comes from
Chrysochroa is “golden-skinned”, from chrysós and chróa, the colour of the skin; fulgidissima is a Latin superlative, “most shining”. Two words overlapping in the same sense, and for once without exaggeration. The Japanese name, tamamushi, means “jewel insect”, and has entered the language as an adjective too: tamamushi-iro, “tamamushi-coloured”, is said of an ambiguous statement that changes meaning according to who hears it.
— Facts
- Group
- Insects · Insecta
- Order
- Beetles
- Habitat
- Broadleaf woodland, in the canopy on hot days
- Range
- Japan, Korea, eastern China, Taiwan
- Size
- 30–41 mm
- Diet
- Hackberry and zelkova leaves as an adult; dead wood as a larva
- Lifespan
- 1–2 years, nearly all as a larva
— Characteristics
- 01
The colour is not a pigment: it comes from the layered structure of the shell.
- 02
It shifts hue with the angle of view, from green to red.
- 03
The wing cases keep their colour for centuries after the insect dies.
— What sets it apart
The colour does not fade because it is not colour: the shell is made of twenty extremely thin layers that reflect light and interfere with one another, like a soap bubble, and as long as the structure holds so does the hue. That is why the treasury of the Hōryū-ji temple at Nara holds the Tamamushi Shrine, a seventh-century reliquary decorated with thousands of these wing cases: after thirteen hundred years the iridescent green is still legible, while the painted lacquers beside it have blackened. Physicists studying structural colour use it as a model for pigments that will not fade.
