Kin-suji kogane (Mimela holosericea) – Wildlife of Japan
Introduction
The Kin-suji kogane (Mimela holosericea) is a rarely seen scarab beetle found in Japan. It has a metallic green body with slender golden ridges that sparkle like a tiny jewel. Beetle enthusiasts love this species; however, many aspects of its ecology remain unclear.
Appearance
This beetle reaches about 16–20 mm in length and shows a metallic green body that can slightly vary in shade. Several raised ridges run along the elytra, and the central one often looks like a thin golden stripe. In addition, the punctured surface between the ridges creates a very fine texture. Its legs are yellowish to reddish-brown, while the underside frequently shines with a copper to violet tint.
Habitat & Distribution
Kin-suji kogane belongs to the family Scarabaeidae, subfamily Rutelinae. It occurs in mountainous areas from Hokkaido through Honshu and Shikoku to Kyushu. It prefers cool and moist forests, especially where conifers grow. Even though it has a wide distribution, people only encounter it locally and not very often.
Behavior
Adults appear mainly in summer, especially around July and August. They are active at night and often fly to lights in mountain areas. During the day, they hide on vegetation or tree trunks and stay still until evening comes.
Diet
Adults feed on leaves or needles of trees they live around. In the same way, larvae grow underground and feed on plant roots. Fortunately, this species remains uncommon, so its impact on forests is rarely noticeable.
Reproduction
Females lay their eggs in soil, and larvae develop underground before pupating. Researchers still do not fully understand the life cycle in wild conditions. It may vary depending on temperature and habitat.
Conservation
The Kin-suji kogane is not protected nationwide; however, some regions treat it as a rare species. Protecting healthy mountain forests will help conserve its local populations.
Author’s Impression
I remember how hard I worked to find this beetle myself. It takes off right after dark, so checking street lamps or other lights in the early evening often helps. With a bit of luck, you might see its beautiful, shimmering form.
