Miyama Stag Beetle (Lucanus maculifemoratus) – Wildlife of Japan

Introduction

The Miyama stag beetle (Lucanus maculifemoratus) is one of Japan’s most iconic stag beetles, cherished by children and insect enthusiasts alike. Its impressive antler-like mandibles and preference for cooler mountain forests make it a symbol of Japan’s summer wildlife.

Appearance

This beetle is medium to large in size, ranging from 35–75 mm in length depending on sex and region. Males are instantly recognizable by their long, branching mandibles that resemble deer antlers, while females are smaller with shorter jaws. Their body color is typically dark brown with a bronze or greenish sheen, and they have a distinctive rough texture on their elytra.

A particularly notable feature is the pair of ear-like projections on the sides of the head, packed with strong muscles that allow the beetle to control its massive jaws with precision. In addition, fine golden hairs cover the thorax and elytra margins, catching the light and giving the beetle a beautiful shimmer.

Habitat

True to its name, the Miyama stag beetle inhabits mountainous and hilly forests, particularly broadleaf woods dominated by oak and beech. It is widely distributed across Honshu, Shikoku, and parts of Kyushu, but absent from Hokkaido. The species prefers higher altitudes compared to other common stag beetles.

Behavior

Males are highly territorial and often engage in fierce battles using their mandibles to compete for tree sap and females. They are primarily active at night, gathering around sap flows on oak trees during the summer months. Despite their intimidating appearance, they are harmless to humans.

Diet

Adult beetles feed on tree sap, especially from oak and chestnut trees. The larvae develop underground, feeding on decaying wood and playing an important role in forest ecosystems by recycling nutrients.

Reproduction

The breeding season occurs in mid-summer. After mating, females lay eggs in rotting wood or soil rich in decayed matter. The larval stage lasts two to three years before pupating and emerging as adults.

Conservation

While not considered endangered, the Miyama stag beetle faces pressure from habitat loss due to deforestation and over-collection by hobbyists. In some regions, populations are declining, making conservation of mountain forests crucial for their survival.

Author’s Impression

The Miyama stag beetle is truly one of a kind, with its unique ear-like projections and golden body hairs that set it apart from all other stag beetles. I personally love this species and observe it every year, but I have only once encountered a giant specimen over 70 mm. If you ever get the chance to search for them, I highly recommend aiming for a Miyama stag beetle over 70 mm—it’s an unforgettable experience.

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