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Dorcus rectus
The most common small stag beetle in Japan's woodlands. Hardy, overwinters as an adult and lives for years — an ideal beginner species.
The kokuwa stag beetle (Dorcus rectus) is a small lucanid distributed throughout Japan from Hokkaido to Kyushu, inhabiting lowland and low-mountain woodlands, and is one of the most commonly encountered species in the country. Males measure 17-54 mm and females 21-33 mm, with a glossy blackish-brown body; the male's mandibles are slender with a single inner tooth. It gathers at the sap of sawtooth and konara oaks, is nocturnal, and is attracted to lights. Its greatest appeal is its hardiness and longevity: it overwinters as an adult and not uncommonly lives two to three years. Tolerant of both heat and cold and requiring no special temperature control, it is the ideal entry species for stag beetle keeping. Breeding is easy, with eggs laid in rotten wood or fermented substrate and larvae reared on mat or fungal media. Its gentle temperament and calm movements also make it a beloved subject for children's observation projects.
Origin
lowland and low-mountain woodlands of Japan, from Hokkaido to Kyushu
Lifespan
Adult 1-3 years (overwinters as adult)
Size
Male 17-54mm / Female 21-33mm
Temperature
18〜28℃
Humidity
50〜70%
Beetle jelly, tree sap
Edited & verified by: br-choku editorial team
The taxonomic, regulatory, and husbandry data on this page are compiled and verified against the authoritative primary sources below.
Accepted name: Dorcus rectus Motschulsky, 1857
Nomenclature follows global taxonomic authority databases.
Plant Protection Act: 国産(在来)種のため、生体の輸入に関わる外来生物法の種類名証明書は不要。
在来種だが、飼育・購入した個体を野外に放すことは避けること。コクワガタは産地ごとに地域性があり(複数の島嶼亜種が知られる)、他産地・他亜種の個体を逃がすと地域の野生個体群との交雑・遺伝的撹乱を招く。
Regulations may change. Always verify the latest information with the relevant authorities.
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18-28°C year-round; tolerant of heat and cold
Overwinters as an adult; can live 2-3 years
Lays readily in rotten wood or fermented mat; easy to breed
Gentle and calm; good for observation
Found on oak sap and rotten wood from May to September
Beginner. This is a beginner-friendly species. No special equipment or experience is required, and it can be kept successfully with basic care setup.
The ideal temperature for Kokuwa Stag Beetle is 18〜28℃. Recommended humidity is 50〜70%. Avoid sudden temperature changes and maintain a stable environment.
The average lifespan of Kokuwa Stag Beetle is Adult 1-3 years (overwinters as adult). With proper care and nutrition, they can live a long and healthy life.
Kokuwa Stag Beetle typically reaches Male 17-54mm / Female 21-33mm as an adult. Size may vary depending on care conditions and individual genetics.
Kokuwa Stag Beetle feeds on: Beetle jelly, tree sap. Aim for a balanced diet with appropriate feeding frequency.
The price of Kokuwa Stag Beetle varies significantly depending on morph, size, and lineage. Check our market price page for the latest pricing information.
Last updated: June 25, 2026