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Ryukyu Lesser Stag Beetle
IntermediateDorcus amamianus nomurai
The subspecies of Dorcus amamianus found in the north of Okinawa Island. The body is a glossy black and the mandibles are short and strongly curved; long legs and tarsi suit life in the trees, and it is not as numerous as the mainland lesser stag.
Difficulty
Intermediate
Temperature
20〜28℃
Lifespan
6 months to 2 years as an adult
Size
Males 21.7-35.7mm, females 20-32mm
Humidity
60〜80%
Diet
Adults take sap of broadleaf trees and beetle jelly; larvae feed on soft rotten wood
About
The Ryukyu lesser stag is the subspecies of Dorcus amamianus that lives in the north of Okinawa Island, and is also known as the Okinawa lesser stag. Males measure 21.7-35.7 mm and females 20-32 mm, and the body is glossy black. The species as a whole is the smallest of Japan's lesser stag beetles and is divided into four subspecies spread from the Amami islands to the Yaeyama group. Despite its name, mitochondrial DNA shows it is not a close relative of the common Japanese lesser stag and has more in common with Dorcus montivagus. The mandibles are short and strongly curved and the legs and tarsi rather long, better suited to life in the trees than in hollows. Females show longitudinal striae on the elytra and a pair of weak swellings on the head, which separates them from the similar females of Rhaetulus recticornis. It lives in broadleaf forest, with adults active from late May to October and peaking from June to August, usually feeding on sap up in the trees. Females lay in rotten broadleaf wood along streams. The 2025 edition of BE-KUWA lists a captive record of 39.2 mm and a wild record of 36.3 mm.
Source: Wikipedia (CC BY-SA 4.0)
Lifespan of the Ryukyu Lesser Stag Beetle
The Ryukyu Lesser Stag Beetle lives 6 months to 2 years as an adult.
Size of the Ryukyu Lesser Stag Beetle
The Ryukyu Lesser Stag Beetle grows to Males 21.7-35.7mm, females 20-32mm.
Basic Info
Origin
Japan (northern Okinawa Island)
Lifespan
6 months to 2 years as an adult
Care Specifications
SolitaryBreeding: Moderate
Sources: Dorcus amamianus - Wikipedia (JA; ranges and sizes of the four subspecies, morphology, life cycle, lifespan, larval period) / GBIF species page for Dorcus amamianus nomurai Mizunuma, 1994, the subspecies of northern Okinawa Island / BE-KUWA Certified Breeding Records (Mushi-sha, FY2025 edition PDF, JA)
Breeding Records & Localities
Captive record (♂)
39.2 mm
Wild record (♂)
36.3 mm
Record source: BE-KUWA 2025 edition, captive records for medium and large Japanese stag beetles (Ryukyu lesser stag: captive 39.2 mm, Minoru Kanazawa, registered 2007; dream maximum 44 mm; wild 36.3 mm, Naoto Yoshida). The same edition's small-specimen table lists a captive 19.0 mm (2021) and a wild 21.7 mm (Tsuneyoshi Kizaki, 2009).
Notable localities
Northern Okinawa Island
Regional subspecies
- Dorcus amamianus amamianus — Amami-Oshima, Kakeromajima
- Dorcus amamianus kubotai — Tokunoshima
- Dorcus amamianus nomurai（This entry） — Northern Okinawa Island
- Dorcus amamianus yaeyamaensis — Iriomotejima
The Japanese Wikipedia also gives 39.2 mm (2007) as the captive maximum for this subspecies, matching the BE-KUWA record.
Generation codes
- WD
- Wild-caught
- WF1
- Offspring of a wild-caught female
- F1〜
- Captive generations (same locality)
References & Sources
Edited & verified by: BreederDirect editorial team
The taxonomic, regulatory, and husbandry data on this page are compiled and verified against the authoritative primary sources below.
Primary sources
- Wikipedia
- CITES Appendix (checklist.cites.org)
- Ministry of the Environment: list of National Endangered Species of Wild Fauna and Flora (only three Lucanidae are listed)
- e-Gov: Natural Parks Act (permission to take animals and plants in special zones)
- GBIF species page for Dorcus amamianus nomurai Mizunuma, 1994, the subspecies of northern Okinawa Island
- BE-KUWA Certified Breeding Records (Mushi-sha, FY2025 edition PDF, JA)
Taxonomy & Authority
Accepted name: Dorcus amamianus nomurai (Nomura, 1964)
Synonyms: Dorcus amamianus nomurai Mizunuma, 1994, Dorcus amamianus okinawanus
Authority databases: GBIF
Nomenclature follows global taxonomic authority databases.
Regulations & Conservation Status
Not CITES-listed
Domestic law: The subspecies is confined to the north of Okinawa Island, an area that includes Yambaru National Park (the villages of Kunigami, Ogimi and Higashi) and part of the World Natural Heritage site 'Amami-Oshima Island, Tokunoshima Island, Northern part of Okinawa Island, and Iriomote Island'. Inside a national park's special zones the Natural Parks Act requires permission to take animals or plants, and local authorities at collecting sites may restrict collecting by ordinance. The beetle is not designated as a National Endangered Species under the Act on Conservation of Endangered Species; among the Lucanidae only Neolucanus insulicola donan, Neolucanus okinawanus and Neolucanus protogenetivus hamaii are listed. What circulates is chiefly captive-bred stock, and anyone handling wild-caught beetles must check the rules for the collecting site.
Sources: CITES Appendix (checklist.cites.org) / Ministry of the Environment: list of National Endangered Species of Wild Fauna and Flora (only three Lucanidae are listed) / e-Gov: Natural Parks Act (permission to take animals and plants in special zones)
Regulations may change. Always verify the latest information with the relevant authorities.
Ryukyu Lesser Stag Beetle Listings
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