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Goto Flat Stag Beetle
IntermediateDorcus titanus karasuyamai
A subspecies of Dorcus titanus from the Goto Islands, Nagasaki. Its long mandibles are close to the Tsushima form but slightly stouter; wild males reach the high 70s and captive males 82 mm, a large island subspecies.
Difficulty
Intermediate
Temperature
20〜26℃
Lifespan
Adults 1-3 years
Size
Males 50-82 mm (including captive; wild up to 78.5 mm) / females 25-38 mm
Humidity
60〜80%
Diet
Tree sap, beetle jelly
About
The Goto flat stag (Dorcus titanus karasuyamai) is a subspecies of Dorcus titanus from the Goto Islands of Nagasaki, described in 1999. Males measure 50-82 mm and females 25-38 mm. The BE-KUWA captive record is 82.0 mm (2020) and the wild record 78.5 mm. Together with the Tsushima and Iki forms it belongs to the long-jawed group of the islands north-west of Kyushu, with body and mandibles slightly stouter than the Tsushima form. Mitochondrial DNA studies show natural mixing of the Tsushima lineage into northern Kyushu flat stags, and the Tsushima, Iki and Goto subspecies are close to that lineage. Ecology matches other flat stags: it gathers at sap in broadleaf forest, is nocturnal and hides in hollows. Females lay in the buried base of dead trees or under fallen logs; larvae take 1-2 years and adults live 1-3 years. At 20-26 C with logs and fermented substrate it breeds without difficulty. It is very aggressive and males often kill females, so keep singly except for pairing. To protect the native Goto population, never release captive beetles.
Source: Wikipedia (CC BY-SA 4.0)
Lifespan of the Goto Flat Stag Beetle
The Goto Flat Stag Beetle lives Adults 1-3 years.
Size of the Goto Flat Stag Beetle
The Goto Flat Stag Beetle grows to Males 50-82 mm (including captive; wild up to 78.5 mm) / females 25-38 mm.
Temperature & humidity for the Goto Flat Stag Beetle
The ideal temperature for the Goto Flat Stag Beetle is 20〜26℃.
Basic Info
Origin
Japan (Goto Islands, Nagasaki)
Care Specifications
AggressiveSolitaryBreeding: Easy
Sources: beetlebreeding.ch - The Breeding/Rearing of Dorcus titanus palawanicus by Kay (species-level guidance for D. titanus) / Dorcus titanus - Wikipedia (JA)
Breeding Records & Localities
Captive record (♂)
82 mm
Wild record (♂)
78.5 mm
Record source: BE-KUWA 2025 edition (Goto flat stag, captive 82.0 mm, 今岡司 2020 / wild 78.5 mm, 川原洋; projected maximum 93 mm)
Notable localities
Goto Islands (Nagasaki)
Regional subspecies
- Dorcus titanus karasuyamai — Goto Islands
A large subspecies of the islands north-west of Kyushu alongside Tsushima and Iki; differs only slightly from Tsushima stock.
Generation codes
- WD
- Wild-caught
- WF1
- Offspring of a wild-caught female
- F1〜
- Captive generations (same locality)
- CBF1
- Cross-locality captive-bred (reset)
Sources: BE-KUWA Certified Breeding Records (Mushi-sha, FY2025 edition PDF, JA) / Dorcus titanus - Wikipedia (JA)
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.
Taxonomy & Authority
Accepted name: Dorcus titanus karasuyamai Baba, 1999
Synonyms: Serrognathus titanus karasuyamai
Authority databases: GBIF
Nomenclature follows global taxonomic authority databases.
Regulations & Conservation Status
Not CITES-listed
Sources: CITES Appendix (checklist.cites.org)
Regulations may change. Always verify the latest information with the relevant authorities.
Goto Flat Stag Beetle Listings
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