Taiwanese Flat Stag Beetle

Taiwanese Flat Stag Beetle key facts

Care level

Intermediate

Lifespan

Adults 1-3 years

Size

Males 45-73.7 mm / females 30-35 mm (captive record 79.5 mm)

Temperature

20〜26℃

Diet

Tree sap, beetle jelly

Temperature & Humidity

Keep at about 20-26 C. Being subtropical Taiwanese stock, it must not be exposed to winter cold. Larvae prefer fairly moist substrate, so do not let it dry out.

Breeding & Egg-laying

Females lay in the buried base of dead broadleaf trees and under fallen logs, so use a set combining a log with fermented substrate. Eggs hatch in about a month and larvae prefer wood decayed by white-rot fungi. They grow in either substrate or fungus bottles.

Cohabitation

Flat stags are aggressive and their mandibles grip powerfully, so males can kill females. Keep them singly and limit pairing to a short supervised period.

Lifespan & Rearing Period

Adults live 1-3 years. The larval stage lasts one to two years, usually two; newly emerged adults stay inactive that year, overwinter in the pupal cell and begin activity in early summer of the following year.

Health & Notes

Released foreign flat stags hybridising with native subspecies and contaminating their genetics is a recognised problem in Japan. This subspecies is phylogenetically close to the Japanese ones, so the risk is high and captive stock must never be released.

About Taiwanese Flat Stag Beetle

A flat stag beetle subspecies from Taiwan and Green Island; males reach up to 73.7mm with thick, curved mandibles. Fairly calm-natured and rated intermediate difficulty to keep.

7 things to know before welcoming a Taiwanese Flat Stag Beetle

1. 1Handle the Mandibles with Care

   The Taiwanese Flat Stag Beetle has thick, short mandibles with a sharply curved tip that deliver a powerful pinch. Keep your fingers away from the mandibles' range of motion when handling it bare-handed.

2. 2Best Suited to Intermediate Keepers

   This species is generally considered suitable for intermediate-level keepers, requiring attention to temperature, humidity, and substrate condition. Anyone with some prior beetle-keeping experience should find it manageable.

3. 3Adults Live One to Three Years

   As an adult, this beetle typically lives one to three years — longer than many stag beetle species. That gives keepers extended time to observe its day-to-day behavior and form a real bond with it.

4. 4Choosing an Enclosure and Substrate

   Keep it in a well-ventilated enclosure lined with insect-keeping substrate. Substrate can harden if it dries out, so mist it lightly whenever the surface starts to look dry to maintain adequate moisture.

5. 5Insect Jelly Is the Staple Food

   Commercial insect jelly is the main food source; check it every few days and replace it as it's consumed. Fruit is also readily eaten, but it spoils quickly and can attract fruit flies, so jelly-based feeding is generally preferred.

6. 6Activity Slows in Cool Weather

   When temperatures drop, activity slows and the beetle tends to stay hidden and still. Sudden temperature swings are stressful, so place the enclosure away from direct sunlight and air conditioning or heating vents.

7. 7Prepare the Enclosure Before Arrival

   Before bringing one home, prepare an enclosure, substrate, insect jelly, and a climbing branch to prevent the beetle from getting stuck on its back. Deciding on a placement location — away from direct sun and high heat and humidity — in advance makes for a smoother settling-in period.

Frequently asked questions about Taiwanese Flat Stag Beetle

Q.Is the Taiwanese Flat Stag Beetle suitable for beginners?

A.It's generally considered an intermediate-level species, but if you build the habit of managing temperature, humidity, and feeding, it's a reasonable species to try even while you're still building beetle-keeping experience. Start by setting up a solid enclosure environment.

Q.How much do males and females differ in size?

A.Males typically measure 45–73.7mm and females 30–35mm, with males being larger and developing more pronounced mandibles. A captive-bred record of 79.5mm has also been reported for males.

Q.How long do they live?

A.As adults, they typically live around one to three years. That's relatively long for a stag beetle, giving keepers plenty of time to bond with them through daily care.

Q.Is it dangerous to be pinched by the mandibles?

A.The mandibles are thick, short, and sharply curved at the tip, delivering a strong pinch if you're caught. When handling one, keep your fingers clear of the mandibles' range of motion and pick it up from the side or rear of the body instead.

Q.Are there any legal restrictions on keeping this species?

A.The Taiwanese Flat Stag Beetle is not subject to CITES.

Useful tools for Taiwanese Flat Stag Beetle care

Learn more about Taiwanese Flat Stag Beetle in the encyclopedia

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