Chew's Long-jawed Stag Beetle

Chew's Long-jawed Stag Beetle key facts

Care level

Advanced

Lifespan

Adults 4-6 months (typical for the genus)

Size

Males 25.0-87.0 mm (wild record 87.0 mm; the captive record is 82.0 mm)

Diet

Beetle jelly (in the wild it visits flowers of herbaceous plants)

Temperature & Humidity

Cyclommatus above all dislike stale, humid air. Condensation inside the box is the worst case and shortens life, so keep the container somewhere cool and out of direct sun, and use newspaper or a well-perforated sheet under the lid for ventilation. Mist the substrate when the surface dries out.

Breeding & Egg-laying

Soak a soft log of oak or similar, about 10 cm across, for two hours to a day and strip the bark. Pack 3-5 cm of fine-grained fermented substrate hard in the base, lay the log on it and bury it completely. A female in good condition lays 20-30 eggs. Collect the larvae early, because they cannibalise each other if left too long.

Cohabitation

Keep singly. Hand pairing works once the beetles are mature and mating is easy; the female is far smaller than the male but pairs without trouble. The genus is fairly placid, but females are occasionally killed, so move the male to his own container once mating is confirmed.

Lifespan & Rearing Period

Adults live about four to six months, and larger males live longest. Larvae take three to six months for females and three to ten months for males. Feeding begins two to five weeks after emergence, so wait until the beetle is eating before pairing it.

Health & Notes

Fungus bottles are unsuitable and larvae die in ordinary mycelium. Pack fermented substrate to 80-90 per cent of the container and change it every two to three months. Rearing in wood is effective for males over 70 mm, though emergence comes two to six months later than on substrate. The larger the container, the larger the male that emerges.

About Chew's Long-jawed Stag Beetle

A long-jawed stag beetle native to Borneo, known for its gently curved mandibles and a wild record of 87.0mm — among the largest in its genus. Described in 1994, it's best suited to experienced keepers.

7 things to know before welcoming a Chew's Long-jawed Stag Beetle

1. 1Size Varies by Individual

   Adult males range widely in size, from 25.0mm to 87.0mm, with mandible length and curvature varying just as much between individuals. The wild record stands at 87.0mm, with a captive-bred record of 82.0mm, and larval-stage care plays a big role in reaching larger sizes.

2. 2Best Suited to Experienced Keepers

   This species is generally considered suitable for experienced keepers rather than beginners. It helps to have a working knowledge of temperature and humidity management and breeding setups before bringing one home.

3. 3Adult Lifespan of 4-6 Months

   As adults, these beetles typically live for around 4 to 6 months, a general guideline for the genus. Setting up a comfortable environment helps them stay active during that relatively short window.

4. 4Handle the Long Jaws with Care

   The long, curved mandibles call for careful handling and thoughtful housing choices. Keeping multiple beetles together isn't recommended, since the jaws can injure legs or bodies during encounters, so solitary housing is standard.

5. 5Warm, Humid Conditions Preferred

   As a native of Borneo's tropical environment, this species does best with stable temperature and humidity in captivity. Avoid extreme cold or dryness to help it live out its full lifespan.

6. 6A Relatively Recently Described Species

   The Chew's Long-jawed Stag Beetle was first described in 1994, making it relatively new among stag beetles. Care information is still being built up over time, so it helps to keep researching as you go.

7. 7Prepare Housing Before Arrival

   Before bringing one home, set up an enclosure, climbing branch, and substrate sized appropriately for an adult beetle. Because the mandibles are long, give it a roomy layout so it doesn't get caught on anything inside the case.

Frequently asked questions about Chew's Long-jawed Stag Beetle

Q.Is this species suitable for beginners?

A.This species is generally considered suitable for experienced keepers rather than beginners. It helps to build a foundation in temperature and humidity management and enclosure setup before bringing one home.

Q.How big do the mandibles get?

A.Adult males range from 25.0mm to 87.0mm, with a wild record of 87.0mm and a captive-bred record of 82.0mm. Mandible length varies considerably from one individual to the next.

Q.How long do adults live?

A.Adults typically live for around 4 to 6 months, a general guideline for the genus that can vary by individual. Providing a comfortable environment helps them make the most of that time.

Q.Can multiple beetles be kept together?

A.Because of the long mandibles, housing multiple beetles together carries a risk of injury from pinching, so solitary housing is generally recommended. If housed together, provide ample space and monitor them closely.

Q.What should I prepare before bringing one home?

A.It helps to have an appropriately sized enclosure, climbing branch, and substrate ready in advance. Since the mandibles are long, give it a roomy layout so it doesn't get caught on anything in a cramped case.

Useful tools for Chew's Long-jawed Stag Beetle care

Learn more about Chew's Long-jawed Stag Beetle in the encyclopedia

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