Eurycephalus Flat Stag Beetle

Eurycephalus Flat Stag Beetle key facts

Care level

Intermediate

Lifespan

Adults 1-3 years

Size

Males up to 78.6mm (wild record), females 30-35mm in captive examples

Temperature

18〜23℃

Diet

Beetle jelly (adults); kinshi bottles or fermented substrate (larvae)

Temperature & Humidity

Keep at 18-23C. Holding larvae at 18C to lengthen mandibles stalls their growth, so rear early instars at about 23C and lower the temperature once they have bulked up. Heat during the prepupal stage caused failed emergences in one batch.

Breeding & Egg-laying

Laying is as for other flat stags: firmly packed laying substrate, with logs optional. Expect about 20 larvae per set, with eggs visible within two weeks.

Cohabitation

House singly as with any flat stag. Keep cohabitation pairing short and remove the male once laying is confirmed.

Lifespan & Rearing Period

No species-specific adult lifespan is published. Larvae are slow to reach third instar and some take 18 months. They grow on Kawara or oyster kinshi or fermented substrate, but wander often.

Health & Notes

Captive males are mostly short-mandibled, and even 20g pupae often give only 60mm-class adults. Late bottle changes cause wandering and shrinkage.

About Eurycephalus Flat Stag Beetle

The Eurycephalus Flat Stag Beetle is a Java-endemic species with a glossy, broad-bodied build. Egg-laying is easy, but raising large specimens is challenging, making it best suited to intermediate keepers.

7 things to know before welcoming a Eurycephalus Flat Stag Beetle

1. 1Endemic to Java

   This species is endemic to the island of Java in Indonesia. It closely resembles the related Alcides Flat Stag Beetle, but can be distinguished by its broader body and stronger glossy sheen.

2. 2Short-Jawed Tendency

   Wild long-jawed individuals show off dramatically curved mandibles, but captive-bred beetles tend to develop the shorter-jawed form instead. Conditions during the larval stage are thought to influence which form emerges.

3. 3Slow Larval Growth

   Larvae grow at a relatively slow pace, so raising a large adult requires patience over the long term. Approach their care with a steady, unhurried mindset.

4. 4Egg-Laying Is Easy

   When it comes to breeding, getting females to lay eggs is fairly straightforward. Growing those larvae into large adults, however, calls for more experience and careful technique.

5. 5Intermediate Difficulty

   Overall, this species is considered suitable for intermediate keepers. Having some basic stag beetle keeping experience beforehand makes the process, from egg-laying through larval rearing, much smoother.

6. 6Temperature and Humidity Care

   Flat stag beetles can be sensitive to heat and dryness, so check the enclosure's location and moisture level regularly. Try to avoid sudden temperature swings as well.

7. 7Prepare Supplies First

   Before bringing one home, it helps to have the basics ready: an adult enclosure, insect substrate, a food dish, and climbing branches. If you're planning to breed, prepare a separate breeding case and egg-laying wood in advance too.

Frequently asked questions about Eurycephalus Flat Stag Beetle

Q.Where does the Eurycephalus Flat Stag Beetle live in the wild?

A.It is endemic to the island of Java in Indonesia. Individuals available domestically are mostly captive-bred by hobbyist breeders.

Q.How difficult is this species to keep?

A.It's considered suitable for intermediate keepers. Egg-laying is easy, but raising the larvae into large adults takes experience and technique.

Q.What determines the shape of the mandibles?

A.In the wild, the long-jawed form with dramatically curved mandibles is common, but captive individuals tend toward the short-jawed form. Conditions during the larval stage are thought to play a role.

Q.How large do adults typically grow?

A.Males have a wild record of up to 78.6mm, while captive-bred females typically measure around 30 to 35mm. Size varies considerably between individuals and depending on rearing conditions.

Q.Are there any legal restrictions on this species?

A.This species is not subject to CITES.

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