Kumejima Saw Stag Beetle

Kumejima Saw Stag Beetle key facts

Care level

Intermediate

Lifespan

Adults live two to three months in the wild

Size

Males 25-65.9 mm (including captive; the wild record is 64.4 mm) / females 24.5-31.5 mm

Diet

Sap of broadleaf trees such as Mallotus, Machilus and Castanopsis; beetle jelly

Temperature & Humidity

Although it comes from subtropical islands, keep it like the mainland Japanese saw stag. Avoid extreme cold in winter and keep the substrate moist enough to clump when squeezed. Larval substrate does best kept on the damp side.

Breeding & Egg-laying

She lays in substrate, but along the walls and floor of the box or against a log rather than in the middle of it. Pack black soil or fully fermented fine substrate firmly. Eggs hatch in about a month and larvae take one to two years. Slightly damp fermented substrate suits them best; fungus bottles work but offer little advantage.

Cohabitation

Males are very aggressive: where the mainland saw stag mostly postures, this group grabs straight away. Females are often killed during pairing, so keep the beetles singly, house them together only a few days and separate them once mating is seen.

Lifespan & Rearing Period

Adults live two to three months in the wild. They fly from mid-June to early September; the larva builds a pupal cell in spring, pupates in about a month and emerges about a month later. In captivity beetles that emerge by August become active after some two months, while later ones usually stay dormant even under temperature control.

Health & Notes

Males of this group cannot chew an exit hole through wood, so the larva usually leaves the log and builds its pupal cell in the soil; give it a deep layer of substrate. The subspecies are separated island by island, so never release captive beetles or cross stock from different localities.

About Kumejima Saw Stag Beetle

Kumejima Saw Stag Beetle, a Kume Island-only subspecies of the Amami Saw Stag Beetle, known for its thick, curved mandibles and dark reddish-brown to black body. Learn about its care difficulty, size, and lifespan.

7 things to know before welcoming a Kumejima Saw Stag Beetle

1. 1Watch the Temperature

   As an intermediate-level species to keep, this beetle needs stable temperature and humidity without extremes of heat or dryness. Sudden temperature swings or excessive dryness can affect its condition, so keep the enclosure out of direct sunlight and monitor conditions with a thermometer and hygrometer.

2. 2Choose the Right Substrate

   This beetle spends much of its time burrowed into the substrate, so use a generous layer of insect mat kept lightly moist. If the surface starts to dry out and harden, mist it lightly so the beetle can keep burrowing comfortably.

3. 3A Short Adult Lifespan

   In the wild, adults typically live only about 2 to 3 months, shorter than many other beetles kept as pets. Because their time as adults is limited, it helps to have temperature, humidity, and feeding set up properly from the moment they arrive.

4. 4Handle the Mandibles Carefully

   Males have thick, short, strongly curved mandibles with a firm pinching grip, so take care not to get a finger caught. When handling, support the thorax securely and keep your fingers away from the mandibles' range of motion.

5. 5Size Varies by Sex

   Males range from about 25 to 65.9mm and females from about 24.5 to 31.5mm, so individual size can vary quite a bit. Larger males also tend to develop more impressive mandibles, so choose an enclosure with enough room for full-grown size.

6. 6A Nocturnal Beetle

   During the day it often stays still, tucked away in the substrate or hidden spots, becoming active mainly at night. Low activity during daylight hours isn't necessarily a sign of poor health, so it's best to simply observe quietly.

7. 7Prepare Before It Arrives

   Have insect mat, insect jelly for food, and a thermometer/hygrometer ready before your beetle arrives so it can settle in right away. Choose an enclosure designed for beetles that balances ventilation and moisture retention, and check the room's temperature conditions in advance.

Frequently asked questions about Kumejima Saw Stag Beetle

Q.Is the Kumejima Saw Stag Beetle suitable for beginners?

A.Its care difficulty is generally rated for intermediate keepers, so first-time insect keepers may find temperature and humidity management a bit more demanding. Anyone with basic beetle-keeping experience should be able to care for it without much trouble.

Q.How long do adults live?

A.In the wild, adults typically live about 2 to 3 months. Since their adult life is relatively short, it's worth setting up a good environment from the start so they can spend that time comfortably.

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

A.Males range from roughly 25 to 65.9mm while females range from about 24.5 to 31.5mm, so males tend to be larger overall with a wider size range. Individual variation can be considerable even within the same subspecies.

Q.Does body color vary between individuals?

A.Body color ranges from dark reddish-brown to black, and individuals of the same subspecies can look quite different from one another. Even beetles raised in identical conditions won't necessarily end up the same shade.

Q.Is the Kumejima Saw Stag Beetle subject to CITES?

A.The Kumejima Saw Stag Beetle is not subject to CITES.

Useful tools for Kumejima Saw Stag Beetle care

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