Camponotus japonicus
Temperature
22–28 °C
Humidity
50–70%
Colony size
3,000–15,000
Queen size
15–18 mm
Worker size
7–13 mm
Hibernation temp
8 °C
Diet
Care Guide
Camponotus japonicus is a classic Japanese carpenter ant species, beloved for its impressive size and relatively easy care. The queen is a striking figure, measuring between 15 and 18 mm, and she is the largest member of the colony. Workers range from 7 to 13 mm, showing moderate size variation — not the extreme polymorphism of some Camponotus, but enough that you'll notice larger majors developing as the colony matures. These ants are claustral founders, meaning the queen seals herself into a chamber after mating and raises her first brood entirely on her own metabolic reserves. Once the first workers emerge, the colony grows steadily, eventually reaching a comfortable size of several thousand to well over ten thousand workers.
One of the most rewarding aspects of Camponotus japonicus is its diverse diet. These ants thrive on a mix of carbohydrates and protein. They eagerly accept sugar water, honey water, or honeydew from aphids, and they need a steady supply of insect protein — small crickets, mealworms, or even bits of boiled egg — to fuel brood production. They are not picky eaters, which makes feeding simple for beginners. Like many temperate Camponotus, they require a genuine hibernation period. Starting around late autumn, the colony should be gradually cooled to about 8°C for three to four months. Skipping hibernation can lead to queen exhaustion and colony decline, so plan for it from the start.
Care difficulty
Keeping Camponotus japonicus is ideal for beginners. Their claustral founding means no complicated feeding during the early stages; you simply wait in darkness for the first workers. Their tolerance for typical room temperatures and their robust diet reduce the risk of common beginner mistakes. The only real challenge is remembering to provide a proper hibernation period, but that’s easy to manage with a small refrigerator or cool basement.
Housing
These ants appreciate a dry nest with a separate humidified outworld. Use a formicarium with chambers that can be kept at around 50–70% humidity — a good test is to see a slight condensation on the walls but no pooling water. Camponotus japonicus are active foragers, so provide a spacious outworld with a heat mat set to 22–28°C on one side to create a thermal gradient. They are not overly sensitive to light or vibrations once established, but during the first weeks after the queen lays eggs, keep disturbance to a minimum. A test tube setup works perfectly for founding; later, connect it to a larger nest.
First days after purchase
When your new colony arrives, place the transport tube or test tube into a quiet, dark space. Give them at least 24 hours to settle. Don’t open the tube or shine bright lights on them. Check that the cotton plug or water reservoir is still damp — they will drink from it. Offer a tiny drop of sugar water on a cotton ball placed near the entrance. If the colony already has a few workers, they will find it quickly. Avoid offering any protein until you see the queen actively feeding or the workers carrying food into the nest. Over the next week, observe from a distance; patience is rewarded with a confident, fast-growing colony.