Lasius neoniger
Temperature
20–26 °C
Humidity
50–70%
Colony size
3,000–15,000
Queen size
7–9 mm
Worker size
3–4.5 mm
Hibernation temp
6 °C
Diet
Care Guide
Lasius neoniger, often known as the “cornfield ant” or “Labrador ant,” is a classic North American species prized by keepers for its rapid colony growth, cooperative foraging behavior, and striking diurnal activity. The queen, a sleek dark-brown to black insect measuring 7–9 mm, raises her first brood entirely on her own metabolic reserves, never needing to leave the founding cell to feed. Her workers are smaller, ranging from 3 to 4.5 mm, and the colony can eventually reach a remarkable 3,000 to 15,000 individuals. This species is strongly monomorphic, meaning all workers look similar in size and shape, but their coordinated efforts are a joy to watch as they form well-defined foraging trails during daylight hours.
A key feature of Lasius neoniger is its need for a true period of winter dormancy. In the wild, these ants retreat deep into their mounds and slow their metabolisms for several months. To keep them healthy in captivity, you must provide a hibernation phase at around 6°C for at least three months. Only after this cold rest will the queen resume egg-laying and the colony thrive through the next active season. Their diet is simple and forgiving: they eagerly accept sugar water or honeydew for energy, and require a steady supply of insects such as fruit flies, mealworms, or crickets for protein. Because they are claustral founders and do not require live prey during the first few weeks, new keepers find this species exceptionally easy to start.
Care difficulty
Keeping Lasius neoniger is one of the most beginner-friendly experiences in the ant-keeping hobby. Their resilient nature, fast development, and tolerance of minor fluctuations in temperature and humidity make them an ideal first colony. The main challenge — and the most important lesson — is remembering to provide a proper hibernation period each winter.
Housing
A formicarium for Lasius neoniger should maintain a temperature range of 20–26°C and a relative humidity of 50–70%. The nest needs to be kept slightly moist in one area to allow the larvae to develop properly, but good ventilation is equally important to prevent mold. These ants are not particularly sensitive to light or vibrations once established, but they do appreciate a quiet, stable location without strong air currents. As the colony grows, ensure they have an outworld large enough for foraging and waste disposal — they produce noticeable amounts of ant dirt and discarded food.
First days after purchase
When your Lasius neoniger colony arrives, set the formicarium in a dim, quiet spot and give the ants a full day to settle. Offer a drop of sugar water on a cotton ball and a small piece of insect protein. Do not handle the queen or disturb the founding chamber. Observe from a distance: they will quickly begin exploring and cleaning the new nest. In the first week, resist the urge to clean the outworld — the ants will manage it themselves. Once you see workers accepting food and the queen laying eggs, you can start to enjoy their dynamic, sun-loving personality.