Myrmica rubra
(Linnaeus, 1758)
European fire ant
Temperature
18–24 °C
Humidity
55–75%
Colony size
1,000–5,000
Queen size
6–7.5 mm
Worker size
4–6 mm
Hibernation temp
5 °C
Diet
Care Guide
Myrmica rubra, commonly known as the European fire ant or red ant, is a lively and rewarding species that offers a fantastic introduction to semi-claustral ant keeping. Unlike fully claustral species, the queen must leave the nest to forage during the founding stage, making these ants wonderfully interactive from day one. Colonies grow to several thousand workers, and it is not uncommon for a single nest to contain multiple queens – a trait called polygyny that accelerates colony growth and resilience. The queens measure 6–7.5 mm, while workers range from 4–6 mm. There is no pronounced polymorphism; all workers are similar in size, but they make up for it with energy and a powerful sting that is surprisingly noticeable for such small ants.
One of the most distinctive features of Myrmica rubra is their aggressive and efficient foraging behavior. These ants are relentless hunters of small insects and scavengers of protein-rich foods. Their diet must include a steady supply of insect prey – fruit flies, crickets, or mealworms – alongside sugar water or honey. Without sufficient protein, the queen will not lay eggs and the colony will stagnate. Their high metabolism also demands regular feeding; they are not seed-storers like Messor species. This need for fresh food makes keeping them a more hands-on experience, but it also means you get to watch impressive hunting and food distribution behaviors up close.
Care difficulty
Keeping Myrmica rubra is well suited for beginners, especially those ready to learn semi-claustral feeding. The main challenge is ensuring the founding queen receives food without being disturbed too much. Once the first workers appear, care becomes straightforward: maintain a regular feeding schedule of insects and sugar water. Their tolerance of a wide temperature range (18–24°C) and moderate humidity (55–75%) makes them forgiving of minor fluctuations. However, they do require a winter diapause – hibernate at around 5°C for several months – which is essential for long-term health and future reproductive cycles.
Housing
A formicarium for Myrmica rubra should provide good ventilation and a moist nest chamber, as they prefer slightly humid conditions. A standard acrylic or plaster nest works well, paired with a foraging arena where you can offer food and water without disturbing the nest. Because these ants are fast and can sting, ensure the arena has a secure lid or fluon barrier. During the founding stage, a test tube setup with a small feeding dish in a separate container is ideal – the queen will venture out for food, so provide easy access. As the colony grows, expand the nest gradually. They are not particularly sensitive to light, but peace and quiet during the early weeks helps the queen settle.
First days after purchase
After receiving your Myrmica rubra colony – whether a single queen or a small group – place the test tube or mini formicarium in a quiet, dimly lit spot. Do not offer food immediately; let them acclimate for a few hours. Then, place a small drop of sugar water and a tiny insect (like a pinhead cricket) near the entrance. If the queen is alone, she will need to feed within the first day or two – if she ignores the food, gently guide her towards it. Watch for signs of stress: excessive escape attempts or refusal to eat. Once she takes food, you can relax. Provide a constant water source via a cotton-plugged tube, and maintain a stable temperature around 20°C. The first workers will appear in a few weeks, and from then on, the colony will grow with enthusiasm.