Red Wood Ant Facts: 12 Things About Formica rufa
Updated: 1 day ago
The red wood ant is one of the best-known ants in Europe. Its big mounds of pine needles are a familiar sight in many forests, and there is a lot more going on inside them than you might think. The name usually refers to Formica rufa, but it is also used for a whole group of closely related species, the Formica rufa group. Here are 12 facts about red wood ants.
1. Their mounds can be 2 metres high
A large mound can be up to 2 metres high and 5 metres across. And that is only the part you can see: underground, the nest can reach up to 2 metres deep. Read how it works in how a red wood ant mound works.
2. One nest can hold up to two million ants
A single mound can house anywhere from a few hundred thousand to around two million ants, depending on the species and the age of the nest.
3. A nest can have many queens
Many red wood ants are polygynous: young queens are often taken back into their own nest after mating. In some species, such as Formica polyctena, a large nest can hold thousands of queens.
4. Queens can live for more than 20 years
A red wood ant queen can live for more than twenty years and lay up to a million eggs in her lifetime.
5. A queen cannot start a colony on her own
A young red wood ant queen cannot raise her first workers alone. She sneaks into the nest of another Formica species, such as Formica fusca. The host queen is killed, and the host workers raise the red wood ant brood as if it were their own. Over time, the host workers die off and the nest becomes a red wood ant nest.
6. They heat their own nest
From spring to autumn, red wood ants keep the inside of their nest at a warm and stable temperature, often 25 to 30 degrees. In early spring, workers even sunbathe on top of the mound and carry the heat inside.
7. They gave formic acid its name
In 1671, the English naturalist John Ray distilled large numbers of red wood ants and obtained an acid. It was named formic acid, after formica, the Latin word for ant. Read more in formic acid: how red wood ants spray.
8. They make their own medicine
Red wood ants collect pieces of conifer resin and bring them into the nest, up to 20 kg in a large mound. Resin protects the colony against bacteria and fungi, and the ants make it even stronger by spraying formic acid on it.
9. They mostly live on honeydew
About two thirds of their food is honeydew, the sweet liquid produced by aphids. Workers climb all the way to the tops of the trees to collect it, along trails that can be up to 100 metres long.
10. A big nest catches millions of insects
A large nest with a million ants needs around 30 kg of insects a year, roughly ten million prey animals. That is why red wood ants are so important for the forest. Read more in why red wood ants are good for the forest.
11. They plant flowers
Cow-wheat and many other forest plants have seeds with a small, tasty appendix. Wood ants carry these seeds back to their nest, eat the appendix and leave the seed, which can then grow into a new plant.
12. They are protected in several countries
In Germany and Switzerland, wild wood ant mounds are protected, so you may not disturb them or take ants from them. Switzerland has protected them since 1966, and the IUCN lists Formica rufa as Lower Risk/Near Threatened, based on an old assessment from 1996.
Bonus: they are used to make yoghurt
In parts of Bulgaria and Turkey, red wood ants are traditionally used to make yoghurt. The ants help the milk to curdle.
More about red wood ants
Want to know more? Read about the species in the Formica rufa group, wood ant supercolonies or our Formica rufa care guide. Or have a look at our Formica rufa colonies.
Sources
Wikipedia. Formica rufa.
WSL / Waldwissen. Red wood ants in Switzerland.
Planet Wissen. Rote Waldameise.
Chapuisat, M. et al., 2007. Wood ants use resin to protect themselves against pathogens. Proceedings of the Royal Society B.
Photos: © Jonghyun Park (CC BY 4.0) and © Daniel Onneweer, via iNaturalist.
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