Wood Ant Supercolonies: Thousands of Nests, One Family

Most ant colonies live in a single nest. Some red wood ants go much further: they build networks of hundreds or even thousands of connected nests that work together as one big family. These are called supercolonies, and they are among the largest animal societies on earth.

How does a supercolony form?

It starts with queens. In species such as Formica polyctena and Formica paralugubris, young queens are often taken back into their own nest after mating, so a nest can have many queens. When a nest becomes too crowded, part of the colony moves out with some of the queens and builds a new nest nearby. This is called budding. The new nest stays connected to the old one by trails, and workers, brood and food keep moving between them. Over the years, a whole network of nests grows this way.

One family, no fighting

Normally, ants from different nests fight each other. In a supercolony, workers from different nests treat each other as nestmates. They share trails, food and even brood, and the network behaves like one giant colony.

The record: Hokkaido

The largest wood ant supercolony ever described was found along the Ishikari coast of Hokkaido in Japan. It belonged to Formica yessensis, a member of the Formica rufa group, and consisted of more than 45,000 connected nests with more than 300 million workers and more than a million queens, spread over an area of about 2.7 square kilometres.

Supercolonies in Europe

Workers on a mound. In a supercolony, workers move freely between nests.

Europe has its own giants too. In the Alps and the Jura, Formica paralugubris forms supercolonies of more than a thousand nests. In lowland forests, Formica polyctena builds large groups of nests; a single large nest of this species can hold more than a million workers and thousands of queens. Across the Atlantic, Formica obscuripes, another relative, formed a supercolony of more than 200 nests and an estimated 56 million ants in Oregon.

Why is it such a success?

A supercolony can share workers and food between nests, quickly take over good feeding spots and replace queens when they die. That makes it almost immortal: as long as new queens are added, the colony can last for decades. Near large wood ant supercolonies, you often find fewer other ant species, because the wood ants claim most of the space and food.

Can you keep a supercolony?

No. A supercolony only works on the scale of a forest. In captivity, keepers start with a small colony with a single queen. Read what that involves in our Formica rufa care guide, or learn more about the species in the Formica rufa group. Or have a look at our Formica rufa colonies.

Sources

• Wikipedia. Ant supercolony.

• WSL / Waldwissen. Red wood ants in Switzerland.

• Wikipedia. Formica rufa group.

• Higashi, S. and Yamauchi, K., 1979. Influence of a supercolonial ant Formica (Formica) yessensis Forel on the distribution of other ants in Ishikari coast. Japanese Journal of Ecology.

Photos: © Jonghyun Park (CC BY 4.0), via iNaturalist.