How to Identify a Formica Rufa?

Their waist, known as the petiole, has only one section. However, the key distinguishing feature lies in the tiny hairs on their bodies. They are the most efficient way to distinguish rufa from polyctena as polyctena is almost hairless.

The frequent hybridization of the two species makes the identification work even more complicated. Formica rufa is commonly found in the forest of Europe, from Spain to Russia.

Life under the Formica rufa’s dome

Rufa’s nests vary in size, ranging from small mounds to large hills.

Formica rufa constructs its nests using spruce and pine twigs, sometimes incorporating grass and hay. Their nests are typically built upon tree stumps, with tunnels and chambers dug among the roots. The tree stump and its roots form the anthill’s skeleton, while the layer of twigs serves as its skin, and the tunnels act as its organs.

A mature nest can house over 100,000 ants, living in a complex system of tunnels and chambers. The dome is the most important part, but also the most exposed to potential threats.

What materials are used to build Formica Rufa’s nest?

The dome helps regulate the temperature in both summer and winter. Eggs, larvae, and pupae are moved from one chamber to another based on the required temperature. Therefore, the larvae can be underground, or close to the dome surface.

During the summer, the temperature inside the nest stays between 25-30°C. Ventilation corridors assist in dissipating excess heat. Some of these corridors serve as pathways, while others function as actual ventilation ducts. In winter, the ants hibernate, and the queen stops laying eggs. The survival of the company depends on the dome resistance to the rain, snow and frost.

Myrmecophiles species: co-inhabitants of the Nest

Additionally, over 70 species, including many beetles and even bees, live peacefully near the nest. For instance, the rove beetle, which preys on small insects, often finds refuge in the vicinity of the nest.

Similarly, the golden-haired beetle, known for its striking appearance, can frequently be seen foraging nearby. Bees, such as the solitary mason bee, also make their homes close to the nest, benefiting from the protection and resources available in the area. These diverse species coexist harmoniously, creating a vibrant and dynamic ecosystem around the nest.

The Formicoxenus nitidulus ant species is quite unique! They live within the nests of 11 other ant species, including Formica rufa. Although they share a similar coloration with Formica rufa, as both are wood ants, they are smaller and have entirely red heads. They discreetly establish their nests among the Rufa anthills. Surprisingly, the Formica rufa ants allow them to coexist peacefully!

Federation and Wars

Formica rufa, commonly known as the red wood ant, is renowned for its complex social structures and behaviors. One of the most fascinating aspects of their society is their ability to form large federations, which are essentially alliances of multiple colonies. These federations can cover extensive areas and consist of numerous nests that cooperate for mutual benefit, such as sharing resources and defending territory.

However, this cooperative behavior does not extend to all ant colonies. Formica rufa is also known for engaging in fierce wars with other ant colonies, including those of their own species. These conflicts often arise when colonies compete for the same ecological niche, such as food sources, nesting sites, or territory. The battles can be intense and involve large numbers of ants, with each side deploying various strategies to outmaneuver and overpower the other.

Each colony has a unique chemical signature, and ants use this to recognize their nestmates and identify intruders. When ants from different colonies encounter each other, the recognition of these chemical differences often triggers aggressive behavior, leading to conflicts.

These wars are not just random skirmishes but are part of a broader strategy to dominate and control valuable resources. The spoils of war are not so visible as thousands of ants died. The resolution of the conflict leads the victorious colony to access to more territory, ressources and growth.

They also scavenge dead insects or hunt live ones, collecting from 100 grams to 30 kg of insect meat annually, depending on the colony size.

Formica rufa also engages in mutualism with aphids, feeding on their honeydew and protecting them from predators like ladybugs. However, this relationship has its limits, as ants sometimes bring aphids into the nest to feed the larvae. A big nest potentially collects up to 500 kg of honeydew per year!

Threats to the Dome

Threats towards  individuals

As an individual, a Formica rufa encounters numerous threats in its natural habitat. Among these, mites pose a significant challenge, often infesting their nests and causing health issues for the ants. Additionally, predators such as spiders and mantises frequently target these ants, taking advantage of their smaller size and vulnerability. These threats necessitate constant vigilance and adaptive strategies.

Collective Threats

Other ant species also compete with Formica rufa for resources, further complicating their survival. 

Boars and birds are natural predators. They destroy part of the anthill in order to eat larvae which are rich in protein. If a rain fall follows their visit, the anthill can suffer major floods that could end the colony.

Sometimes, birds provoke F. rufa. They except the ants to attack them with their formic acid. This way, they expose their furthers to a natural anti-parasitic bath.

Today, human activities are the main threat to F. rufa. That could be because of the expansion of the agriculture fields, the use of pesticides or the removal of woods and forests.

Rufa population decreases. A few European countries already placed them on the red list of endangered species:

Formica rufa is one of the most iconic ant species, with their impressive dome-like anthills prominently visible in forests. Despite their importance in ecosystems, their role is often overlooked. They aerate the soil, spread seeds and pollen, serve as prey for birds and other insects, and help control pests. Next time you see one of their domes, take a moment to appreciate their ecological significance and share this knowledge with others!