Formica rufa

Exploring many paths of the Alpi Cozie Protected Areas, through coniferous forest formations, it is possible to observe large piles of needles and plant debris that constitute ant nests, particularly interesting in the field of biological control.

On the Italian Alpine arch, there are four species of hymenoptera, very similar from an ecological and morphological point of view, which are referred to as ants of the Formica rufa group. These ants have a rust-red coloration on their livery, with a brown abdomen, legs, and antennae. They are stingless but equipped with two robust mandibles.

Their complex social life involves a larger part of the population represented by workers who perform various tasks: procuring food, maintaining the nest, defending it from aggressors, caring for eggs and larvae, and feeding the queens.

The queens are fertile females initially provided with wings that, once their development is complete, leave the nest and are inseminated by males during the "nuptial flight." The males, after mating, have a very short life, while the queens land to found a new nest or more often return to live in the original nest. After shedding their wings, they immediately start laying eggs, from which mainly workers will hatch.

The differentiation into the three castes (workers, males, queens) is controlled by various factors, including the temperature at which the eggs are laid, the type of larval nutrition, the number of workers in the nest, the presence or absence of queens.

The nests of Formica rufa can reach dimensions of one meter in diameter at the base and one meter in height, with a population of 500,000 - 1,000,000 individuals. The emergent part is called "acervo" and is used when the climatic conditions are more favorable, while the deeper parts of the structure are inhabited during the winter.

The importance of these ants in maintaining ecosystem balances is linked to the extraordinary quantity of insects and arthropods that are captured for the food needs of the colony (tens of thousands per day). Positive transplants of ant colonies have been carried out both in Italy and abroad in areas infested by harmful insects, demonstrating their effectiveness in the field of biological control.

Conservation Status

The Formica rufa is included in the IUCN Red List as a near-threatened species. In Piedmont, it is protected under Regional Law 32/1982.