Humans have cooperated with ants of the rufa group for centuries: reports from German and Dutch sources as early as the XVIII century describe artificial relocations of their colonies, with the aim to counteract the effects of parasitic arthropod infestations on conifers. Indeed, ants of the rufa group are generalist and voracious predators, and mature colonies are capable of consuming tons of insects every year.
In the first half of the XX century, scientists and researchers developed a special interest for these practices, and began to apply more rigorous methodologies and targeted studies on the use of ants for forest conservation. Those were years of intense experimentation (especially after the end of the Second World War), which led to the development of a new scientific and environmental consciousness and helped shaping the modern conception of forestry, environmental sciences and biological control.
Left: Mario Pavan (in black) and a researcher from the University of Pavia are doing lab experiments with Formica paralugubris. Right: Trucks transport barrels filled with Formica paralugubris. Frames from the documentary “La Formica Rufa Protegge i Boschi” (1957).
Our story begins at that time, in the early 1950s. Mario Pavan was an Italian scientist of international renown and a Professor of Entomology at the University of Pavia. His attention had been caught by a series of foreign experiments involving ants of the rufa group. He therefore decided to embark on a new research path: after mapping all the nests across the Lombard Prealps and Alps, and roughly determining which species were present, he began looking for an area suitable for the first experimental transplants.
He chose Monte Penice for this, in the Ligurian Apennines. The area had previously been planted with black pine (Pinus nigra), which was then heavily infested by large popolations of pine processionaries (Thaumetopoea pityocampa): the forest was endangered! Pavan thus collected nests of Formica paralugubris from the Alps, transported them in large barrels by truck, and released the ants into the new area. In just over a year, the pine processionary was wiped out… poof, gone!
Pavan continued the experiments, and after years of refinement, he decided to introduce Formica paralugubris to other forests across Italy as well. This time, however, his goal was not to exterminate parasites or annihilate voracious caterpillars, but rather to test the effectiveness of his precious ants as 'ecological stabilizers'. This way of thinking does not quite align with today's understanding of ecology, but at the time it was totally reasonable. Considering that these insects had a beneficial impact on the Alpine forests they inhabited, it was assumed that they could probably bring similar advantages to the Apennines and other Italian mountains. Therefore, the ants had to be introduced in those area too!
Pavan's experiments quickly gained international recognition: researchers from all over Europe, and even from North America, became fascinated in the ants of the Northern Italian Alps. Colonies of Formica paralugubris were even shipped from Italy to Germany, and as far away as Canada, travelling by plane in sealed boxes! These introductions continued until the late 1980s.
Today, such experiments would hardly be approved by the scientific community: releasing alien species into new areas can be very harmful to the environment, due to the risk of invasiveness. Formica paralugubris did not turn into such an environmental menance, as the introduced populations survived only in a few locations. However, these populations now exert a considerable impact on local arthropods, particularly displacing all other ant species and depriving them of almost all resources.
An clear nt example of this can be seen in some areas of the Casentinesi Forests National Park, where Formica paralugubris has become a ubiquitous and pervasive species.
Our scientific research began from those very areas.
To share the fascinating story of Formica paralugubris to the public, we are now planning to produce a documentary. If you are interested in finding out more or taking part in the project, do not hesitate to contact us!
Alberto Fanfani was a collaborator of Mario Pavan and the first person who was interviewed for our documentary.