Identikit

To fully understand the biology of Formica paralugubris, we need to introduce the reader also to the larger group it belongs to, the Formica rufa species group.

Known by the common name of "red wood ants", the at-least seven European species of the rufa group (Formica rufa, Formica aquilonia, Formica polyctena, Formica pratensis, Formica truncorum, Formica lugubris, and oure beloved Formica paraluguris) share morphological, ecological, and behavioural characteristics, making their identification and differentiation difficult to non-experts (and to experts, too!). Red wood ants are mostly bichromatic, with a reddish head, a reddish mesosoma with brown central spots, and a darker gaster. To make things harder, hybridization is also a common phenomenon in this group, and is further amplified by habitat overlaps between different species. Although in the past hybridization was considered detrimental to the genetic diversity of a population, today we know that things are much more complex and multifaceted, as it may even enrich species and genetic diversity (as the ants of the rufa group perfectly exemplifies).

Red wood ants form numerous colonies inhabiting the northern regions of the world (i.e., they have a Holartic distribution), where, by using needles fallen from the canopy and resin secreted by the tree trunks, they build their impressive nests inside the dense conifer forests. These entomological engineering masterpieces are generally dome-shaped, and can reach up to 2 meters in height. At their base, they hide countless tunnels and safe chambers, that are provided with stable temperatures and excellent ventilation. Often, multiple nests are connected to each other through multi-branched underground corridors, so that the area occupied by a single colony can reach over tens or hundreds of square meters! Such large spaces are inhabited by a massive quantity of ants: mature colonies often count tens of millions of individuals, including queens, workers, pupae, larvae, and brood. Some species can present a remarkable polygyny, that is, the presence of several queens (usually related) within the same colony. The co-existence of multiple royals within the same nest means that the population can grow at dizzying rates, with peaks reaching 400 million individuals per colony in extreme cases.

The presence of the red wood ants provides many ecological services to an ecosystem, which can be appreciated both on and under the ground level: with a powerful impact on the predator-prey dynamics, in the recycling of nutrients, in the dispersion of seeds and in the regeneration and modification of their habitat, these ants are to be considered as keystone species. In other words, they play fundamental and structural roles in their ecological communities. Therefore, it is not surprising that in many countries these insects are protected by strict laws, although their populations often remain threatened by various factors, such as the increase of artificial forestry, and the corresponding ecosystem impoverishment and habitat loss.

If you have encountered unfamiliar terms while reading, we invite you to take a look at the Glossary section, which includes technical jargon related to ant anatomy, ethology and genomics!