What if ants could give us clues on how to avoid pandemics? Supported by an ERC grant of 1.5 million euros, biologist Nathalie Stroeymeyt is starting a key research project at the University of Fribourg this month. Its objective: to understand how ants modulate their social organization in order to avoid the spread of disease.

Emergency health measures

Like humans, indeed like any social species, ants have frequent contacts with each other that make them vulnerable to the spread of epidemics. It is therefore likely that over the course of evolution, ants have developed a social organization that can stop the spread of pathogens within the colony. "Ants are organized into separate working groups with relatively little interaction between groups”, explains Nathalie Stroeymeyt. “ This might help slow down epidemics, but it remains to be seen whether they are able to actively modify their social and spatial organization when they detect diseases in their environment.” To answer these questions, researchers needed the technical means to distinguish one ant from another and see who interacts with whom, and how often.

Tracking individual ants

Researchers from Professor Laurent Keller's group at the University of Lausanne, with whom Nathalie Stroeymeyt collaborated from 2010 to 2018, were the first to take up this challenge. "We were gluing a kind of QR Code on the thorax of garden ants (Lasius niger) in order to identify them, explains Nathalie Stroeymeyt. With the help of a camera, we then recorded their position twice a second." From the observation of very simple individual behaviours, entomologists can now understand collective behaviours. An unimaginable feat less than a decade ago!

Social vs. individual immunity

Although her research is limited to the insect world, Nathalie Stroeymeyt does not shrink from comparisons with human society: "With ants, we can study the spread of epidemic experimentally, which is not possible on humans for ethical reasons." In parallel to this "network analysis", Nathalie Stroeymeyt and her team, once settled in Fribourg, will seek to understand to what extent social organization affects the ants' immune system: "If, thanks to their organization in groups, ants succeed in avoiding the emergence of diseases in their nest, it may not be necessary for them to invest so much energy for individual immunity. We will test this hypothesis in the laboratory by measuring gene expression and with physiological tests.”

Text adapted from an article in the Universitas magazine (in French). Image credit: Timothée Brütsch.