Ants have developed a long series of methods to prevent or fight contagious diseases, a gigantic problem for an animal that lives in colonies with thousands of specimens in very close contact. We know, for example, that they isolate their sick companions by placing them in quarantine, and if necessary they isolate themselves knowing they are infected.
Now a study published in preprint version on bioRxiv demonstrates that the health protocols of ants also apply to their architectural choices: an infected colony builds its anthill differently from a healthy one.
Healthy architects, sick architects. The experiment featured ants of the species Lasius nigerthe “classic” black ants found in every garden. We know that this species (and other ant species, actually) have the ability to adapt the architecture of their nest to external needs: for example based on the temperature, or the composition of the soil. The team from the University of Bristol then tried to study how an anthill changes if it is built by an infected colony.
the study. The first step of the experiment was to take two groups of 180 worker ants, introduced them into a container full of soil and left free to start building the anthill for 24 hours. After that, another 20 workers were added to the two groups: in one of the two cases, the new arrivals had been exposed to fungal spores, and bore signs of the infection. At that point, the ants were left free to build the anthill for another six days.
Antivirus protocol. Meanwhile, the team monitored the construction of the anthill and documented it with three-dimensional scans of the structure. In this way, the researchers discovered that the nest built by the infected ants had a different shape than that made by the healthy ones: the entrances were more separated from each other, and the internal connections between the different chambers of the anthill were much less frequent. In other words, the entire structure was built to minimize contact between specimens, so as to slow the spread of the infection.
Self-isolation. The ants also applied all other known health protocols, in particular self-isolation: this practice in particular proved extremely effective in preventing the infection from spreading rapidly. It is the first time that we have observed a non-human animal modifying the architecture of its nest for health reasons: the hope is (also) that we can copy some of their solutions to rethink human social spaces too.
