To groom or not to groom: 'Triage' in the ant kingdom
Published:11 Jul.2023 Source:Institute of Science and Technology Austria
Ants are a perfect model to study cooperation, especially when it comes to preventing the spread of disease. Similar to a hospital, healthy individuals take care of sick ones. However, while a hospital has established rules of triage to determine whom to treat first, the individual decisions that ultimately form the collective hygiene of an ant colony have been unclear. Until now.
To unravel an individual ant's decision-making when treating colony members, experimental biologist Sylvia Cremer and her research team at ISTA have teamed up with colleague and theoretical physicist Gašper Tkačik and mathematician Katarína Boďová from the Comenius University in Bratislava. In their multidisciplinary study published in the journal Nature Communications, the scientists used garden ants and fungal germs to understand what information ants take into account when performing their individual grooming choices.
Observation of the ants' behavior and analysis of the spore load -- the amount of fungal spores -- of each colony member over time revealed that ants preferentially target the most infectious nestmate for grooming. Additionally, ants do not groom other ants just after they were groomed themselves. Ants therefore not only assess the contagiousness level of others but are also sensitive to the social feedback they receive on their own infectiousness from the colony. This unique combination of simple rules leads to the fact that the most infectious colony members are groomed by the least infectious colony members, resulting in highly efficient colony-level disease control.