Some insects (e.g., ants and some bees) live in intricately structured societies or colonies. Their colonies can comprise thousands of individuals specialized on different tasks. Most individuals are sterile, devoting their lives to colony tasks such as collecting food or feeding the young. More and more data suggest a link between the gut microbiota and animal social behavior. This link has previously been studied by observing interactions of pairs of individuals, but not at the societal level in a "hypersocial" animal. This knowledge-gap was filled by the discoveries made by Dr. Joanito Liberti, postdoctoral fellow in the departments of Fundamental Microbiology (DMF) and Ecology and Evolution (DEE) at UNIL, and Tomas Kay, doctoral student at the DEE, co-first authors of the article published in the journal Nature Ecology & Evolution