Social insect colonies are protected against disease by cooperative disease defences of their colony members, providing social immunity to the colony. We use ants as a model system to understand the emergence, mechanisms and fitness effects of social immunity.
The colonies of ants and other social insects are built up by distinct castes. The reproductive caste – the queens and the males – produce new offspring, whilst the sterile worker caste performs all other tasks of colony maintenance. This clear separation into a reproductive germline and a sterile soma has shaped the evolution of a social immune system that acts in addition to the individual immunity of colony members to protect particularly the reproductive colony members from disease. Social immunity measures range from collective nest hygiene, sophisticated sanitary care of pathogen-contaminated individuals to prevent their infection to effective treatment of infections and modulation of the interaction network to limit transmission.
We study the behavioural, chemical and immunological mechanisms of individual and social immunity in ants, and how they affect epidemiology in the colony and ultimately colony fitness.
Animal social networks are shaped by multiple selection pressures, including the need to ensure efficient communication and functioning while simultaneously limiting disease transmission. Social animals could potentially further reduce epidemic risk by altering their social networks in the presence of pathogens, yet there is currently no evidence for such pathogen-triggered responses.