Speaker
Description
Social insects live in densely populated colonies, which increases the risk of disease outbreaks. As a result, they have developed collective strategies for disease defense known as ‘social immunity.’ For instance, social insects groom infectious fungal spores from each other’s body surfaces to prevent infection. Social immunity depends on the ability to identify infected conspecifics, but the chemical and sensory bases of this detection remain poorly understood.
We aim to explore the mechanistic bases of social immunity using the queenless clonal raider ant Ooceraea biroi, a blind species that likely detects sick nestmates by olfactory cues. However, other modalities (e.g., gustation) might also play a role in detecting sickness-related cues. Our objectives are to 1) identify candidate olfactory “disease-related cues” by comprehensively screening the chemical profiles of infected ants, 2) characterize the behavioral responses of workers towards nestmates infected with different pathogens and using this response to functionally test candidate chemicals, and 3) investigate how “disease-related cues” are encoded in the brain through in vivo calcium imaging of the antennal lobe. Additionally, we will examine neuronal responses to pathogen odors and compounds that are known to trigger social immunity behavior (e.g., ergosterol). Preliminary behavioral data indicate a response of non-infected nestmates towards bacteria-infected individuals at specific time points following bacterial infection. The chemical analysis of bacteria-infected ants revealed several candidate compounds that could be involved in eliciting the observed behavior towards infected individuals.
By combining chemical, neuronal, and behavioral analysis, we anticipate shedding light on the mechanistic bases of social immunity in insect societies.
