Anticipatory immunity in social insects?

Social groups are often at heightened risk of infectious disease transmission, yet they possess intricate mechanisms to counteract such threats. Beyond individual immune responses, social organisms employ collective cooperative disease defenses, exemplified by the remarkable strategies observed in social insects like ants, termites, and social bees. These species exhibit sophisticated behaviors, including sanitary care such as grooming and application of antimicrobials, effectively safeguarding their colonies from disease. Recent studies have suggested the existence of "anticipatory immunity" in vertebrates, wherein individuals upregulate immune responses upon perceiving disease cues in conspecifics. However, the extent to which social insects detect disease threats remains unclear, particularly regarding their ability to sense volatile cues over distances. In this study, we aim to investigate whether ants can anticipate impending infections by upregulating both individual and collective disease defenses in response to possible airborne cues of disease. We have developed an experimental setup, where pathogen-treated ant brood is presented to- yet remains physically separated from- healthy nest chambers, allowing only airborne compounds to pass. We employ gas chromatography-mass spectrometry coupled with thermodesorption to identify volatiles emerging from pathogen-treated brood, and analyze the healthy colony members exposed to these volatiles, for their immunity and  sanitary care behaviors. This approach allows us to test whether whole-colony disease prevention in social insects is made highly efficient by anticipatory individual and/or social immunity.