Constraints and benefits of leg amputations to combat wound infections in ants

• Applicant: Privatdozent Dr. Erik Frank
• Subject Area: Sensory and Behavioural Biology ; Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 567282475

Altruistic care for injured individuals, long recognized in human societies, has increasingly been documented in non-human animals, from primates to rodents. Social insects in particular demonstrate a diverse repertoire of injury and disease management behaviours collectively referred to as social immunity. Beyond well-studied disease management (e.g., allogrooming, corpse removal), recent findings show that ants also treat open wounds by licking or applying glandular secretions. Strikingly, some species even perform limb amputations on injured nestmates to halt pathogen spread. Although these behaviours have been repeatedly observed under laboratory conditions, the extent to which ants rely on amputations versus antimicrobial secretions and the evolutionary factors shaping such choices remains poorly understood. This project aims to fill these knowledge gaps by systematically investigating limb amputations and antimicrobial wound care across ant genera with contrasting ecology, morphology, and social organization. First, by examining injury responses in Camponotus cruentatus under natural conditions in Spain (Objective 1), we will determine the behavioural and pathogen-related factors that drive or limit amputation behaviours. Second, by studying Atta sexdens leaf-cutter ants in Argentina (Objective 2), we will test the role of metapleural gland secretions relative to amputations, thereby clarifying the adaptive trade-offs between these wound care strategies. Third, a comparative survey of ten additional German ant species will explore the morphological traits that either enable or constrain amputations (Objective 3). Ultimately, our interdisciplinary approach across behavioural ecology, chemical ecology, and microbiology will not only pinpoint the benefits, costs, and physiological limits of amputation as a wound care strategy but also illuminate how distinct evolutionary pressures have convergently shaped these remarkable medical interventions in ants. Insights from this research will deepen our understanding of social immunity’s plasticity and shed light on broader evolutionary pathways underlying altruistic care in animal societies.

• DFG Programme: Research Grants