Ebi Antony GEORGE "Who cares? Quantifying individual and...

Ants are currently the only known non-primate species to show social care of injured individuals. Social care behaviour in ants includes cleaning of the wound, applying antimicrobial compounds to it and even amputations of the injured body part. However, the identities of the caregivers and how the colony responds to injured ants remain unknown. We performed behavioural experiments in six ... Camponotus fellah sub-colonies using individuals with a sterile injury and a fungal pathogen infected injury. Combining 450 hours of video observations and 1400 hours of automated tracking data, we asked who provides care, what drives them to provide care and how colony social network topology adapts to the presence of injured individuals. We found that care is not provided reflexively nor by a group of specialised individuals. Instead, social affinity of nestmates with the injured ants in the time preceding the injury predicted whether an individual provided care. We also observed localised changes in colony networks with an increase in clustering of the network in response to the presence of injured ants. This was driven by ants which interacted with the injured ants, who showed a transient increase in the number of nestmates they were connected to following the introduction of the injured ants. The localised changes led to an increase in the resilience of the social network, presumably to buffer against the loss of injured individuals. Our results provide new insights into the role of social interactions in driving task performance and maintaining colony homeostasis in eusocial insects.

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