Sick cocooned ants release a smell to tell worker ants to destroy them to protect the colony from infection, Austrian scientists have revealed.

When adult worker ants get an illness that could spread through the colony, they leave the nest to die alone.

Young ants, known as pupae, in contrast are still trapped inside a cocoon, making this kind of social distancing impossible.

Scientists had already figured out that when these pupae are terminally ill, there is a chemical change that produces a particular smell.

Adult worker ants then gather around, remove the cocoon, “bite holes in the pupae and insert poison,” Erika Dawson, a behavioral ecologist at the Institute of Science and Technology Austria and lead author of a new study, told Agence France-Presse.

The poison acts as a disinfectant, which kills both the colony-threatening pathogen and the pupae.