A new study has found that young ants release a chemical signal asking to be killed when they become fatally ill, helping protect their colony from dangerous infections. The research, led by scientists in Austria, shows how ant societies act like a "super-organism," prioritising the survival of the colony over the individual.
Experts say ant nests are highly vulnerable to disease because thousands of ants constantly interact in close spaces. While adult worker ants can leave the nest to die alone when they fall ill, young ants - called pupae are sealed inside cocoons and cannot isolate themselves.
Scientists had previously observed that terminally ill pupae emit a strong smell caused by chemical changes in their bodies. Worker ants recognise this scent, tear open the cocoon, and inject poison into the pupae. The poison disinfects the nest by killing both the infected pupae and the pathogen.
In the latest experiments, researchers extracted this smell and applied it to healthy pupae. Worker ants destroyed them as well, confirming that the scent acts as a clear "destroy me" signal. Further tests showed that sick pupae only release this smell when workers are nearby, indicating that the signal is deliberate.
Researchers describe the behaviour as an altruistic act that helps protect the colony and ensures that shared genes survive.
However, queen pupae behave differently. The study found that when queens fall ill, they do not release this warning signal. Scientists discovered that queen pupae have stronger immune systems, allowing them to fight off infection without needing to signal for destruction.
The researchers now hope to investigate whether queen pupae ever signal for sacrifice when they cannot overcome an infection. The findings were published in Nature Communications.
