Sick baby ants sacrifice themselves to save their colony

[Buster's Uncle]

Popular Science
Sick baby ants sacrifice themselves to save their colony
Andrew Paul
Tue, December 2, 2025 at 11:00 AM EST
3 min read



The chemical alerts appear to be situational and depend on proximity to adult worker ants.


Ants are some of nature’s most selfless animals. They practice social distancing when ill, consistently act for the good of the colony, and will die to protect their queen from outsiders. This evolutionary drive is so strong that at least one ant species will even willingly sacrifice themselves before they leave their cocoons. The evidence, documented in a study published on December 2 in the journal Nature Communications, highlights a particular form of ant altruism.

While a single ant is a comparatively simple creature, things quickly grow more complex as you increase the total number of insects. An ant colony is one of the best examples of a superorganism—a population whose individuals function solely to serve the greater population. Some ant colonies reach upwards of 500,000 ants. In this sense, the colony operates as a form of collective intelligence similar to the various cells in the human body.

Researchers at the Institute of Science and Technology Austria (ISTA) recently witnessed a new example of ant superorganism behavior. After introducing Lasius neglectus ants to the fungal pathogen Metarhizium brunneum, the team monitored the insects as individuals and in group scenarios. Even before hatching from their cocoons, infected worker pupae exposed to the fungus began releasing a modified chemical body odor that informed nearby adult ants to kill them. What’s more, the subtle signalling only occurred when adult worker ants were close to the pupae.

When the young insects were not exposed to the pathogen, they didn’t emit the same chemical. This suggests the signal isn’t an unavoidable side effect of their immunoresponse system.

“By warning the colony of their deadly infection, terminally ill ants help the colony remain healthy and produce daughter colonies, which indirectly pass on the signaler’s genes to the next generation,” Erika Dawson, an animal behavioralist at ISTA and study co-author, said in a statement.

Additionally, this type of chemical warning must be incredibly precise in order to keep innocent bystander ants from dying. After analyzing the odor’s chemical composition, Dawson and colleagues found that the scent is tailored to the emergency at hand.

“The scent cannot simply diffuse through the nest chamber but must be directly associated with the diseased pupa,” explained Thomas Schmitt, a study co-author and a chemical ecologist at Germany’s University of Würzburg. “Accordingly, the signal does not consist of volatile compounds but instead is made up of non-volatile compounds on the pupal body surface.”

This signal didn’t apply to every type of ant, however. Queen pupae possess stronger immune defenses than their workers, which often allows them to limit the spread of their fungal infection. During lab observations, researchers didn’t document examples of any queens-to-be emitting the same warning signals.

“This precise coordination between the individual and colony level is what makes this altruistic disease signaling so effective,” added ISTA ecologist and study co-author Sylvia Cremer.

https://www.yahoo.com/news/articles/sick-baby-ants-sacrifice-themselves-160000658.html