Some ant queens sometimes devour their babies, here's why

Some creatures are willing to do anything to survive. Ants, in particular, do not hesitate to adopt radical behaviors to ensure the survival of their colony. But why do queens eat their own offspring?


While we shared with you a few months ago the sophisticated method they use to treat their peers in this article, and more recently their ability to choose between healing or amputating their comrades' limbs depending on their injuries in this other article, a new study conducted by the University of Oxford reveals today the queen ant's ability to become cannibalistic, and explains why. It appears to be a defense strategy to combat disease within the nascent colony.

Researchers observed that the queens of the black garden ant (Lasius niger) consume their larvae infected by a pathogenic fungus. This behavior is seen as an effective means to prevent the spread of deadly infections in the colony.

During the experiment, researchers exposed black garden ant queens to two groups of larvae: one infected by a pathogenic fungus, and the other made up of healthy larvae. The infected larvae had been exposed to the fungus for 24 hours, a stage where the infection was lethal but not yet contagious.

The results showed that the queens consumed 92% of the infected larvae, chewing on them for several hours until no trace remained. By contrast, only 6% of healthy larvae suffered the same fate, proving that the queens could accurately detect the sick larvae. This early action eliminates the potential source of contamination before the infection could spread to the rest of the colony.

Moreover, the queens don't just take measures to protect their colony. They also seem to derive a nutritional benefit by recycling the sick larvae to produce more eggs. In fact, the study's results show that queens who consumed their infected larvae laid 55% more eggs. A crucial resource, as these eggs are essential for the colony's survival.

Researchers hypothesize that queens secrete an acidic and antimicrobial venom from a gland located at the end of their abdomen. This venom would be released and ingested during the cannibalism process, thereby neutralizing pathogens in the infected larvae.

This chemical protection would allow the queens to digest the larvae without risking infection themselves. Laboratory observations even showed some queens massaging this gland while consuming their larvae, reinforcing the idea that this venom plays a key role in preventing the spread of disease.

Curiously, this cannibalism is reserved for queens, as worker ants have other means of removing infected cadavers from the colony. This behavior raises questions about the evolution of survival strategies in social insects. Researchers hope that future studies will reveal additional benefits for the colony.