Sick Ants Take Medicine, Too

Humans aren’t the only animals who have learned to fight off infections with medicines. In a study that will be published in the journal Evolution, researchers from the University of Helsinki report that ants who come into contact with a harmful fungus then seek out foods that fight infection.
The researchers observed 400 ants, some of whom had been exposed to a disease-causing fungus. All the ants had access to an eggy food the scientists had laced with hydrogen peroxide, a reactive oxygen species (better known as free radicals). Those who had been exposed to the dangerous pathogen took the peroxide-laced food, while uninfected ants didn’t go for it at all.
Reactive oxygen species are harmful to healthy ants, but when the ant was already been exposed to the fungus, the cellular destruction associated with the fungus became a worthwhile trade off, since it also damaged the fungus cells. The fungus-exposed ants preferred the peroxide food before and after developing infections, and eating it increased their survival chances by 30 percent.
[h/t: Scientific American]