Ants self-medicate when sick, say Finnish researchers. Researchers from University of Helsinki, Finland, did a series of experiments on the black ant Formica fusca and found that when the ants get infected by a local fungus, they seek out and eat a certain type of food.
The sick ants eat hydrogen peroxide to fight the fungus. Hydrogen peroxide is an antiseptic and is also used for bleaching. It releases free oxygen that kills off fungus. Ants find it in damaged plants, other insects and cadavers. The scientists found that taking the medicine increased the chances of infected ants surviving by 20 per cent. The fungal disease is lethal to these ants.
Hydrogen peroxide containing food was avoided by healthy ants and eaten only by infected ones, the researchers found. If healthy ants are given hydrogen peroxide it damages their health. So it was definitely a choice being made by the ants. Also, when the scientists increased the quantity of hydrogen peroxide available for consumption, the ants consumed less of it. This implied that the ants were consuming a certain dosage of the ‘medicine’.