Ants Self-Medicate by Ingesting Typically Toxic Foods

Although hydrogren peroxide is typically toxic for ants to ingest, it might just be the saving grace for those infected with a life-threatening fungal disease. 

Ants, like many other insects that live in social colonies, are particularly at risk to parasite infections and fungal disease due to their low genetic diversity, high density, and the hot and humid conditions found in their nests. 

“It is natural that [ants] have evolved amazing mechanisms to counteract microorganisms, and self-medication is one of those,” said David Baracchi of Queen Mary University of London. He believes that self-medication is likely widespread throughout the animal kingdom, New Scientist reports. “We just have to keep looking for this behavior.” Earlier this year, Baracchi and his colleagues showed that bumblebee may use the nicotine present in the nectar of some flowers to do something similar.

What is especially interesting is not only the fact that the ants studied know to ingest hydrogen peroxide, but that they will only consume the proper dosage. Nick Bos and his colleagues at the University of Helsinki, Finland fed diets one of two studies – either a simple honey-based solution, or the same solution spiked with hydrogen peroxide. Ants that consumed the spiked diet had a mortality rate of around 20 percent, while those given the honey-only solution had a mortality rate of 5 percent. 

When the ants were offered the option between the spiked and harmless solutions, healthy ants tended to avoid the spiked foods, while the infected ants ate the hydrogen peroxide solution. Not only that, when the toxic solution was weak, the infected ants consumed larger quanities and when the solution was stronger, limited their intake.