Ants of the Formica Fusca species have discovered a way to fight off harmful fungal infections. They have discovered that hydrogen peroxide, though normally very dangerous to them, can sometimes be salubrious or, good for their health.
Dense colonies of social insects such as ants can be especially vulnerable to parasitic infections and fungal diseases because they have low genetic diversity due to their high density and the high humidity and temperatures of their habitats. When ants get sick, they sometimes ingest foods rich in hydrogen peroxide in order to drive out the infection. In their natural habitats these foods could be things such as aphids or other decaying ants. They seem to have realized that their chances with the hydrogen peroxide are much better than their chances with the infections.
Hydrogen peroxide is a potent source of reactive oxygen species (ROS). These are chemicals that can be harmful to the body, but also help defend against invasions from unwanted pathogens. The risk of consuming ROS seems worth it considering that they weaken the fatal parasites.
In Finland, Nick Bos and his colleagues at the University of Helsinki have found that, while carrying dangerous fungal infections, the ants deliberately choose to ingest hydrogen – and as a result are more likely to survive.
The team fed healthy ants two different foods, a honey-based food with no harmful chemicals, and the same food with added hydrogen peroxide. Around 20 percent of the ants given the spiked food died, compared to about five percent of those given the normal food.
They attempted the same experiment a second time using ants infected with the fungus Beauveria Bassiana. The death rates of the infected ants given the honey-based solution were about 60 percent, while only 45 percent of those given the food containing hydrogen peroxide died.
During their trials they noticed that the healthy ants tended to avoid the laced solution while the infected ants ate more of it. It was also noted that the ants chose their dosage very carefully – the stronger the solution the less they fed on it.
It is still unknown how the ants know they are infected but it is apparent that their behavior changes once they are. David Baracchi of Queen Mary University of London believes self-medication is likely widespread in the animal kingdom.
[Source: New Scientist]