Ants are social creatures, and it makes sense that they look out for one another. But the extent to which they do this and the medicinal sophistication they display surprised researchers.
If African Matabele ants (Megaponera analis) go on a termite hunt, that’s a pretty cruel business. They invade a termite colony, neutralize the soldiers, and then kill the workers – stealing the eggs and nymphs for food. But the termites can fight back and injure or even kill the ants. But the Matabele ants are not only excellent soldiers, they are also excellent doctors.
Erik Frank, fresh from a postdoc program, has been on the trail of these insects since his master’s degree. Eventually he noticed that sometimes when an ant was injured, another ant would start licking the wound. He began to suspect that this was done to prevent infection and may even have used an antimicrobial. So he started following such interactions more closely.
He found that ants don’t really abandon their wounded. Instead, if an ant is wounded (and the wound is not too severe), the injured ant will remain calm and emit pheromones to inform its partners. But when an ant is badly wounded, it begins to move frantically. Essentially, the ant is signaling its situation for a diagnosis.
Better still, the injured ants are transported back to a nursery in the nest, where their infected wounds are treated.
“We are dealing here with a complex diagnostic system and a correspondingly adapted therapy,” explains Frank.
This process of diagnosis and subsequent treatment has never before been discovered in any non-human species. It is a complex process that involves diagnosing infections, deciding on a treatment, and then administering the treatment. The Matabele ants might not be the good guys in the story, but they’re certainly resourceful.
“We found that injured ants communicate when a wound is infected,” explains the biologist. “We found over a hundred chemical components and 41 proteins in the applied substances. We can already demonstrate antimicrobial properties in about half of them,” he continues.
Apparently, the ants produce the disinfectants in a gland in their thorax. This spot allows the ants to take the wounded in their mouths and suck up the substance (either from themselves, with their legs, or even from the injured comrade) and apply it to the injury
Frank now wants to look at another species of ant, the Eciton driver ant, found in Central and South America, and see if it exhibits similar behavior. This species of ants has also been observed treating their wounded, but because their raids are so long (12-14 hours) they are treated on the spot.
Longer term, Frank also suspects that the diagnosis and treatment of animals that were once thought to be exclusively human behavior may be far more widespread than we think. He wants to study this in more insects, but the behavior could also occur in other groups of animals.
“Insects are particularly suitable for observation and experimentation,” says Frank, “but such behavior could in principle be studied in all sociable animal species. For example, it has already been observed in chimpanzee mothers that they catch insects from the air, chew them up and then apply the saliva to their offspring’s wounds. It is not yet known whether the monkeys are after certain insects. However, it cannot be ruled out that they make use of the very substances that ants produce, for example, to treat wounds.”
