Ants from an African species dress the wounds of their fellow “soldiers” after their army’s fierce battles with termites, in a newly discovered behavior that researchers say is unique among insects and possibly in the entire animal kingdom.
The ants use their mouthparts to “lick” the wounds of their fellow soldiers. Researchers believe that they may be cleaning wounds and possibly treating them to prevent infection.
The survival rate of the injured ants is 20 percent without the treatment and 90 percent with it, according to the researchers from the University of Wurzburg, who published their findings in the Proceedings of the Royal Society B: Biological Sciences.
The Matabele ants, which are widely found in sub-Saharan Africa, raid termites at their foraging sites two to four times a day, forming up in long files of 200 to 600 ants, the university said in a statement.
The ants kill many termites and haul them back to the nest to be eaten. But the termites put up a fight. Well-armored, they have powerful jaws that they can use to bite limbs off the ants, the university said.
Previous research has found that when the ants are injured, they call for help by excreting a chemical that makes their fellow ants carry them back to the nest.
The researchers found that once back in the nest, the injured ants undergo “treatment,” often for several minutes.
“We suppose that they do this to clean the wounds and maybe even apply antimicrobial substances with their saliva to reduce the risk of bacterial or fungal infection,” researcher Erik T. Frank said in the statement.
Frank and his fellow researchers noticed that badly injured ants, such as those that have lost five of their six legs, flail their legs in an unsuccessful attempt to stand up, making it harder for them to get assistance. Researchers also believe that if they can’t stand up, they can’t release the rescue-signal chemical.
Less-injured ants, researchers noted, display intriguing behaviors. If they’re alone, they try to get back to the nest as quickly as possible. If other ants are nearby, however, the less-injured ants seem to barely move forward and actually fall over repeatedly, Frank said in an e-mail.
The ants appear to behave “more injured,” Frank said.
Researchers believe the ants may be making it easier for their comrades to see them, making it easier for their comrades to sense the rescue-signal chemicals, or avoiding exposure to dirt and germs. Or it might be a combination of those reasons, said Frank, now a postdoctoral researcher at the University of Lausanne.
When help finally arrives, the injured ants pull in their legs and keep still, making it easier to carry them back to the nest for treatment.
Frank said it’s possible that other ant species also exhibit the same behaviors. He said he would be taking “a closer look at potential candidate species ... so as to better understand the evolution of rescue behavior and social treatment in animals.”