Call an ant doctor: Amputation gives infected ants a better chance of fighting off infection.

Carpenter ants in Florida (Camponotus floridianus) They selectively treat the wounded limbs of their ant companions, according to New paper The study was published in the journal Current Biology. Depending on the location of the injury, the ants either lick the wounds clean or chew the affected limb to prevent the spread of infection. The treatment is surprisingly effective, with survival rates of around 90-95 percent for amputated ants.

“When we talk about mutilation behavior, this is the only case of sophisticated and systematic mutilation of an individual by another member of the same species in the animal kingdom.” Co-author Eric Frank said,“The fact that ants are able to diagnose a wound, know whether it is infected or sterile, and treat it accordingly over long periods of time by other individuals – the only medical system that can compete with that is the human system,” says a behavioral ecologist at the University of Würzburg in Germany.

Frank has been studying different Types of ants For many years. Late last year, he co-authored a book paper Details of how Matabele ants workMegaponera analis Sub-Saharan ants can tell whether a companion’s wound is infected, thanks to chemical changes in the hydrocarbon profile of the ant’s cuticle when the wound becomes infected. These ants only eat termites, but termites have powerful jaws that they use to defend against predators, so there is a high risk of being bitten by hunter ants.

If an infected wound is identified, the ants treat the wound with antibiotics produced by a special gland on the side of the thorax (the pleural gland). These secretions consist of about 112 components, half of which have antimicrobial properties. Experiments by Frank and others have shown that applying these secretions reduces the mortality rate of infected ants by 90 percent, and future research may lead to the discovery of new antibiotics suitable for treating humans. (This work was featured in a recent episode of a Netflix nature documentary, Life on our planet.)

These findings got Frank wondering whether the Matabele ant was unique in its ability to detect and treat infected wounds, so he turned his attention to the Florida carpenter ant. These reddish-brown ants nest in rotting wood and can be fiercely territorial, defending their homes from rival ant colonies. This fighting comes with a high risk of injury. However, the Florida carpenter ant lacks a pleural gland, so Frank and his colleagues wondered how this species treated its injured comrades. They conducted a series of experiments to find out.

Frank et al. painted samples of laboratory-reared ant colonies (produced by queens collected during fieldwork in 2017 in Florida), and targeted ants were color-marked for injury with acrylic paint 2 days before each experiment. Selective injuries were made to small leg and femur bones (such as the ankle) using sterile shears, and termite strains were cultured. Pseudomonas aeruginosa The researchers used the substance to injure some of these wounds, while leaving others intact as a control. The team videotaped the other ants’ subsequent healing behavior and analyzed the footage. They also took CT scans of the ants’ legs to learn more about their anatomical structure.