Humans aren’t the only animals that try to heal wounds, or even resort to amputation surgery. Some carpenter ants appear to treat wounds in their nestmates by cleaning them or amputating limbs, and may even tailor their treatment to the type of wound. The study was published in the journal Nature on July 2. Current Biology And observed in the video above.
“When it comes to cutting behavior, this is literally the only case in the animal kingdom where we see one individual cutting another so cleverly and systematically,” says study co-author Eric Frank, a behavioral ecologist at the University of Würzburg. It said in a statement.
In ants, wound cleaning is not species specific. Megaponera analis Ants use specialized glands to deliver antibacterial compounds to stave off potential infection. However, the Florida carpenter ants in this new study do not have these types of glands and appear to use only mechanical means to treat their fellow ants. This treatment involves one of two methods. In the first method, the ants clean the wound with their mouthparts, but do not use the antibiotic-like secretions that other ants have. In the second method, they clean similarly to the first method, but then use their mouths to completely remove the affected area. To determine which method is best, the insects appear to assess the type of damage.
In studyThe team analyzed two types of leg injuries: femur lacerations and ankle-like tibia injuries. All femur injuries were first accompanied by cleaning of the cut wound by a nestmate, who then bit the leg off completely. Tibia injuries involved only mouth cleaning. In both cases, the ants with experimentally infected wounds Survival rates are much higher.
[Related: Matabele ants might be able to diagnose and treat infected wounds.]
“With femur injuries, we always amputated the leg, but the success rate was about 90 to 95 percent. And with the tibia, which we didn’t amputate, it was still about [a] “The survival rate is 75 percent,” Frank says. This contrasts with survival rates of less than 40 percent and 15 percent for neglected, infected femur and tibial abrasions, respectively.
The research team believes that the preferred method of wound care may be related to the risk of infection from the wound site. Micro-CT scans of the femur revealed that it was mostly composed of muscle tissue. Muscle tissue is what causes the femur to grow. HemolymphThe femur plays a functional role in pumping blood from the leg to the trunk. Damage to the femur can lead to muscle damage and reduced ability to circulate blood contaminated with bacteria. However, the tibia has little muscle tissue and therefore plays little role in blood circulation.
“Injuries to the tibia leave the hemolymph flow less impeded, allowing bacteria to enter the body more quickly, whereas injuries to the femur slow down blood circulation in the leg,” Frank said.
Crested Finch Ants can use their mouthparts to cleanse wounds. Credit: Danny Buffat.
Initially, it seemed likely that if tibia damage would hasten infection, amputating the entire leg would be the most appropriate treatment. However, the team actually observed the opposite: the speed at which the ants amputate the leg is important, with ant-assisted amputation taking at least 40 minutes. In the case of tibia damage, the team found that if the leg is not amputated soon after infection, the ants will die.
“So because the ants cannot cut their legs fast enough to prevent the spread of harmful bacteria, they try to limit a potentially fatal infection by spending more time cleaning the shin wound,” says study co-author Laurent Keller, an evolutionary biologist at the University of Lausanne. It said in a statement.
According to the teamThe fact that these insects can diagnose wounds, check for infection, and treat them makes it “the only medical system that can rival the human medical system.”
Given the sophisticated nature of these behaviours, a logical next research direction would be to understand how these ants are able to perform such precision care.
[Related: Invasive ants leave lions scrambling for prey on the savannah in an ecological chain reaction.]
“This is all innate behavior,” Keller says. “The behavior of ants changes with age, but there is little evidence of learning.”
The team is currently conducting similar experiments in other regions. Camponotus seed “We will investigate how conserved this behaviour is to understand whether amputations are also performed by all ant species that do not have specialised antibacterial glands. As cared-for ants are also able to slowly amputate limbs while conscious, the team hopes to further our understanding of pain in ant societies.”
“An ant holds out its injured leg and allows another ant to bite it off, completely of its own accord, and then shows the new wound to the other ant. [the] “This level of natural cooperation during the cleaning process is very impressive to me,” Frank said.
