With their incredible intelligence and organisational skills, it’s no secret that ants are one of nature’s smartest insects.
But a new study shows that their capabilities even extend to performing life-saving operations on their peers.
Researchers have found that ants carry out procedures on nestmates to save them from infections and potential death.
Remarkable video shows healthy ants helping out friends who have a leg injury, either by wound cleaning or amputation.
Ants can survive with one leg or even two legs missing, although their ability to transport leaves, twigs or food is impaired.
Lab experiments show that Florida carpenter ants treat the wounded limbs of fellow nestmates – either by wound cleaning or amputation (pictured)
The new study was led by Dr Erik Frank, a behavioral ecologist from the University of Würzburg in Germany, and published in Current Biology.
‘The fact that the ants are able to diagnose a wound, see if it’s infected or sterile, and treat it accordingly over long periods of time by other individuals – the only medical system that can rival that would be the human one,’ Dr Frank said.
He and colleagues specifically studied Florida carpenter ants (Camponotus floridanus), a common, brown species native to the southern US state.
In labs at the University of Lausanne in Switzerland, the researchers cut selected ants on their right hind limb, leaving them at risk of infection.
The team observed the behaviours of their nestmates for about a week, while filming them up-close.
They found that nestmates would either perform wound cleaning with just their mouthparts, or do cleaning followed by the full amputation of the leg.
Two carpenter ants, Camponotus fellah, are seen in this undated photograph in a lab at the University of Lausanne in Switzerland. The ant on the right is licking the wounds on an injured leg of the other ant
The research team found the ants’ choice of care catered to the type of injury presented to them. Here, the ant on the right is caring for the leg wound of the one on the left
Amazingly, the ants appeared to assess the injury to decide which procedure to perform, like a trained doctor assessing a patient.
When an ant’s leg was injured at a leg segment called the femur, nestmates amputated the leg by biting it off.
But when the injury was in the tibia, a segment further from the body, the insects focused instead on mouth cleaning.
In both cases, the nestmate intervention resulted in ants with infected wounds having a much greater survival rate.
Femur injuries, where they always amputated the leg, had a success rate around 90 per cent or 95 per cent.
For the tibia, where they did not amputate, it still achieved about the survival rate of 75 per cent.
‘This is in contrast to the less than 40 per cent and 15 per cent survival rate for unattended infected femur and tibia abrasions, respectively,’ said Dr Frank.
It’s thought the preferred path of wound care could be related to the risk of infection from the wound site.
Micro-CT scans of the femur showed it is largely composed of muscle tissue, suggesting it plays a big role in pumping blood to the rest of the body – and so the risk of a lethal infection from a femur injury is likely higher.
This graphical abstract shows amputation and wound care behaviour in Florida carpenter ants (Camponotus floridanus)
Ants are regularly described as the most intelligent of all insects and might even possess some level of self-awareness.
But the researchers think the ability to help a nestmate comes naturally and is a ‘innate behaviour’.
‘Ant behaviours change based on the age of an individual, but there is very little evidence of any learning,’ said senior author Laurent Keller at the University of Lausanne.
Wound care among ants is not an entirely new phenomenon; a 2023 study found a different species, Megaponera analis, use a special gland to inoculate injuries with antimicrobial compounds meant to quell possible infections.
But the authors of this new study say Florida carpenter ants are special because they have no such gland, and so use only mechanical means to treat their nestmates.
‘When we’re talking about amputation behavior, this is literally the only case in which a sophisticated and systematic amputation of an individual by another member of its species occurs in the animal kingdom,’ said Dr Frank.
