A recent study has revealed a surprising behavior in ants – the ants are able to amputate the limbs of their injured companions in order to save their lives. This discovery marks the first evidence of a non-human species understanding the concept of amputation for survival.
Published on July 2 in the journal “Current Biology”, the study observed carpenter ants in Florida amputating the legs of their injured peers to increase their chances of survival.
Carpenter ants, also known as Camponotus ants, are larger in size and commonly build nests in beams, floors, or walls of buildings. The lead author of the study, ant biologist Erik Frank from the University of Würzburg, explained to NPR that the ants are not only capable of assessing the severity of their companions’ injuries but also utilize different treatment methods based on the location of the injury to maximize survival rates.
While some organisms produce antibacterial substances to apply on wounds, carpenter ants lack this gland and are territorial creatures prone to injuries during battles against intruders. This led researchers to question how these ants heal their wounds without such mechanisms.
The study found that if a worker ant’s thigh is injured, there is a 75% chance that its companions will perform an amputation procedure by licking the wound and then biting off the leg, taking an average of six minutes.
Frank mentioned to National Geographic that the ants demonstrated a surprising level of voluntary cooperation, with the injured ant extending its leg for others to amputate without resistance.
However, in cases of injuries to the lower legs, the ants do not engage in amputation. Researchers speculate that amputation might serve to prevent infection. To test this hypothesis, they conducted experiments.
Some ants were injured on their thighs or lower legs and deliberately infected, then divided into three groups to observe their survival rates: the first group of injured ants were isolated without treatment, the second group received artificial amputation, and the third group with injured ants were reintroduced to their companions.
The results showed that the isolated group of ants with thigh injuries had a 60% mortality rate, while those who underwent amputation, either artificially or by their companions, almost all survived. This underscores the effectiveness of amputation for thigh injuries in saving lives.
In contrast, ants with lower leg injuries, whether isolated or subjected to artificial amputation, had similarly high mortality rates. The experiment verified that injured ants with lower leg injuries were not amputated by their companions upon return to the colony, indicating that amputation was futile for this type of injury.
Researchers also observed that companions continuously licked the wounds of ants with lower leg injuries, resulting in a 75% survival rate for those ants, compared to only 15% for isolated ants with lower leg injuries.
The higher survival rate of amputated thigh injuries may be related to the impact of injuries on blood circulation. Similar to other insects, carpenter ants have muscles in their thigh areas that control blood flow, and thigh injuries can reduce circulation speed. This slowdown in blood circulation can impede the spread of infection, providing time for amputation and thus saving the injured ants’ lives.
Researchers additionally found that immediate amputation following lower leg injuries could enhance survival rates. This indicates that infections spread rapidly in ants with lower leg injuries.
Ant behavior expert Tomer Czaczkes from the University of Regensburg, not involved in the study, shared with New Scientist that ants understand not all injured individuals require amputation, only in justified circumstances.
This study sheds light on the remarkable behavior of ants in aiding their injured companions through amputation, showcasing complex social cooperation and survival strategies in the insect world.