Not just humans, even ants can perform surgery! Study reveals
A recent study published in Current Biology reveals that Florida carpenter ants perform complex surgical procedures on injured nestmates, including wound cleaning and amputation. The research shows that these ants selectively treat the limbs of their peers based on the type of injury. Erik Frank, a behavioral ecologist from the University of Wurzburg and lead author of the study, noted that this represents the only known case in the animal kingdom where one member of a species systematically amputates another.
Ants' surgical interventions boost survival rates
The study investigated two types of leg injuries in ants: femur lacerations and tibia wounds. All femur injuries were cleaned and fully amputated, while tibia injuries only received mouth cleaning. Erik Frank observed that this intervention resulted in significantly higher survival rates for ants with experimentally infected wounds. Specifically, femur injuries had a survival rate of about 90% to 95% due to amputation, whereas tibia injuries, which didn't involve amputation, had a survival rate of approximately 75%.
Treatment choices linked to infection risk
The researchers hypothesized that the choice of treatment could be associated with the risk of infection from different wound sites. Micro-CT scans revealed that the femur is primarily composed of muscle tissue, which plays a crucial role in pumping blood from the leg into the main body. An injury to this area compromises its ability to circulate potentially bacteria-laden blood. Conversely, the tibia has little muscle tissue and thus minimal involvement in blood circulation.
Ants prioritize cleaning over amputation for tibia injuries
Despite faster infection rates in tibia injuries, full amputation was not observed. This is because an ant-assisted amputation takes at least 40 minutes to complete and if not done immediately post-infection, the ant would not survive. Laurent Keller, senior author and evolutionary biologist from the University of Lausanne, explained that because ants cannot amputate the leg quickly enough to stop the spread of harmful bacteria, they spend more time cleaning tibia wounds to reduce the risk of a lethal infection.
Ants' medical system mirrors human healthcare
Frank compared this advanced behavior to human medical systems, noting that the ants' ability to diagnose a wound, assess its infection status, and treat it over time by other ants is comparable to the capabilities of human medical practices. Keller explained these behaviors are innate and change based on an individual ant's age but there is very little evidence of any learning.
Further research to explore ants' pain perception
The team is now conducting similar experiments in other Camponotus species to understand whether all ant species without a special antimicrobial gland also perform amputation. They are also exploring our understanding of pain in ant societies as ants receiving care allow for slow removal of a limb while conscious. Frank found the level of innate cooperation among ants particularly striking, especially when observing videos where an ant presents its injured leg and allows another ant to bite it off voluntarily.
Study funded by Swiss NSF, ERC, and DFG
The research into the surgical behaviors of Florida carpenter ants was supported by several organizations. The Swiss National Science Foundation (NSF), the European Research Council (ERC), and the German Research Foundation (DFG) provided funding for this groundbreaking study. This support enabled the researchers to delve deeper into understanding these unique behaviors within ant societies.
