Ants are the first non-human surgeons – Technologist

The Covid-19 pandemic killed over 20 million people worldwide and disrupted the global economy. But for researcher Erik Frank, the virus had an unexpected consequence. A specialist in the health behavior of ants, the young German researcher – then a post-doctoral fellow at the University of Lausanne (Switzerland) – could no longer travel to Côte d’Ivoire to study his favorite species, the Matabele ant, famous for its raids on termite colonies. “I was forced to adapt and changed my questions so that I could work on the ants we had available at the laboratory in Lausanne.” It was a change of approach with spectacular results. In the July 2 issue of the journal Current Biology, the biologist from the University of Würzburg (Germany) and his colleagues announced “the first case of a medical amputation in the animal kingdom.”

The carpenter ant from Florida is the first to have obtained this diploma in non-human surgery. It’s a rather ordinary insect at first glance. Neither very large (1.5 centimeters) nor very colorful (brown), it is conventional in its diet and not particularly aggressive. It does, however, have one peculiarity: the absence of a metapleural gland, the organ which, in most ant species, enables production of antimicrobial compounds. “So, how does it treat wounds?”

To answer this new question, Frank asked his student Dany Buffat to observe the behavior of these ants with their injured fellow creatures, “with no particular expectations,” he swore. “When he told me that they amputate damaged legs, I didn’t believe him at first,” Frank admitted. “He showed me the videos. It was indisputable! And the way the amputated individuals seemed to cooperate, really impressive.”

New questions

The researchers first wanted to know whether the location of the wound was important. So they wounded ants themselves, some on the femur, others on the tibia, and returned them to their colony. In both cases, the ants first cleaned the wound with their saliva. But they then amputated 76% of the first group within three hours, dutifully sawing off the trochanter joint at the base of the leg. Nothing like that for the second group, just reinforced cleaning.

Why such a difference? Scientists compared injured ants subjected to an infectious agent, depending on whether or not they had undergone amputation. When the wound was located on the femur, 60% of untreated ants died. In contrast, over 90% of those who experienced amputation by the researchers or their fellow ants survived, as did the control group of injured but uninfected ants. There was nothing similar with the shin wounds. This time, it was the individuals isolated after infection or undergoing amputation after one hour that perished en masse. Conversely, infected ants treated in the colony (i.e. without amputation) survived in the main, as did uninfected ants.

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