Some ants chomp off the contaminated limbs of nestmates to spice up their possibilities of survival, making them the one recorded non-human animals to carry out amputations to save lots of one other’s life.

We already knew that ants are one of many few animals that are likely to the accidents of their friends. Matabele ants (Megaponera analis), for instance, can deal with infections by secreting an antimicrobial substance produced by particular glands.

However not all ant species have these glands, says Erik Frank on the College of Würzburg in Germany. “We needed to seek out out what occurs with ants that can’t use antibiotics.”

Whereas intently observing colonies of Florida carpenter ants (Camponotus floridanus) within the laboratory, Frank’s colleague Dany Buffat on the College of Lausanne, Switzerland, noticed an ant chewing off a nestmate’s wounded leg.

“I didn’t consider them at first,” says Frank. “I assumed there should be one thing else occurring. Possibly there was a menace, or the ant thought they have been attacking an enemy.”

After analysing video footage of the colonies, the staff noticed much more incidences of amputation. Every time, the amputee confirmed no indicators of wrestle. What’s extra, these amputations solely occurred when the damage was on a person’s higher leg.

To be taught extra, the staff gave thigh accidents and infections to 72 carpenter ants. Half of the ants acquired leg amputations from the researchers, whereas the others have been left as a management. The mortality charge of amputees was 90 per cent decrease than within the management group, which suggests these procedures efficiently stopped the pathogen from spreading.

In distinction, amputations by different ants by no means occurred if the wound was on an ant’s decrease leg, and when the staff repeated the experiment with decrease leg accidents, the mortality charge was the identical for each the amputees and the management group. This might be right down to ant physiology, says Frank. “Bugs don’t have a central coronary heart like we do,” he says. As a substitute, a number of muscle tissues pump blood across the physique, and through the use of micro-CT scans, the staff discovered that many of those muscle tissues are concentrated within the higher legs of carpenter ants.

Meaning higher leg amputations harm blood-pumping muscle tissues, stopping blood from circulating and spreading infections. However, for the reason that decrease legs lack these muscle tissues, amputating them doesn’t cease the unfold.

“The discovering is outstanding and pushes the envelope of our understanding of behavioural immune techniques in social bugs,” says James Traniello at Boston College in Massachusetts.

Tomer Czaczkes on the College of Regensburg in Germany is shocked at simply how focused the amputation is. “They don’t simply deploy blanket amputation on any damage – they solely accomplish that when it could make sense.”

“It appears unlikely that the ants have an understanding of the last word causes for why these amputations work. More likely is that that is an innate behaviour, which the ants are ‘born’ with,” he says.