'Hero' Ants Found to Face Death Alone to Save Their Colony

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The Temnothorax ant, ready to sacrifice himself. Photo via Wikipedia

It looks like action movie heroes and protagonists of Greek tragedies aren't the only ones who face death alone to save their people. Scientists have recently discovered that ants will act in a similarly altruistic fashion--when stricken with disease, the ant Temnothorax unifasciatus will abandon the colony to prevent it from spreading, and wait for death alone.The BBC reports on the scientific findings, which were just published in Current Biology. It explains that this is the first time such behavior has ever been seen in an insect. Such 'heroic' behavior has been seen in mammals, like cats, dogs, elephants, and humans, but hadn't been discovered in insects before. To study the heroism, scientists set up an experiment:

The researchers exposed a colony of Temnothorax unifasciatus ants reared in their laboratory to the spores of a lethal parasitic fungus called Metarhizium anisopliae. Most of the workers who died from the fungal infection permanently left the nest hours or days before death, and died in a foraging area far from their nest mates.

Marching off to die alone?

But that alone wasn't enough proof that the ants were acting as heroes--the fungus could simply be physically driving them away. In order to properly study the phenomenon, the scientists had to prove that diseased ants weren't jumping ship because their judgment or motor skills were affected by their sickness. So they shortened the ants' lifespan by exposing them to CO2.

Sure enough, believing that they were about to die--and free of any potentially behavior changing fungus--the ants marched off to face death alone. They weren't carried off by other ants, either, and instead left voluntarily. According to the researchers, in "choosing to face death alone, the ants were making a truly altruistic act."

It raises the interesting idea that heroism could be a genetic trait. Populations of animals willing to sacrifice themselves to protect their families would be better suited to survive than those that lacked such an instinct. So maybe the existence of Steven Seagal and Jean Claude Van Damme actually serves a genetic purpose. But maybe not.