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Mon September 12, 2011
Scientists Discover Details Of 'Kamikaze' Ants
Originally published on Mon September 12, 2011 5:52 pm
We stumbled upon a tiny report in this week's New Scientist that is so exquisitely gross, we can't help but pass it on.
In a new study published in the journal Acta Zoologica, Johan Billen of the Catholic University of Leuven (KUL), Belgium and his team report on a kind of ant that's especially evolved to kill itself in order to save the nest.
How it goes about it is the gross part: The ant of Borneo will grab on to an invading creature, and squeeze itself to death all the while releasing a lethal yellow goo.
What's odd about these ants is that they have evolved to keep a huge amount of this goo in their bodies. Normal ants have glands in their jaws that do release secretions, but these ants have filled most of their bodies with these secretions. So much so that they can't keep as much food as other ants.
We've reached out to Billen to see if we can get a bit more detail about these "exploding ants." And also to see if we can land a picture or two.
Update at 5:19 p.m. ET. Odd To Find Suicide So Far From Colony:
We were able to talk to Diana "Dinah" Davidson, one of the study's authors and a retired ecologist from the University of Utah. She was so fascinated by the ants that she paid her own way to Brunei to study the ants in the field.
We've cut this piece of audio of Davidson explaining her finds. It's a long piece, but worth a listen.
Davidson told us these exploding ants were first reported by a German biologist in the '70s. He noted that when he grabbed the ants with forceps, they would explode. He even took them back to Europe and introduced them to other ants and the result was the same: The ant would clasp on to the other ants and explode.
What Davidson and her team found was the reason for what they did. Davidson clarified that what's odd about this finding is that these ants are not directly protecting a nest, but they are protecting a foraging territory that can be "hundreds of meters from the nest."
"Organisms don't usually commit suicide," she said. Of course there are other examples, some termites and honey bees commit suicide, but Davidson explains, it's to protect a queen, which is the "reproductive individual."
"If you're going to find suicide it's not surprising to find it in social insects. It was surprsing to find it so far from the colony," said Davidson.
Of course many will say, "Well, all ants will fight to the death to protect their nest."
But Davidson said this is different. "Not all ants will blow themselves up," she said. And the way they do it means it's "intentional self sacrifice, voluntary self sacrifice."
Davidson says when an ant enters their territory they pounce.
"They grab the leg and wrap themselves around the ventral side of that opponent and when they do that the mandibular gland compound comes out through the anterior mandibular gland opening and they are forced out through pressure because the ant is squeezing itself," said Davidson.
That's right: The ant squeezes itself to death.
"They burst through the intersegmental membrane of the ant's abdomen... killing the ants," said Davidson. The ants end up "permanently glued to the opponent because the compounds are very sticky and they tumble from the canopy as a pair into the leaf litter and are eventually eaten by something."