A mind-controlling parasite turns ants into zombies, forcing them to climb to the tops of shrubs, bite and die. Now, a new study reveals that the fungus acts like a puppeteer, in a way “pulling” the muscles of the ants’ mouths.
The mind-controlling fungus passes through the ant’s exoskeleton and enters its body, where it begins to grow and spread, said lead author Colleen Mangold, postdoctoral researcher in the Department of Biochemistry and Molecular Biology at Pennsylvania State University. [Mind Control: Gallery of Zombie Ants]
The first week after being infected, the ants act normally, Mangold told Live Science. But then they start to have trouble moving and start to have muscle spasms.
“They pretty much walk aimlessly and go around in circles, or they don’t move much at all,” Mangold said. In the last stage of the disease, they find a surface and bite it off – this surface is usually the top of a shrub. After the ants die, the fungus emerges from the ant and searches for its next victim.
Mangold and his team wanted to find out what exactly was causing these ants to bite. Previous studies have shown that by the time ants bit the tops of shrubs or twigs, the fungus had already tangled around the muscles of the ants’ lower jaw, she said. But it was not clear how the fungus forced the jaws to move.
So scientists infected a handful of carpenters the ants that control the mind Ophiocordyceps Kimflemingiae mushroom. After the infected ants died, the scientists froze the ants and removed their jaw muscles and examined them under an electron microscope. At the time of death, the muscles in the mouths of the ants contracted forcefully.
How the parasite accomplishes this task remains a mystery, but they have found mysterious particles, which could potentially play a role in the fungus’ deadly grip, Mangold said. These strange particles may contain something that helps the fungus contract the muscles in the ants’ mouths, or the particles may simply be secreted by the ant to fight infection, she said. The Mangold team now hopes to find out what these particles are and if they contain anything, she added.
Surprisingly, researchers found no evidence of the fungus affecting brain cells or the connections between them. So “we don’t know how the fungus is able to impact host behavior,” she said. “We’re just starting to scratch the surface here.”
These results were published on July 17 in the Journal of Experimental Biology.
Originally published on Live Science.