I first heard about zombie ants on a Radiolab podcast. A fungus infects the ants and changes their behaviour to suit its needs.
Scientists have no clue how the fungus takes control of the brains of ants so effectively. But a new study in the September issue of the American Naturalist reveals an incredible set of strategies that ensue.
The carpenter ants nest high in the canopy of a forest in Thailand, and they trek to the forest floor to forage. The fungus, Ophiocordyceps unilateralis, prefers to end up on the undersides leaves sprouting from the northwest side of plants that grow on the forest floor, the new study showed. That’s where temperature, humidity and sunlight are ideal for the fungus to grow and reproduce and infect more ants.
Once infected by the fungus, an ant is compelled to climb down from the canopy to the low leaves, where it clamps down with its mandibles just before it dies.
“The fungus accurately manipulates the infected ants into dying where the parasite prefers to be, by making the ants travel a long way during the last hours of their lives,” said study leader David P. Hughes of Harvard University.
You can read more about zombie ants at Live Science here.