Zombie ant fungus: four species not one

MIND CONTROL: A zombie ant fungus sprouts from an ant's head

March 2011: A bizarre so-called zombie ant fungi which takes control over the minds of ants before killing them and sprouting from the insects' heads, has been found to be four separate species, rather than the one originally thought.

The four species, which infect carpenter ants in the Brazilian rainforest, have been discovered and described by David Hughes and Harry Evans, after they noticed a range of different looking fungi emerging from ants' heads.

The fungus can infect an ant, take over its brain, and then kill the insect once it moves to a location ideal for the fungus to grow and spread their spores.

‘It is tempting to speculate that each species of fungus has its own ant species that it is best adapted to attack,' Hughes said. ‘This potentially means thousands of zombie fungi in tropical forests across the globe await discovery.'

'The fungus makes ants travel a long way in the last hours of their lives'
In a parasitic death sentence worthy of a B-movie horror story, the fungus turns carpenter ants into the walking dead, gets them to die in a spot that's perfect for the fungus to grow and reproduce. 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 Hughes.

After the ant dies, the fungus continues to grow inside it. Hughes and colleagues found that the parasite converts the ant's innards into sugars that help the fungus grow. But it leaves the muscles controlling the mandibles intact to make sure the ant keeps its death grip on the leaf. The fungus also preserves the ant's outer shell, growing into cracks and crevices to reinforce weak spots, creating a protective coating that keeps microbes and other fungi out.

Scientists have yet to discover how they exert such control over their hosts.