Scientists say they have discovered a horrific flesh-eating fungus which is able to infect living creatures and turn them into "zombies".

The hapless victims are then compelled to shamble away to a location where their immobilised bodies - as they are gradually consumed from within, acting as food supply and nest to the ghastly fungal offspring - can spray out more spores to seize control of more hosts.

For now, the terrifying Ophiocordyceps unilateralis fungus appears to be focusing its zombie extermination campaign primarily on carpenter ants of the sort found in the jungles of Thailand.

“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,” says Dr David Hughes of Exeter and Harvard universities.

Having successfully taken over an ant, the fungus compels it to leave its normal haunts high in the forest canopy and directs the unfortunate insect down into the dark, moist basement layers of the jungle. There the luckless creature is compelled to clamber onto the underside of a leaf in the O unilateralis' favoured location for reproduction - some 25cm above the ground, on the northwestern side of the tree or plant in question.

Once in such a location, the dying ant is made to clamp its mandibles - jaws - firmly shut onto the leaf, and then hangs lifelessly from them to become a food supply and home for the burgeoning, ghastly fungus-children within. Most of the insect's innards are gradually converted into food and consumed, but the muscles holding the mandibles shut are cunningly left alone.

In order to prevent any rivals trying to snaffle the nutritious ant corpse, the fungus also forms a protective coating or cocoon over the hanging victim. Presently a stroma or "fruiting body" sprouts from the back of the insect's head and begins to shower drifting spores down on the forest floor beneath - each of which could infect another unlucky passerby.

The fungus' dreadful capabilities were already well-known in the insect-zombification boffin community, but Hughes' latest research has revealed just how precisely the hapless walking-dead ants are controlled. He theorises that the deadly rain of mind-control zombo spores may be why the carpenter ants try to avoid the lower levels of the jungle as much as they can.

Hughes' and his colleagues' new paper, The Life of a Dead Ant: The Expression of an Adaptive Extended Phenotype, can be read by subscribers to The American Naturalist here. ®