MonsterTalk had probably its most science-related, as opposed to the pseudoscience it trades in, and creepy discussions in its latest episode. And, Svengali fungus compelling unwitting ants to become fungus nurseries is only half the horror.
“The behavior of these infected zombie ants essentially causes their bodies to become an extension of the fungus’s own phenotype, as non-infected ants never behave in this way,” said David P. Hughes, the first author of the research paper and an assistant professor of entomology and biology at Penn State University.
Using transmission-electron and light microscopes, the researchers were able to look inside the ant in order to determine the effect of the fungus on the ant. They found that the growing fungus fills the ant’s body and head, causing muscles to atrophy and forcing muscle fibres to spread apart. The fungus also affects the ant’s central nervous system. The scientists observed that, while normal worker ants rarely left the trail, zombie ants walked in a random manner, unable to find their way home. The ants also suffered convulsions, which caused them to fall to the ground. Once on the ground, the ants were unable to find their way back to the canopy and remained at the lower, leafy understory area which, at about 9 or 10 inches (25 cm) above the soil, was cooler and moister than the canopy, provided ideal conditions for the fungus to thrive.
The scientists found that at solar noon, when the Sun is at its strongest, the fungus synchronised ant behavior, forcing infected ants to bite the main vein on the underside of a leaf. The multiplying fungal cells in the ant’s head cause fibres within the muscles that open and close the ant’s mandibles to become detached, causing “lock jaw,” which makes an infected ant unable to release the leaf, even after death. A few days later, the fungus grows through the ant’s head a fruiting body, a stroma, which releases spores to be picked up by another wandering ant.
“The fungus attacks the ants on two fronts: first by using the ant as a walking food source, and second by damaging muscle and the ant’s central nervous system,” Hughes said. “The result for the ant is zombie walking and the death bite, which place the ant in the cool, damp understory. Together these events provide the perfect environment for fungal growth and reproduction.”
The really horrific aspect of this zombification is, that ants, one of the most sociable of animals, through the fungus’ machinations, become loners suffering not only a wasting death, but are also isolated from the community. It’s not like as if the infected ants could be inserted into a colony, because other ants would instantly destroy the threat, and the fungus would lose its factory. So, part of the zombie process is self-exile, compelled by the fungus acting on the nervous system.
Now, I really hate Athlete’s Foot.