Zombie Ants – Threat, Myth or Just Another Weird Thing?

At rgbFilter there is standing policy on providing accurate and up-to-the-minute information on one of the major cultural memes of our times; Zombies. Yes, for other news outlets the Zombie thing is like so  ’07 but here at rgbFilter we know that the undead never sleep and vigilance must never tire. Towards this end we present not just the cultural manifestations of the Zombie Menace but probable vectors of infestation from current research in various fields of science.

It started innocently enough these things always do. This reporter was scanning the Interweb for breaking stories (and avoiding working on his 2003 Tax Return) by checking leads at one of his favorite websites 3 Quarks Daily. There amidst the usual weighty articles (Are William T. Vollman’s Novels More Overrated Than Thomas Pynchon’s? Just How Big a Nazi was Martin Heidegger?…etc.)  this little  item jumped out…

ATTACK OF THE ANCIENT ‘ZOMBIE’ ANTS

The link lead to an article published in Nature which detailed how paleobotanists had  deduced that certain markings on fossilized leaves where probably bite marks left by “zombie ants”. It was a feel good story for the everything connects crowd but I needed more.  Zombie Ants; what are they?

It goes like this. In the forests of Thailand, a species of carpenter ant  (Camponotus leonardi) builds their colonies high in the canopy and  forage for food on the forest floor. A parasitic fungus (Ophiocordyceps unilateralis) is able to infect the ants and apparently take control of them.

An ant,  under the control of the fungus, will then proceed to areas of the forest that are best for fungus growth. In this case, the underside of leaves at 25 centimetres above the ground at a north west facing; yes it is that specific. The ant makes it to the spot, clamps its mandibles in a final “death bite” into the target leaf’s main vein and then expires.

The fungus goes to work harvesting the victim’s innards for nutrients and preserving the exoskeleton to act as a shell for itself. Despite the many changes going on inside the  dead ant’s body, the fungus leaves the muscles controlling the mandibles intact so that the corpse stays in its optimal spot on the leaf. Eventually a “fruiting stalk” sprouts from the back of the ants head and ejects fungal spores into the air. These spores then go on to infect other ants.

A feast of gruesome images and trunk load of philosophical questions. How does the fungus control the ant? How did these  “novel exploitation strategies” (to quote the abstract for the original paper in The American Naturalist) develop? People who say the Theory of  Evolution is just a theory will of course see another irreducible complexity or  the hand of God  but here  it’s more like tentacles and his name is Cthulu: these fungi are channeling very heavy Old One ju-ju. For people who “get” evolution an interesting sidebar is that the zombie-ant might be an example of Richard Dawkins’ “extended phenotype”. This model has the phenotype considered not just as genes “in-the-body” but behavior as well. As Dawkins puts it:

An animal’s behavior tends to maximize the survival of the genes “for” that behavior, whether or not those genes happen to be in the body of the particular animal performing it.

Taking over someone’s body to get something done strikes me as an extreme example of that.

As a possible trigger for a Zombie Apocalypse I’d have to say it’s pretty low probability-wise.  Ophiocordyceps unilateralis had millions of years to hack the carpenter ant. Don’t expect human fungal zombies any time soon. But as yet another excuse for yet another zombie movie? Any day now.