May 18, 2009

Nasty Nature: Zombie Fungus

Last week in Nasty Nature, I posted about zombie fire ants -- ants infested with phorid fly larva that exhibit strange aimless wandering behavior before their heads fall off and the mature phorid fly crawls out of its mouth. Zombie-like in the behavior of their mindless wandering, it seems that ants aren't only prey to parasitic flies but also parasitic fungus that takes control of their minds.

Cordyceps is a genus of parasitic fungus that infects the bodies of its hosts. Cordyceps unilateralis can actually exert a controlling force over the brains of ants, causing them to climb to an elevated height so that when the parasitic fungal spores are ready to pop they will cover a wider area.

The whole gruesome process is beautifully captured in this clip from Planet Earth, narrated by David Attenborough: Cordyceps: Attack of the Killer Fungi

It works like this:

1.) The spores of the fungus attach themselves to the outside of the ant and germinate

2.) The germinated spores enter in to the ant's body through the ant's breathing tubes

3.) Fungal mycelia (thin filaments) invade the inside of the ant's body and consume its soft tissues without damaging the vital organs

4.) When the fungus is ready to reproduce, it grows into the ant's brain and produces chemicals that fuck with the ant's brain. By mixing up the ant's sense of perception, the fungus compels the ant to climb to a higher elevation on, for example, a plant.

5.) At the top of the plant, the ant fixes itself to the position by chomping onto the plant with its mandibles. There it sits and will die as the fungus consumes what is left of the ant's brain and then fruits out of the ant's head. Once mature, the fruiting bodies of the fungus erupt and release capsules of spores into the air which also explode and rain down parasitic zombie spores onto the other ants in the area.

Perfect idea for a gruesome zombie movie, no? Different versions of the fungus are targeted at different insects; it is only a matter of time before one adapts to infect humans! At least one person has already imagined a Cordyceps zombie. On his Science Punk Blog, Frank Swain posted a zombie identification card for a human Cordyceps zombie.

Imagine a fungus that could infect our minds and instead of driving us to a higher elevation would drive us to violent attacks to spread the deadly, mind-controlling fungus. On the other hand, zombies with mushrooms coming out of their heads might be too ridiculous for some audiences. It might remind them of the Mario games.

"Thank you Mario! But our brains are in another castle!"

Or, of Matango (Attack of the Mushroom People)

Either way, think twice before you put mushrooms on your burger today. Fungus is not your friend.