May 13, 2009

Nasty Nature: Zombie Fire Ants

I came across an interesting story in the Star-Telegram by Bill Hanna yesterday called "Parasitic flies turn fire ants into zombies"

The article focuses on the phorid fly of South America. The fly will attack only red imported fire ants for the purpose of implanting its egg in the ant. It divebombs an ant and inserts an egg in the ant's midsection. Once the egg is laid and hatches, the maggot moves through the ant's body and worms its way into the ants head and eats its brain. The maggot develops into an adult fly inside the ant's head, which soon falls off. Then the fly crawls out the ant's mouth.

We could call the ants "zombies" because of their strange ambulatory behavior once infested:

"At some point, the ant gets up and starts wandering," said Rob Plowes, a research associate at UT [University of Texas].

The maggot eventually migrates into the ant’s head, but Plowes said he "wouldn’t use the word 'control’ to describe what is happening. There is no brain left in the ant, and the ant just starts wandering aimlessly. This wandering stage goes on for about two weeks."

About a month after the egg is laid, the ant’s head falls off and the fly emerges ready to attack any foraging ants away from the mound and lay eggs.

Phorid flies can be bought and sold as a means of pest-control to reduce the spread of fire ants and control their movements.

The whole grisly life cycle of the phorid fly reminds me of the wasps in Dead Rising except the zombies don't lose their heads until you kill the Queen Wasp.