Zombie fire ants

Brains. [Link]

The tool is the tiny phorid fly, native to a region of South America where the fire ants in Texas originated. Researchers have learned that as many as 23 phorid species along with pathogens attack fire ants to keep their population and movements under control.

So far, four phorid species have been introduced in Texas, where fire ants cost the economy about $1 billion annually by damaging circuit breakers and other electrical equipment, according to a Texas A&M study. They can also threaten young calves.

The flies “dive-bomb” the fire ants and lay eggs, and then the maggot that hatches inside the ant eats away at the brain. Later, the ant gets up and starts wandering for about two weeks, said Rob Plowes, a research associate at the University of Texas at Austin.

Although the ant exhibits zombie-like behavior, 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.”

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

Plowes said fire ants are “very aware” of these tiny flies, and it only takes a few to cause the ants to modify their behavior.

“It’s kind of like a medieval activity where you’re putting a castle under siege,” Plowes told the Fort Worth Star-Telegram for a story in Tuesday editions.