"Zombie" Fire Ants Controlled, Killed by Flies

In South America, female phorid flies have developed a bizarre reproductive strategy: They hover over fire ants ... then inject their eggs into the ants with a needle-like appendage. The egg grows and the resulting larva generally migrates to the ant's head. The larva lives there for weeks--slurping up the brain and turning the ant into a "zombie," in some cases compelling the ant to march 55 yards 50 meters away from its colony to avoid attack by other fire ants. Finally, the baby fly decapitates its host and hatches, exiting through the ant's head...

"U.S. scientists regularly release several species of phorid flies to control alien fire ants, which have spread across the southern U.S. during the past half century and outcompeted many native ant species.  Now scientists have released a new species of phorid, Pseudacteon obtusus not pictured, for the first time in the U.S., Texas A&M University announced May 11.Released in southern Texas in 2008 and eastern Texas in April 2009, P. obtusus is the first phorid released in the U.S. that is known to attack ants as they forage. In theory, feeding ants are more vulnerable to attack than those hunkering down in hidden nests.The flies—which don't have a taste for native U.S. ants—also drive the frightened fire ants into their nests, freeing up more food for the indigenous ants.It's about "leveling the playing field for native ants. We're trying to restore the balance," said Rob Plowes, a research associate at the University of Texas. Published May 14, 2009

via Pictures: "Zombie" Ants Controlled, Decapitated by Flies.

Phoridae is a family of small, hump-backed flies resembling fruit flies. Phorid flies can often be identified by their escape habit of running rapidly across a surface rather than taking to the wing. This behaviour is a source of one of their alternate names: scuttle fly. They are a diverse and successful group of insects. Approximately 4,000 species are known in 230 genera. - wiki