Auburn, Feb. 22 ---The mortal enemy of fire
ants has gained a toehold in Alabama.
Whether
this enemy ever manages to cause as much misery for the ants as it
does in its native habitat in South America is anyone’s guess. But
one thing’s for sure: Heads are rolling all over Alabama, and
scientists couldn’t be happier.
The pinhead-sized predator, known as the phorid fly (pictured
right), preys on the ants in the goriest manner imaginable.
After a fly lays her eggs in a fire ant, the emerging larvae makes
its way into the ant’s head and then proceeds to eat out the
inside of the head. Eventually, the head falls off and out comes a
new fly – small wonder why some people often refer to these
predators as decapitating flies.
As the new generation emerges, the ghastly cycle of
egg laying and decapitation begins again.
Phorid flies were first introduced to Alabama in
1998 as part of a regional project aimed at controlling fire-ant
populations throughout the South. The project is the brainchild of
Dr. Samford Porter, a Florida-based USDA researcher who spent years
studying the phorid fly in South America.
Curiously, the first Alabama release of phorid
flies, which took place in Talladega County in 1998, failed.
Nevertheless, Dr. L.C. "Fudd" Graham, coordinator of the
Alabama Fire Ant Management Program, Talladega County Agent Henry
Dorough, and others involved with the project pressed on with grim
determination.
Subsequent releases in Macon County in 1999 and
Lowndes County in 2001 were successful. In both cases, flies have
been spotted well beyond their points of release.
"The flies in Macon County have spread over a
10- or 11-mile radius, which totals about a 380 square-mile
area," recalls a beaming Graham.
In fact, the flies, in a manner of speaking, have
come full circle, reaching the Auburn University campus where they
were first hatched and harvested prior to their release in nearby
Macon County – a fact Graham learned while tailgating with friends
during the Auburn-Alabama game.
"Some kids with our group started asking about
the phorid flies, so we went down into the woods near campus and
began investigating some of the mounds for signs of the flies,"
he recalls with a chuckle. "And there they were."
Meanwhile, farther west in Lowndes County, the flies
have spread about 3 miles from their release point. And in Talladega
County, where Graham and Dorough first encountered so much
difficulty, the flies seem to be flourishing. Graham attributes this
to the decision to release a different kind of phorid fly, known as
Pseudacteon curvatus, which appears to be more cold tolerant and
better suited to the hybrid fire ants common in this region of the
state.
So far only one fly has been found in Houston County
following a release in fall of 2000, although Graham is confident
the flies eventually will gain a toehold.
In the meantime, Graham is planning additional
releases in Baldwin County and possibly Walker County, depending on
the availability of the flies.
Fierce as they are, phorid flies will never succeed
in wiping out fire ants entirely. Instead, they make the ants’
lives a living hell through constant attacks. Mortally frightened by
the flies, worker ants cower in their mounds and miss out on the
day-to-day foraging necessary for survival. As food sources are
depleted, fire ant populations begin dropping off.
Eventually, Graham and other experts hope to use the
flies in tandem with other control methods to keep ant populations
at manageable levels.
The flies could be the best defense yet against
imported fire ants, which escaped off a freighter in Mobile Bay more
than 60 years ago and began spreading throughout the South and
Southwest.
(Source: Dr.
L.C. "Fudd" Graham, Coordinator, Alabama Fire Ant
Management Project, 334-844-2563.)