AUSTIN, Texas -- Parasitic flies introduced to control red imported fire ants have spread over four million acres in central and southeast Texas since the flies' introduction in 1999, researchers at The University of Texas at Austin have discovered using new flytraps they developed.

Researchers at the Brackenridge Field Laboratory (BFL) have released multiple species of the parasitic flies, originally from Brazil and Argentina, to control invasive fire ants without pesticides. The fly larvae develop inside the ants and kill their host.

Dr. Ed LeBrun, a researcher at BFL, developed the new flytraps that allowed him to map the spread of the first species of phorid fly successfully introduced. The fly, Pseudacteon tricuspis, was introduced to several locations in Texas beginning in 1999 with BFL in central Austin.

The small traps capture fire ants first by luring them in with ants from a disturbed mound. The flies follow the ants into the traps and then become stuck on strips of flypaper when they take a break from attacking their victims. Researchers place traps around fire ant mounds along roads and analyze the flies they catch.

They have found the introduced phorid flies attacking imported fire ants in more than 12 counties and 3.5 million acres in Central Texas and seven counties and 1.5 million acres in the Coastal Bend region of Texas.

Phorids got a slow start after introduction due to drought in Texas from 1999-2001, says Dr. Larry Gilbert, director of the fire ant research program and professor of integrative biology, but they are now spreading three-to-10 miles per year from initial introduction sites.

In addition to Brazilian and Argentinean strains of P. tricuspis, two other phorid species were introduced since 2004, and Gilbert says the smallest one, P. curvatus, is also on the march.

Gilbert says these initial successes should be seen as "getting to first base" in the attempt to cont
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Contact: Larry Gilbert
lgilbert@mail.utexas.edu
512-471-4705
University of Texas at Austin
27-Sep-2006