Fire ant lab celebrates 20 years of research

AUSTIN, Texas—The red imported fire ant laboratory at The University of Texas at Austin Brackenridge Field Lab (BFL) is celebrating 20 years of research this month.

Dr. Larry Gilbert, director of BFL and professor of integrative biology, first initiated fire ant research at the university in 1986 by bringing to the university two young researchers, Sanford Porter and Ed Vargo, dedicated to the study of the invasive ants. Gilbert’s goal was to establish a program devoted to understanding how to control the ants without the use of pesticides.

Since 1986, numerous scientists and students have been involved in the program and great strides have been made.

“Thanks to the availability of BFL near campus and the research talent attracted to UT-Austin, we now know many details of this fascinating system,” says Gilbert. “Moreover, a large group of fire ant researchers, including undergraduate and graduate students, were inspired by being at BFL or have been influenced by those who were.

“This army is too large to name all the individuals, but each member of the team was absolutely critical to the success of the venture to date.”

One of the largest success stories of the fire ant research lab has been the discovery and introduction of a parasitic fly that targets and controls imported fire ant populations. The fly larvae develop inside the ants and kill their host. BFL researchers also found that when the flies are buzzing around, the imported ants stay inside their nests to avoid being attacked. This lessens their ability to collect food and grow the colony.

When the BFL fire ant project was initiated 20 years ago little was known about the phorid flies. Gilbert and his colleagues brought the flies from Brazil and Argentina and have since engaged in many studies and release programs with them.

“This was the first place that the U.S. Department of Agriculture granted permission to release phorids for North America,” says Gilbert. “The first attempt to initiate naturalized populations of exotic phorids anywhere in the world took place at BFL in late 1995.”

Research at the fire ant lab has also shown that:

• Texas has denser fire ants populations than other states,

• Colonies of ants with multiple queens (like those in Texas) can reproduce by budding and can achieve higher densities,

• Red imported fire ants negatively affect native arthropods, including native ants; and,

• Central Austin contains the largest number of native fire ants so far discovered within the continuous distribution of red imported fire ant in the U.S.

In 2005, scientists at the fire ant lab trained ranchers in Bee County, Texas to dig up fire ant mounds, separate the ants and transport them to areas where naturalized phorid flies could attack them. The method led to the first successful introduction of a phorid fly in South Texas and inspired a new approach to establishing the flies south of San Antonio.

Fire ant research continues at BFL with scientists using new remote sensing and Geographic Information System technology to better understand the colonization of fire ants and the spread of the phorid flies. The fly’s range now extends to over more than 3.5 million acres in Texas.

Using molecular genetic techniques, researchers in the lab have also found that a species of phorid fly previously thought to be one species is in fact two. The laboratory has studied attack behavior and host specificity in more that 10 phorid fly species known to attack the red imported fire ant in its South American home and is searching for even more potential ant-controlling fly species with Argentine and U.S. Department of Agriculture (USDA) collaborators.

To learn more about fire ant research at the university, visit http://uts.cc.utexas.edu/~gilbert/.