Texas Imported Fire Ant Research and Management Plan1997-98 Progress Toward Lessening the Sting of the Fire Ant Problem

Texas Imported Fire Ant Research and Management Plan, November 1998

During the first year of funding, participants of the Texas Imported Fire Ant Research and Management Plan have made great strides in the fight against imported fire ants. They have educated thousands of Texans about gaining short-term relief from these pests with current methods and products, and researchers have made exciting scientific discoveries for more permanent, natural ways to control the insect.

Texas Agricultural Experiment Station
Texas Agricultural Extension Service
Texas Department of Agriculture
Texas Parks and Wildlife Department
Texas Tech University
University of Texas

Research

There is not one sure-fire way to control fire ants -- it's going to take collective use of a variety of natural enemies and products developed from the findings of basic research.

Finding Natural Enemies

Researchers from the Texas Agricultural Experiment Station, Texas Tech University and the University of Texas have identified potential natural threats to imported fire ants and are further investigating to see if they will be feasible in controlling fire ants in Texas.

The flies from Brazil. This past year, University of Texas researchers have imported, mass produced and made an initial release in Austin and Laredo of one species of phorid fly, a parasitic fly native to Brazil that is a natural attacker of the imported fire ant. This particular phorid species, however, primarily attacks fire ants when their mounds are disturbed. Researchers have also identified species that attack fire ants while they are foraging during the day. By using multiple phorid fly species to disrupt imported fire ants' foraging, other native ant species can better compete with the fire ant for food and can better defend their territories, thus limiting the spread of fire ants.
(Larry Gilbert, University of Texas, 512/471-4705, lgilbert@mail.utexas.edu)

A fatal fungus. Texas Tech researchers have formulated a fire ant bait from a strain of a fungus (Beauveria bassianna). Field studies conducted this year found the fungus to be highly effective in killing imported fire ants. To see if the fungus bait formulation is responsible for killing ants, they have genetically altered the fungus to include an enzyme that will indicate the presence of the fungus in dead ants. Researchers are also working on incorporating toxic genes of the straw itch mite, found to be harmful to fire ants, into the fungus as well.
(Harlan Thorvilson, Texas Tech University, 806/742-2828, rthgt@ttacs.ttu.edu)

A disease to please imported fire ant haters. Scientists at Texas A&M have identified an organism (Thelohania solenopsae) that causes a devastating disease in imported fire ants. Researchers found that a different strain may affect native fire ants. They are now developing ways to grow and release this organism for field trials.
(Brad Vinson, Texas Agricultural Experiment Station, 979/845-9754, b-vinson@tamu.edu)

The attack of the killer parasite. A Texas A&M scientist conducted field surveys of what was generally thought of as a rare parasite (Strepsiptera) of the imported fire ant. He found that the creature wasn't so rare -- more than 50 percent of the worker ants surveyed contained the male form of the parasite.
(Brad Vinson, Texas Agricultural Experiment Station, 409/845-9754, b-vinson@tamu.edu)

Bolstering Native Ant Populations
Biological control agents being evaluated are not expected to eradicate the red imported fire ant, either alone or collectively. However, if successfully introduced and maintained, these natural enemies are hoped to weaken imported fire ant colonies. As a result, other Texas ant species would better compete with the imported fire ant for food and resources, thus reducing fire ant populations.

The best ant competitors. Texas A&M researchers have found five Texas ant species that can successfully eliminate small red imported fire ant colonies.
(Brad Vinson, Texas Agricultural Experiment Station, 409/845-9754, b-vinson@tamu.edu)

Highlights

  • University of Texas researchers have made an initial release of one phorid fly species and for the first time have captured them "attacking" fire ants on slow motion video.
  • Texas Tech scientists completed field studies of a fungus that shows to be highly effective in killing fire ants. They have genetically marked the fungus so they can track it in ant colonies.
  • Texas A&M researchers have discovered that reproductive control in multiple queen colonies and single queen colonies differ. This means different management methods need to be devised for each type.

Where are the natives? Scientists at the University of Texas are assessing the distribution of native ant species where phorid flies are released and are developing monitoring techniques.
(Larry Gilbert, University of Texas, 512/471-4705, lgilbert@mail.utexas.edu)

I.D. required, please. Researchers at Texas A&M are developing an illustrated guide to help the public identify ant species in Texas. This guide is important because not treating for native ants may be a way to reduce the further spread of imported fire ants.
(Brad Vinson, Texas Agricultural Experiment Station, 409/845-9754, b-vinson@tamu.edu)

Why Fire Ants Do What They Do

In order to develop new environmentally friendly products to manage fire ants, researchers must understand what makes fire ants tick in terms of nutritional intake, reproduction, and communication. Then they can replicate the hormones and chemicals of fire ants to hinder behaviors such as reproduction, communications, and foraging to reduce the negative impact of fire ants on wildlife, electrical equipment, and agricultural concerns.

Birth control fit for a queen. Researchers at the University of Texas are studying the chemical signals (pheromones) that are produced by queens -- one that attracts workers to the queen and one that inhibits young queens from reproducing in the colony. They have documented when and where these substances are secreted as the queen matures and are determining the chemical composition of the queen attractant.
(Larry Gilbert, University of Texas, 512/471-4705, lgilbert@mail.utexas.edu)

Reproduction in single queens differs from queens that cohabitate. Reproductive control in multiple queen colonies and single queen colonies seem to differ. This means different methods need to be devised to manage each type of colony. Texas A&M scientists have developed a method to determine the dominance hierarchy of queens in the same colony. Their studies so far have shown that subordinate queens that associate with the dominant queen have increased body weight as well as egg production. Preliminary studies on single queens indicate that light, food, and especially temperature play a key role in body weight and egg production.
(Brad Vinson, Texas Agricultural Experiment Station, 409/845-9754, b-vinson@tamu.edu)

Love in the afternoon. Texas A&M researchers have developed a way to induce imported fire ants to go on mating flights. Preliminary studies of these flights show that they occur at predictable times of the day, usually late morning, early afternoon. They also found that the males fly first, with females following 15 to 30 minutes later, and that the temperature must be 75 to 90 degrees and the relative humidity be more than 80 percent before the ants will mate.
(Brad Vinson, Texas Agricultural Experiment Station, 409/845-9754, b-vinson@tamu.edu)

Killing larvae. Texas Tech researchers have analyzed the venoms of more than 500 fire ant workers and queens at various maturity levels. Fire ants not only sting humans and animals but other fire ant queens, workers and larvae. They have discovered a population of fire ants with unusually high levels of toxins in their venom, and are closer to finding the circumstances when fire ants execute their own larvae.
(Richard Deslippe, Texas Tech University, 806/742-2690, cmrjd@ttacs.ttu.edu)

Shutting down egg production. Researchers at the University of Texas are refining the method for measuring a major hormone called the juvenile growth hormone, which regulates reproduction in fire ants as well as other insects. They have also discovered that the initiation of egg development and secretion of queen chemical signals (pheromones) is tightly synchronized, which suggests that the same factors are responsible for reproductive development and pheromone production.
(Larry Gilbert, University of Texas, 512/471-4705, lgilbert@mail.utexas.edu)

HIGHLIGHTS

  • By developing a way to induce fire ants to go on mating flights inthe lab, Texas A&M researchers found that the flights usually occur in late morning/early afternoon and that it must be 75 to 90 degrees F. and 80% humidity before the ants will mate.

  • A UT-San Antonio researcher has completed a detailed survery of fire ant antennae. This will help idenitfy the chemicals fire ants can detect - a key in formulating new baits and repellents.
  • Texas Tech scientists have analyzed the venoms of more than 500 fire ant workers and queens and have discovered a population of ants with higher levels of toxins in their venom. This is an important discovery because ants also sting other ants and venom could be used in developing new products.

Disrupting mating. A Texas A&M researcher is also studying the role the juvenile growth hormone may have in causing un-mated fire ant queens to drop their wings, which normally occurs after a mating flight and which triggers egg production. His studies are the first to investigate fire ants at the tissue and molecular levels to identify how the hormone regulates this phenomenon. Once this is understood, it should be feasible to formulate a strategy for disrupting fire ant reproduction.
(Larry Keeley, Texas Agricultural Experiment Station, 409/845-9727, LLKeeley@tamu.edu)

Making sense of fire ants' antennae. A UT-San Antonio scientist has completed a detailed survey of the sensory structures on the antennae of fire ant workers and males. Understanding the structure and electrical response of their antennae to odors will help identify a wide variety of chemicals and mixtures that fire ants can detect. The results will be useful in formulating baits and repellants they will not avoid. (Robert Renthal, UT-San Antonio, 210/458-5452, rrenthal@utsa.edu)

Blocking the nutrition intake process. Scientists at Texas A&M are finding ways to prevent fire ants from absorbing nutrients they eat. They are determining the structures of enzymes crucial to this function, which will help in the development of products that will inhibit nutrient absorption. (Edgar Meyer, Texas Agricultural Experiment Station, 409/845-1745, Meyer@bioch.tamu.edu)

Going for the nerve. Texas A&M researchers have discovered the protein receptors that mediate nerve transmitters and hormonal functions in imported fire ants. With this discovery, scientists are now designing molecules to interfere with the ant's critical physiological processes, thus leading to a novel insecticide for fire ant management. (Patricia Pietrantonio, Texas Agricultural Experiment Station, 409/845-1744, p-pietrantonio@tamu.edu)

Deliverable Technologies

This activity involves taking promising information and technology from research and developing and evaluating the best methods and products for its application and use.

Two new bait products approved for agricultural lands. As a result of applied research conducted by the Texas Agricultural Extension Service, the first baits approved for agricultural lands will be introduced in the marketplace by early 1999. One product will be registered for use in pastures and crop land and the other will be for use in turf grass and nursery crops. Both products act similarly to the insect growth regulator baits such as Logic® or Award® .
(Bart Drees, Texas Agricultural Extension Service, 409/845-5895, b-drees@tamu.edu)

Electrocuting ants. Texas Tech scientists have developed a patent-pending low voltage, static electrical device that acts as a decoy or "ant trap" when placed in electrical utility housings, such as pad-mounted electric transformers. Ants are shocked by the unit and attract more ants to the device, thereby preventing ants from damaging sensitive electrical components. Field trials are now being conducted in Ft. Worth, Waco, Tyler, Houston, and Arlington.
(Harlan Thorvilson, Texas Tech University, 806/742-2828, rthgt@ttacs.ttu.edu)

A bait station for imported fire ants only. Currently, both imported fire ants and native ants collect bait insecticides. Since maintaining native ant species may be necessary to combat the imported kind, Texas A&M researchers are developing a bait station that keeps out native ants. Since native fire ants have larger head widths and body lengths, the device has entrances large enough only for the imported ants.
(Brad Vinson, Texas Agricultural Experiment Station, 409/845-9754, b-vinson@tamu.edu)

Highlights

  • As a result of Extension applied research, two new fire ant baits registered for agricultural lands will be available in early 1999.
  • A Texas Tech-developed static electrical device that decoys ants away from sensitive electrical components is being tested in five cities.
  • Four county Extension agents were hired to educate homeowners in Texas' biggest cities about managing fire ants by working with their neighbors to coordinate management.
  • The Extension Service conducted a statewide campaign during Fire Ant Awareness Week in September that taught Texans to "Tackle fire ants in the fall for fewer ants in the spring."

Education/Community-Wide Management Program

The Texas Agricultural Extension Service is actively involved in educating Texans about the best currently available methods for managing imported fire ants. Current programs being emphasized include community-wide management programs, where neighborhoods are encouraged to treat for fire ants at the same time, and to start bait-based management programs, like the Two-Step Method, in late summer/early fall.

Educating urban homeowners. The Extension Service has hired four agents to specifically address the red imported fire ant problem in Dallas, Houston, Austin, and San Antonio, where more than 50 percent of the state's population resides. These agents invite homeowner associations to participate in community-wide management programs and answer the public's fire ant questions by phone, the media, demonstrations, and meetings. In 1998, these agents made more than 7,400 contacts.
(Charles Barr, Texas Agricultural Extension Service, 409/845-6800, c-barr@tamu.edu)

Being neighborly. The biggest complaint heard from people trying to control fire ants is, "If my neighbors aren't also controlling them, I'm just wasting my time." The major project for these four urban fire ant agents is to implement and monitor one pilot neighborhood fire ant management program in their city. These neighborhoods are currently being selected. In the meantime, the agents are encouraging homeowner associations to implement community-wide management programs on their own. One neighborhood in College Station has organized their own management program for the past three years. Residents report that they don't have a fire ant problem. In the summer of 1998, both Houston and San Antonio had homeowner groups that organized their own fire ant management program and reported great participation.
(Charles Barr, Texas Agricultural Extension Service, 409/845-6800, c-barr@tamu.edu)

Developing and distributing educational materials. More than 15 fact sheets on various imported fire ant management topics have been developed, printed for release, and posted to a web site (http://fireant.tamu.edu). The web site also includes information about current research. Educational displays, brochures, videos, and other tools are being developed and distributed in quarantined counties.
(Bart Drees, Texas Agricultural Extension Service, 409/845-5895, b-drees@tamu.edu)

Fire Ant Awareness Week Proclaimed by Governor. The week of Sept. 14-20, 1998 was designated Fire Ant Awareness Week to inform the public about managing fire ants and research progress. The educational focus was on "teaming up with your neighbors to tackle fire ants in the fall for fewer ants in the spring." The successful campaign involved billboards, a web site, TV and radio spots, and newspaper and broadcast news coverage. The week was launched with a news conference that unveiled the campaign and highlighted research progress. This effort was one of the Extension Service's first ever coordinated statewide educational campaigns geared toward urban audiences. As a result, accesses to the fire ant web site went from 5,500 average monthly hits to nearly 103,600 in September; county offices fielded countless phone calls; and stores sold out of fire ant bait.
(Bart Drees, Texas Agricultural Extension Service, 409/845-5895, b-drees@tamu.edu)

Highlights

  • Texas Tech and University of Texas surveys found one new county (Callahan County) to be infested with imported fire ants.
  • The Texas Department of Agriculture did not add any new counties to the quarantine list. Inspectors are monitoring and spot-treating for fire ants found in three locations in El Paso. The department has also enhanced its quarantine public awareness program.
  • Texas A&M researchers have developed a geo-graphic information system that will include data from imported and native fire ant surveys. This data then can be interlaced with exist-ing climatic, geo-graphical, and wildlife information to help people make better decisions about which fire ant management methods to use.

    • Survey, Quarantine and Regulatory

    Monitoring the spread of imported fire ants. Texas Department of Agriculture inspectors, along with researchers from Texas A&M, Texas Tech, and the University of Texas, have conducted imported fire ant surveys in counties that border counties quarantined for imported fire ants. No new counties were added to the quarantine list this past year. However, imported fire ants found in Callahan County and at three locations in El Paso are being spot-treated and monitored closely. The USDA imported fire ant quarantine program assures compliance by conducting road station inspections of commercial vehicles and compliance inspections. Currently, there are 244 establishments under this compliance agreement. A public awareness program about quarantine regulations is being enhanced and implemented.
    (John Sneed, Texas Department of Agriculture, 512/457-1625, jsneed@agr.state.tx.us)

    Using computers to track fire ants. Texas A&M researchers have developed a geographic information system that will include results of surveys for quarantine, abundance, and location of imported and native fire ants, agricultural and community-wide management programs, and released biological control agents. These data then can be interlaced with existing climatic, geographical, and wildlife information to better understand the conditions necessary for imported fire ants to exist, the affect they may have on nature, and the success of current and new management programs in reducing fire ant populations. This system can also aid in preventing fire ant invasions by identifying areas that may be prime targets for the pest to infest and then taking preventive measures. (Robert Coulson, Texas Agricultural Experiment Station, 409/845-9725, coulson@tamu.edu)

    Everything you need to know about fire ants. Scientists at Texas A&M are creating an extensive database that will help researchers use computers to simulate ant development and analyze control strategies. (L.T. Wilson, Texas Agricultural Experiment Station, 409/845-4355, wilson@kelsun2.tamu.edu)

    Evaluating the Impact of Fire Ants

    Determining economic damages. Researchers from Texas Tech and Texas A&M are engaging in studies to estimate the economic impact of imported fire ants on various sectors. In one study, they found that the Texas cattle industry sees a $254.9 million loss because of fire ants. This figure is also broken down by county. Scientists also have developed surveys for addressing the ant's impacts on electrical and communication equipment and for assessing wildlife damage. Results from these studies should be seen in 1999. (Eduardo Segarra, Texas Tech University, 806/746-6101, zgseg@ttacs.ttu.edu)

    Impacts on quail and fawns. Texas Tech researchers are determining whether quail and fawns are at risk when imported fire ants are present. They are monitoring more than 68 captured northern bobwhite hens and their nests for their behavior with fire ants present. Also, these scientists have captured and placed 25 pregnant white-tailed deer does in an approved deer facility to study the fawns' responses to fire ants.
    (C. Brad Dabbert, Texas Tech University, 806/742-1983, c7dcb@ttacs.ttu.edu)

    Impacts on livestock. Scientists at Texas Tech are investigating which livestock feeds attract fire ants the most and how various livestock breeds react to fire ant stings. They are also looking into the resulting factors of different livestock breeds grazing on fire ant-infested pastures. This study will help livestock producers to consider fire ant infestation when estimating animal performance and managing their land.
    (A.D. Herring, Texas Tech University, 806/742-1475, anadh@ttacs.ttu.edu)