Off With Their Heads


Fire ants at Lake Waco Wetlands decapitated by newly released flies

By Pamela Bond

Waco Tribune-Herald

June 15, 2007

Decapitated bodies lie scattered on the ground, victims of an unforeseen and lightning-fast attack that happened not in a horror film, but at the Lake Waco Wetlands.

And the victims were fire ants.

Phorid flies, which kill South American red fire ants by decapitation, were released into the wetlands Thursday by Robert Puckett, a Texas extension assistant and doctoral student at Texas A&M University.

The phorid fly is the ant’s natural predator in South America, where it is commonly called the decapitating fly, Puckett said. It kills fire ants by laying an egg in the head of the ant.

The ant’s head then falls off, killing the ant. A female fly carries 100 to 200 eggs and lays each in a different ant. These imported fire ants are not native to Texas and have disrupted the natural ecosystem, Puckett said.

Although it is unclear how they got here, the ants came to the United States in the 1930s, and now there are more of them per acre in the United States than in South America, with no natural predators here to keep the population in check.

“The whole idea is to balance things out and tip the scales back to the natural species,” Puckett said. “There are two original species of fire ants in Texas, and both were pushed out by this fire ant.”

Fire ants are also economic pests, Puckett said. Agriculturally, fire ants can cause loss of livestock and crops. In an urban setting, fire ants present problems to dwellings and electrical wires.

“One ant gets electrocuted, gives off pheromones, and other ants follow,” Puckett said. “Pretty soon, all these ants have blown a circuit. I had some blow out a circuit in my house — that’s their revenge on me.”

South American fire ants sting people, and individuals can develop allergic reactions. Young livestock, groundnesting birds (like quail) and lizards such as the Texas horned lizard also are affected by these ants.

Researchers started studying the use of phorid flies about eight years ago while looking to the ant’s natural predators to suppress populations instead of the conventional use of chemical insecticides, which can be expensive and harmful to the environment. In addition to suppressing ant populations, the flies’ presence shuts down the foraging instincts of the ants.

Field studies have had successful results, Puckett said. A pheromone given off by ants when their colony is disturbed attracts the flies. Puckett releases about 40 flies on each mound and continues to agitate the mound every 10 to 15 minutes for about 90 minutes. In the heat of summer, the ants are often slow, so Puckett uses the electrical currents of a modified cattle prod to stimulate them.

The flies Puckett uses are from a U.S. Department of Agriculture rearing facility in Gainesville, Fla. They are kept in plastic containers until Puckett is ready to gather them for a release. Because they only can develop inside the head of this specific ant, the phorid flies do not target native fire ants or other bugs. Adult flies eat nectar, but since they need so little to survive, Puckett said, they will not compete with bees.

Since the flies are small, only the size of an ant’s head at maturity, and they do not bite, Puckett said they should not be a problem for people.

“I’ve been working in Caldwell and doing this for three years, and I’ve never seen one except out in the field,” Puckett said. “They won’t be a nuisance in terms of bothering people.”

Thursday was the first phorid fly release in Waco. Puckett said he chose the wetlands because it was protected, “has a nice corridor for expansion and a high density of ant mounds.”

“I think it’s a neat deal,” said Nora Schell, program coordinator for the Lake Waco Wetlands Center. “This place is a wildlife habitat, and we’re also out here for education. If we can help, then we will. And who knows? This may be the up-and-coming suppression technique for ants.”

Puckett also chose the location because it was equidistant from release sites in College Station, Caldwell and the Dallas/Fort Worth area.

“The goal is to use select release sites that are far enough apart to let the flies do their work and spread out,” Puckett said.

The flies also have been released in Vidor, Brazoria County, Austin, Huntsville, Paris, Beeville and Livingston.

“It’s really interesting,” said John Fell, an undergraduate entomology student at Texas A&M who works with Puckett. “When we go back to determine how many flies are in the area, there’s usually 30 to 40 of them on each trap, so I’d say it’s working.”




Vegetables Power Buses

By Pamela bond

North Texas Daily

Feb. 7, 2006

Vegetables, instead of gasoline, may soon fuel NT’s etrans bus system. The Denton County Transportation Authority (DCTA), which runs etrans, will start experimenting with biodiesel fuel in their buses sometime this spring.

Biodiesel, an alternate fuel source to petroleum recognized by the EPA, is a nontoxic fuel made from vegetable oil. It greatly reduces emissions which contribute to air pollution. In fact, if used on a life cycle basis, biodiesel has the potential to reduce carbon dioxide by 78 percent compared to petroleum diesel, according to EPA reports.

Biodiesel is becoming a common alternative to fossil fuels, due to its lower cost and environmentally safer emissions. The biodiesel plant of Denton, the first public/private plant of its kind in the US, currently supplies fuel to the City of Denton’s trucks and school buses, and will be used in DCTA’s experiment.

“The city partnered with Biodiesel Industries a year ago last winter,” said Gene Holloway, director of transportation and planning for Denton Independent School District (DISD). “They put in place a processing plant on the landfill, and in an April-May time period, biodiesel was fueling the city’s trucks.”

The biodiesel plant is owned by the Biodiesel Industries of Greater Dallas/ Fort Worth. Located on the same site as Denton’s landfill, it uses biogases produced naturally by the landfill, such as methane, to power all heat and electricity in the plant. This innovation is the first of its kind, and Denton’s biodiesel plant received national news coverage because of it.

The type of fuel produced by this plant is called B20, meaning it’s a blend of 80 percent petroleum and 20 percent biodiesel. By using this fuel in their trucks, the City of Denton will reduce air-polluting emissions by up to 12 tons per year, according to the city’s biodiesel facility webpage,

In February 2005, the Clean Air Task Force released the results to its nation-wide study, which ranked Dallas as the 14th worst city for diesel emissions and theorized that diesel pollution is responsible for 879 deaths in Texas each year.

DCTA’s board of directors became interested in the fuel source after becoming aware of its environmental and cost-cutting benefits.

“It is an option but we haven’t made a final choice on whether or not to implement it,” said Scott Neeley, director of program development for DTCA. “We’ll start running one or two regular service buses on biodiesel and see how they run, whether they get better gas mileage or if it will require extra service or maintenance.”

DCTA hopes to start the experiment, using ultra low sulfur biodiesel, by March. If the operating results prove promising and the fuel does not conflict with the bus’s warranty, DCTA will start using biodiesel in more test buses.

“It [biodiesel] seems to be working pretty well in the city’s trucks, from what I can tell,” said Joe Richmond, associate director of NT’s transportation services. “I haven’t heard anything bad about it. But we’ll have to see what the DCTA has to say about it.”

DISD has already experimented with biodiesel fuel and will start using it in school buses this month.

“From last fall to the present we investigated implementing biodiesel as a cost-cutting and an environmental measure,” Holloway said. “We were very satisfied with the results, and the fuel satisfied the requirements of the warranty. We’re looking forward to implementing it into our fleet.”

Of DISD’s 144 buses, 36 will run on biodiesel and another 70 will run on propane. The rest will run on unleaded gasoline.

“We’re practicing what we teach about environmental concerns,” Holloway said. “From 1995 to 1996, we initiated and embrace alternate fuels by switching over half out fleet to propane.”

If DCTA’s experiment yields the same results as DISD’s did, more of Denton’s buses, including etrans, could start running on biodiesel fuel.

“We’ll start out with a demonstration, running one or two buses under different operating conditions,” Neeley said. “It could prove to be both cheaper and environmentally safer. We won’t know until results start coming in if there are other benefits.”

Landfill Turns into Green Energy Source

By Pamela Bond

North Texas Daily

Aug. 31, 2005

Each person creates 4.4 pounds of trash a day, on average. Multiply that by the 300 million people living in America, and that’s a lot of garbage. It’s no wonder landfill space is problem – a problem that Denton hopes to avoid.

The City of Denton plans to implement a new method in its landfill within the next two years– one that uses a liquid to help it decompose faster than the traditional “dry” landfills.

The new landfill will utilize a bioreactor method. Bioreactors break down solid wastes using organic substances, Dr. Sam Atkinson, of the biology department, said.

More specifically, Denton’s landfill will use an anabolic bioreactor, meaning liquid will serve as the catalyst.

“In the landfill, there are a lot of microorganisms present in the waste, and we simply add water and nutrients to allow them to grow faster and therefore consume more,” Vance Kemler, Denton solid waste director, said.

The liquid is called leachate. In anabolic bioreactor landfills leachate is recycled throughout the waste, speeding the process by which microorganisms decompose it. Methane gas emissions are produced as a by-product.

While the current landfill produces methane gas, among others, the new landfill will emit much more – a concern for some environmental groups like the Environmental Protection Agency.

“We’re currently using the methane in a boiler, where it’s heated and used for energy,” Kemler said. “With the new landfill, the rest can either be sold here in town for energy use or we can buy a generator and use the methane to produce energy.”

The extra gas for energy uses is one of the landfill’s benefits, Kemler said. Also, the landfill will decompose and stabilize more quickly, making more space available.

However, there is an added cost, in the beginning, to run the landfill.

“The initial capital cost is 10 percent higher, but it is offset by the extra space we’ll have as a result,” Kemler said. “In the end it will be about the same.”

The Environmental Protection Agency is currently studying three test cases on bioreactor landfills, and therefore has not taken a permanent stance on the issue. However, at a bioreactor conference in February 2003, the Agency came to a preliminary conclusion that when gas emissions are safely collected, bioreactor landfills are safe for the environment. They prevent liquids from contaminating groundwater with two layers of lining. Also, minimizing the landfill space prolongs its life, and therefore avoids some of the long-term risks, according to the Agency’s reports.

“It’s a really good way of running a landfill,” Fred Doran, senior environmental engineer and project manager for R. W. Beck in Minneapolis, Min., said. “It stabilizes the waste more quickly. It allows you to take advantage of landfill gases. It reduces environmental risks because the leachate is more stabilized. And from a geological standpoint it’s a much better alternative because there’s less erosion when closing a landfill.”

Currently, there are 70 other bioreactor landfills in the United States. Denton’s Municipal Landfill will be the first of its kind in Texas, once the bioreactor method is completed.