Texas A&M Doctoral Student Builds Better Fly Trap

COLLEGE STATION -– Thomas Edison said success is 10 percent inspiration and 90 percent perspiration. But Robert Puckett showed he could build a better fly trap – phorid fly trap, that is – with 90 percent inspiration.

Robert Puckett, a doctoral candidate in the department of entomology at Texas A&M University, puts out a phorid fly trap. He invented the trap to help determine whether released phorid flies, used to control fire ants, are reproducing and spreading out. (Texas Agricultural Experiment Station photo by Edith Chenault)

The doctoral candidate in the department of entomology at Texas A&M University took a pizza tent and applied what he knew about the biology of the phorid fly to make a successful trap. Pizza tents—also called pizza tri-stands—are the gadgets in take-out pizza boxes that keep the top from caving in.

Puckett, also a Texas Cooperative Extension assistant in the department of entomology, knew from his studies the phorid fly likes to perch on a blade of grass or whatever is handy when it is waiting for a fire ant that it can parasitize. The female phorid fly will attack the ant, laying its eggs in the body. The larvae burrow their way up to the fire ant’s head, growing and releasing enzymes that decapitate the ant.

Puckett’s trap uses fire ant midden, which is essentially the fire ants’ trash heap, to attract phorid flies. The decomposing dead fire ants release a plume of chemicals called kairomones, which attract phorid flies.

“The ant bone yards seem to be an integral part of the biology and host-finding behavior of the phorid flies,” Puckett said.

But looking for phorid flies is worse than looking for a needle in a haystack. They are tiny, smaller than the head of a straight pin.

A phorid fly trap invented by Robert Puckett, a doctoral candidate in the department of entomology at Texas A&M University. Puckett utilized a pizza tent, or pizza tripod, to make the trap. Phorid flies, the tiny black specks, are trapped on the prongs by a sticky substance. (Texas Agricultural Experiment Station photo by Edith Chenault)

Puckett tried traditional traps, but the insects are so minute they could fly in and out without getting trapped on the sticky walls.

He began trying to think of ways he could take advantage of the insects’ perching habits. Puckett felt something with multiple prongs and a solid base and coated with a sticky substance would do the trick.

Then, “We were sitting around eating pizza,” and the idea struck him.

The pizza tent, turned upside down, had multiple prongs and a solid base. He coated the prongs with Tanglefoot insect trap coating, something like the coating for flypaper.

The trap is placed in a dish that contains midden. That “kairomone gumbo” of the decaying fire ants attracts flies, he said. The flies perch on the trap “to study the situation” and are caught, he added.

The trap is more efficient in terms of time and personnel than the standard methods, Puckett said. Instead of counting flies for a couple of hours around a disturbed fire ant mound, he can place the new trap out every mile using global positioning system technology. He then will go back to collect them 24 hours later.

Phorid flies caught on a trap invented by Robert Puckett, a doctoral student in the department of entomology at Texas A&M University. Phorid flies, which are used to control fire ants, are smaller than the head of a straight pin, making them difficult to see and trap. (Texas Agricultural Experiment Station photo by Edith Chenault)

The passive trap also successfully collected flies during all of the tests in the field, he added. Other methods varied from 10 percent to 60 percent success.

The trap is inexpensive. Puckett and his committee chair, Dr. Marvin Harris, professor of entomology with the Texas Agricultural Experiment Station, are considering distributing them to grade schools and scouting groups so they can learn more about phorid flies. At some point, they also may distribute these to Extension agents and Master Gardeners to help in the observation of distribution areas, Puckett said.

Tracking phorid flies is important because the U.S. Department of Agriculture and researchers at University of Texas, Texas A&M and elsewhere are releasing phorids to test as part of the arsenal against red imported fire ants. The phorid flies are native to South America and appear to be important in regulating fire ant densities in their native range.

“The initial inoculative release of the flies costs about $10,000 dollars per site, and, if successful, the flies will reproduce and expand on their own to attack fire ants over hundreds of square miles,” Puckett said. “Releases are not always successful, and we want to know what factors are affecting outcomes.”

Puckett is studying those factors—phorid fly habitat, potential expansion corridors, and parasite-host interactions—as part of his doctoral research.

Other researchers in Texas and Florida have taken his idea and adapted it to their research, he added.

Dr. Sanford Porter with the USDA Agricultural Research Service in Gainesville, Fla., and Dr. Larry Gilbert with the University of Texas collaborated with Puckett on this project. Puckett’s work is funded by the USDA Agricultural Research Service.


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