To defeat flies, insect researchers have discovered a breakthrough weapon: a shade of blue.
A team led by University of Florida entomologist Philip Koehler probed flies' eyes to arrive at the conclusion that the household pests can be lured by color – and one color in particular – to be killed.
"It the first true innovation for fly control," Koehler said. "We found out that they really like blue the best."
Scientists stuck a sensor in the bugs' eyes, subjected them to various colors, and then recorded the electrical impulses in the flies' large, ugly peppers. Going in, Dr. Koehler wondered whether yellow would be the bugs' preference, since venerable flypaper and flytraps are often yellow.
But blue won -- in the flies' eyes.
"That's their color," Koehler said. "It's amazing that no one ever looked at it."
UF's entomology lab sits off the bustling main campus, away from the crowded lecture halls and cramped residence halls, in a comparatively sleepy neck of the woods. And yet, this unusual laboratory is teeming.
"There are millions of insects in our building," Dr. Koehler said. "Everything everyone wants to get rid of we bring in here to study."
After pointing out massive roach motels, huge ant colonies, cabinets of crickets, and Petri dishes full of bed bugs, Koehler gave the new fly trap a dry run.
Koehler first sported a buzzing screen box filled with 3,000 flies. As it eerily hummed from the flies' fast beating wings, an assistant removed about 300 of them. Next, he set them free in a large cage containing the star of the show: a pale blue trap.
"It's actually a pretty fast process," Koehler said.
Within a few minutes the insects were dropping (wait for it—wait for it) like flies. They flocked to the irresistible blue box, gobbled up a little poison, and then fell to the floor. As their nervous systems shut down, the flies spun in circles.
"We call that the fly twist," Koehler said. "It's a death dance."
In addition to possessing a pleasing shade of blue, each new trap contains a handful of narrow black lines. Koehler said those dark strips fool flies into thinking they have found a hiding place, such as a crack in a wall or a split in tree bark. And that's where the nerve poison is.
Dr. Koehler estimates each trap can kill at least 40,000 flies before its potency begins to wane. He sees the new design being most helpful in disaster areas and war zones, where fly outbreaks are common.
The baby blue fly trap is now protected by a UF patent. A Sarasota company has licensed the design under the name "Florida Fly Baiter," which is sold online. Expect to pay about $12 per trap.