Alien Beetles Tracked with "Ray Guns," Dental Floss

October 16, 2006

Scientists are combining space-age ray guns with dental floss to get a read on how wood-boring beetles such as the Asian longhorned beetle invade new countries.

"These pests have become a problem in the last 20 years or so because of all the foreign trade," said David Williams, an entomologist with the U.S. Department of Agriculture's Animal and Plant Health Inspection Service in Cape Cod, Massachusetts.

The insects hitch rides across oceans in wooden crates and other solid wood materials used in shipping, he explains. Once the containers are unpacked, the insects fly off, mate, and spread.

The Asian longhorned beetle that invaded New York in 1996 has since killed thousands of the state's hardwood trees, including maples, elms, willows, and poplars.

Williams' primary responsibility is to study how to eradicate or at least control invasive insects such as the Asian beetle. (Related photos: "Attack of the Alien Invaders" in National Geographic magazine.)

Typically when an invader arrives, researchers identify its location and search a wider circle around it for other bugs, he says.

"In the case of wood-boring beetles, we'll cut down all the host trees that seem to be infested in an attempt to eradicate it," he said.

"What we need to know is how big the radius of the circle needs to be—how far these bugs can fly."

Harmonic Radar

Harmonic radar is one trick entomologists are using to understand the range of large insects such as the Asian longhorn.

The technique involves a transceiver, which Williams says looks like a ray gun the fictional space hero Buck Rogers might use, along with tiny wire tags attached to the beetles. (Related: "Dragonfly Migration Tracked With Tiny Radio Tags" [October 12, 2005].)

The transceiver sends out a radar beam into the environment that reflects off whatever it hits. Sensors then measure those reflections.

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