Tuesday, February 09, 2010

At War in the Forest: Ballad of the Bark Beetle

Bark beetles have killed nearly 80 million ponderosa, piƱon and lodgepole pines in Arizona and New Mexico and tens of millions more across the West over the past decade. Years of punishing drought left the trees unable to protect themselves against the attacks, which carve ugly scars into forests, weaken the surrounding ecosystem and heighten wildfire danger.

Forest managers can apply insecticide to individual trees or small stands, but forestwide treatments are impractical and would be wildly expensive and potentially risky to other plants and wildlife.

Enter Reagan McGuire, a research assistant who wondered what would happen if the beetles were blasted with noise, creating an acoustic stress that might change their behavior. He sold Hofstetter on the idea, and the experiment was hatched at NAU's School of Forestry lab.

They collected tree trunks infested with bark beetles and sandwiched slices of the trees between clear plastic plates, creating what looked like the old ant farms once sold in the back pages of magazines.

Working in the lab, McGuire piped in the music through tiny speakers, the sort you might find in a singing greeting card. He watched the reaction of the beetles using a microscope. The rock music didn't seem to annoy the bugs, nor did Rush [Limbaugh] in reverse.

McGuire and Hofstetter decided to try something different. They recorded the sounds of the beetles and played them back, manipulating them to test the response.

Suddenly, every little thing they did seemed to provoke the beetles.

"We could use a particular aggression call that would make the beetles move away from the sound as if they were avoiding another beetle," Hofstetter said.

When they made the beetle sounds louder and stronger than a typical male mating call, he said, the female beetle rejected the male and moved toward the electronic sound.

Even more surprising was what the beetles did to each other. The researchers manipulated the sounds and, at a certain point, the male stopped mating and tore the female apart, McGuire said.

"This is not normal behavior in the natural world," he said. _AzCentral

Al Fin botanists and entomologists respond to McGuire: No shite Shirlock! If it were normal behaviour in the natural world, there would be no bark beetles at all by now. It is your job to make it common behaviour in the pine forest. Otherwise, give back all those grants!

Biomass companies had better grab up as many dead pines as they can, while they last. If the bark beetles are driven to distraction by the manipulation of their own sounds, pine forests may have a few years to recover -- until the next deadly pest comes along.

First published at Al Fin, The Next Level


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