BEETLES IN THE WOODS

“This immense number of species allegedly led evolutionary biologist J. B. S. Haldane to quip when some theologians asked him what could be inferred about the mind of the Creator from the works of His Creation that God displayed "An inordinate fondness for beetles.’”

Beetles are the insects with the largest number of known species. They are classified in the order Coleoptera, "sheathed wing", which contains more described species than in any other order in the animal kingdom, constituting about 25% of all known life-forms, and 40% of all described insect species. The latest afflictor of the human fondness for the world as we know it now is the pine bark beetle. It doesn’t eat us, but rather the phloem (the green layer just under the hard bark that carries sap through the tree) of conifers. As it goes, it plugs up the phloem until the tree loses its circulation and dies.

One excellent paper calls it a “Darth Vader,” and if a thing only a quarter-of-an-inch long can convey the black platedness of Darth, this description is apt. Aside from spotting one in “person” so to speak, one looks at one’s tree for “pitch-tubes,” because pitch welling up and forcing the beetle out is the main defense of the tree. (It is NOT an inanimate object, a piece of furniture.) Sometimes that works and there are substances one can soak into the ground under the tree that will help it do that. “It isn't the number of pitch-out tubes that kill the pine tree but the beetles carry blue stain fungi which, if established, will block the tree resin response. Over time (usually within 2 weeks of attack), the trees are overwhelmed.” Fungi sometimes seem like the ultimate weapon, because they are so basic and everywhere.

Infestations of beetles, like everything else except maybe mineral deposits, are weather-related, so as the weather swings back and forth through its variations, the beetles respond. Extreme cold can kill them. Warm is good for them. When they kill a lot of trees, turning them the orange of tree death, the trees stop converting carbon dioxide into oxygen (all that lovely Rocky Mountain air) which is one way of diminishing green house gases. The trees can be cut down but the wood will have to be sanitized. Some success comes from putting clear plastic sheeting over the wood so that the resulting accumulating solar heat cooks the beetles and their larva. It takes weeks. Burning is effective, and probably in the past natural mosaic burns resulting from lightning strikes has been a control agent. Today, more than yesterday, we cannot burn because so many people have moved out to the forest to commune with the trees and do not like to push boughs back from their eaves. The richer and more elaborate the refuge, the more reluctant to fireproof the investment.

The prairies have provided conifers in farm shelterbelts that obligingly provide hopscotch loci from one to another possible target -- otherwise the Western cities with their much-loved ornamental blue spruces (loved as much as the elms) would be a little safer. It is the females who pioneer new locations, so one defense is to hang in the tree a little bag saturated in pheromones that say, “This tree taken, you jezebel! Move on! You’re not wanted.” It only works as long as there are enough trees to go around, because scarcity can make the beetles stand and fight.

So mostly our defense is the same one as for the Dutch Elm Disease: cull the diseased trees and burn or otherwise treat (chipping, chemicals) the wood, discourage invaders, and hope for a week of forty-below weather. Right now that strategy is being used to discourage contagious pneumonia among mountain sheep, which can spread to domestic sheep.

But we aren’t licked yet. Bonnie Stevens, a reporter at the Arizona Daily Sun, tells us beetles are all ears. "Insects can have ears almost anywhere, on their wings, legs, antennas or abdomen," Gronenberg said. "It's important to find out all about the sound these beetles use to communicate. Then we can aim that sound and do something to their brains so they don't respond properly."

Like SWAT teams trying to drive holed up killers out of their houses, rock music was the first attempt to annoy the beetles, which says more about researchers than bugs. But the researchers did listen. In a Northern Arizona University School of Forestry lab, researchers are listening to the scratching, scraping, crunching of the Ips bark beetle and its cousins chewing the life out of ponderosa, pinyon and lodgepole pines. They recorded this stuff and played it back to the beetles.

"Our interest is to use acoustic sounds, specific only to each species, that make beetles uncomfortable and not want to be in that environment," said NAU Forest Entomology Professor Richard Hofstetter.

The researchers “started creating phloem sandwiches, slices of infested pine trees encased in Plexiglas, to build ant farms of sorts. Using tiny speakers, like the kind in musical greeting cards, they piped sound in and also recorded sounds coming out, sounds the bugs were making.” (Hey, I have a greeting card that tweets like a ground squirrel. It’s a great cat caller!)

"We could use a particular aggression call that would make the beetles move away from the sound as if they were avoiding another beetle. Or we could make our beetle sounds louder and stronger than that of a male beetle calling to a female, which would make the female beetle reject the male and go toward our speaker," Hofstetter said. "We found we could disrupt mating, tunneling and reproduction. We could even make the beetles turn on each other, which normally they would not do."

The reporter says, “Wearing a headset, McGuire would listen and watch the beetles on a computer monitor hooked up to a microscope.” One can’t really resist the mental image of a village of beetles bopping up and down the tunnels with the latest jelly earbuds attached to iBugs.

"We observed and recorded beetles mating two or three times," McGuire said. "Then we'd play the beetle sounds that we manipulated and watch in horror as the male beetle would tear the female apart. This is not normal behavior in the natural world." Hmmm. He doesn’t live where I do.

"If we know how they hear and what they hear, we can disrupt that behavior," said NAU forest science doctorate student Kasey Yturralde. "If we can do that, we may be able to stop this mass aggregation and the killing of trees. But right now, we don't even know where the beetles' ears are."