Outsmarting the Destructive Mountain Pine Beetle: Saving the Lodgepole Forests

The mountain pine beetle is nothing to mess with. The destructive insect is killing off lodgepole pine forests and has even extended its reach to jack pine forests. Now, scientists are looking for an effective bait to get ahead of the spread of this beetle, which could help save forests in the future.

"Right now we don't know how efficient currently available commercial baits will be in catching beetles in jack pine forest, as they were developed to catch the beetle in lodgepole pine forests," said Nadir Erbilgin, one of the researchers, in a news release.

In order to better understand what might attract this insect and halt its spread, researchers examined pheromones emitted by the pest. More specifically, the scientists looked at the tree chemical compounds that play critical roles in the beetle's pheromone production and attraction in both their established lodgepole pine host and in the newer jack pine host.

In the end, the researchers found that the beetles emit the same pheromones from both tree species. Yet the female beetles in the jack pine tree emit more trans-verbenol, a pheromone that initiates the beetle aggregation in host trees. Females lead the first attacks on trees while sending out pheromone signals for more beetles to join the aggregation, so it's crucial to take note of female behavior.

"Without this initial chemical signaling, the beetles couldn't aggregate on the same tree," said Erbilgin.

The scientists also found that beetle attacks also induce a release of the volatile tree chemical, 3-carene. They then found during field tests that when 3-carene was added to a mixture mimicking the aggregation pheromone, beetle capture in traps increased.

Understanding these chemicals is crucial for creating attractant that can hopefully curtail the invasion of beetles. This is especially important as trees and entire forests are impacted by these insects. By creating an effective bait, scientists could potentially halt the spread of these destructive beetles, which would be a boon for North American lodgepole pine forests.

The findings are published in the journal New Phytologist.