You might expect to find a blog post about how to use pheromones to their full potential on a dating blog, but we’re not talking about human pheromones. We’re talking about beetles.

A close-up of a mountain pine beetle.
A close-up of a mountain pine beetle. Credit: Ward Strong, B.C. Ministry of Forests, Lands, and Natural Resource Operations / Simon Fraser University Public Affairs and Media Relations

At American Forests, we’ve been using a synthetic version of the pheromone verbenone to repel the destructive mountain pine beetle from whitebark pine. The verbenone patches mimic that which the beetles give off to communicate to other beetles that the tree is full. “No room — find your own tree,” the pheromones say. By arming healthy trees that are most likely to survive other threats with verbenone patches, we can help give the whitebark pine population a fighting chance against the mountain pine beetle.

But there’s another way that pheromones can be used to help forests under siege by these beetles. They don’t just repel — they also attract. Researchers from the University of Alberta are developing a bait to monitor the beetles’ activity in Canadian jack pine forests. By using pheromones to attract the beetles to “trap trees,” the beetle population can be concentrated to a limited number of trees. Then, those trees — and the beetles along with them — can be removed, sparing the surrounding trees from attack.

Studying the concentration of beetles on trap trees can also tell us more about their population in different areas. This could help managers make decisions about priority areas for containing what lead researcher Dr. Nadir Erbilgin calls “the most damaging insect in North America.”

Though baits of this kind have been used in lodgepole pine forests before, this study is investigating their use with jack pine — a tree that, until recently, was not believed to support the mountain pine beetle. But, as the beetle population explodes across the Western U.S., they’re increasingly attacking jack pine — and whitebark pine. Whitebark pine lives at elevations in which the beetles previously ventured rarely and died during winter. As winters warm up, the beetles are getting more and more comfortable — and living longer — at higher elevations. Their attack on the whitebark pine population is having cascading effects throughout ecosystems like the Greater Yellowstone Area.

The study on jack pine bait was published last month in New Phytologist and the researchers’ field trials in the jack pine forests will continue through the summer. In the meantime, you can help us with our work repelling the beetles from healthy whitebark pine trees by supporting our Endangered Western Forests initiative. Let’s arm our forests with the tools to fight off North America’s “most damaging insect.”