How a group of bugs can increase the threat of wildfires
‘There’s really nothing you can do,’ entomologist says
A female mountain pine beetle chews into a tree to deposit eggs in this undated image.
(USDA/U.S. Forest Service)
A group of bugs is taking advantage of the drought in the western U.S., and their advantageous nature can lead to an increase in the wildfire threat in the parched region.
"Bark beetles are a huge group of insects," said Howard Russell, an entomologist at Michigan State University.
According to Russell, the bark beetle is actually in the same family as weevils, which are insects infamous for the ability to destroy crops and stored grain.
The extremely dry conditions that have plagued the western reaches of the country off-and-on for years have led to ideal conditions for the bugs Russell described as "opportunistic beetles."
The U.S. Drought Monitor as of Sept. 20, 2021.
(NDIS)
"These would be attracted to stressed trees," Russell said. "So, a drought-stressed tree would be far more attractive to certain types of bark beetles than a healthy, vigorously-growing tree."
Once burrowed into the tree, according to Russell, these bugs will use the last bits of life to feed their brood.
"Then in a sense, finish the plant off by their attack of the tree," Russell said.
According to Russell, there’s also a variety of bark beetles that could be considered predatory. Examples of these include the southern pine and mountain pine bark beetles.
"The adults absolutely have to kill the tree that they’re working on in order for their larvae to survive and develop in that tree," Russell said about the southern pine variety.
Russell said the mountain pine bark beetle is equally destructive.
"As temperatures warm, these beetles become more active and are spreading, and they’ve killed, like, thousands of acres of trees in British Columbia, and then they’re working their way down the Rockies and into the U.S.," Russell said.
More dead, dry trees equal more potential fuel for wildfires that could spark. No matter which species of bark beetles, Russell said, their ability to increase the wildfire threat is driven by one thing.
"Really, it comes back to weather," Russell said. "The drought stress is the key element there. The beetles are just responding to the drought-stressed trees."
Combatting the beetles once they enter a tree-filled region isn’t easy. In fact, Russell said, it’s nearly impossible to stop them once they start.
"There’s really nothing you can do about the beetles in forest situations," Russell said.