The larvae themselves continue feeding and excavate further across the inner bark until they reach adulthood and leave to find a new host to start the process anew.
The only direct defense trees have against bark beetles is the resin released when sapwood is breached, which can fill in the tunnels they dig and encase the insects entirely.
[9] In response to the unprecedented spread of bark beetles in the Rocky Mountains and other parts of the western United States, the U.S. Forest Service formed the Western Bark Beetle Research Group (WBBRG) in 2007—a collaboration between scientists from three research stations that pools knowledge and resources to better understand the threat and eventually develop a strategy to combat it.
Self-described as “a modest strategy that reflects current budget realities”, it concedes that not all affected and at-risk forest lands can be covered with the resources at the project's disposal.
Though the strategy does implement some direct prevention techniques, they are rarely used and are primarily for protecting high value trees and maintaining the aesthetic appeal of important tourism sites.
Professor Diana Six at the University of Montana, whose work on forest entomology and pathology has received national attention,[12] has been studying tree species that survive bark beetle outbreaks and her recent findings suggest that survivorship is genetically based and can be inherited.
Instead, she proposes that the long-term sustainability of our forests relies on their adaptation to threats like bark beetles and drought, and that identifying the genetic markings that allow certain tree species to survive the current infestation may yield crucial information that can inform the development of future management approaches that support forest adaptation.