Range expansion of a domestic bark beetle associated with tree mortality

Mountain pine beetle and emerald ash borer are two examples of high-profile tree-killing insects that have expanded their ranges over the past two decades. Less damaging insects undergoing range expansions are easy to miss but could become problematic if new hosts are encountered or they enter ranges devoid of key natural enemies. Ips grandicollis is native to eastern North America, but appears to have established westward populations in recent years. In this presentation, I share lines of evidence documenting westward spread within North America, including recent detections in Utah and Idaho. This insect has been known to kill pine trees with which is does not share coevolutionary history in areas of the globe such as Australia where it was accidentally introduced in the early 1940s. The insect’s future impacts and behavior in western North America are not yet well understood.