Insect Outbreaks Across The Pacific Northwest

PROJECT TEAM

Alex Pane, PhD Student (University of Washington)

Dr. Allan Carroll, PhD

Dr. Patrick Tobin, PhD (University of Washington)

A Dependence on Climatic Conditions

INSECTS ARE STRONGLY AFFECTED by climate and changes in climate because many of their physiological processes are regulated by temperature. Consequently, warming temperatures have critical ramifications to insect populations, including more frequent and/or more intense outbreaks. Recent work has shown that climate change has allowed some species to expand their geographical range and abundance, whereas others have been reported to experience range retraction and decreased abundance. Understanding how climate warming will affect forest insect dynamics remains an important avenue of research with both ecological and economic implications.

“Recent work has shown that climate change has allowed some species to expand their geographical range and abundance, whereas others have been reported to experience range retraction and decreased abundance.”

– Alex Pane

Varied Responses Across Scales

INCREASES IN WINTER TEMPERATURES can reduce insect overwintering mortality, leading to high population densities in the following spring and summer. Warming temperatures could alter trophic interactions, especially when interacting species differentially respond to temperature. Using historical aerial detection survey data (1960-2019) from Oregon, Washington, and British Columbia, this project will quantify how the spatial and temporal dynamics of bark beetles, defoliators, and their interactions at local and regional scales have changed through time. We will also assess how natural enemy communities influence the dynamics of two native forest insect species, Douglas-fir beetle and western spruce budworm, both of which have a propensity for outbreaks east of the Cascade Mountain Range, but not west.