Skip to main content
U.S. flag

An official website of the United States government

Evolutionary history predicts high-impact invasions by herbivorous insects

October 17, 2019

A long‐standing goal of invasion biology is to identify factors driving highly variable impacts of non‐native species. Although hypotheses exist that emphasize the role of evolutionary history (e.g., enemy release hypothesis & defense‐free space hypothesis), predicting the impact of non‐native herbivorous insects has eluded scientists for over a century.
Using a census of all 58 non‐native conifer‐specialist insects in North America, we quantified the contribution of over 25 factors that could affect the impact they have on their novel hosts, including insect traits (fecundity, voltinism, native range, etc.), host traits (shade tolerance, growth rate, wood density, etc.), and evolutionary relationships (between native and novel hosts and insects).
We discovered that divergence times between native and novel hosts, the shade and drought tolerance of the novel host, and the presence of a coevolved congener on a shared host, were more predictive of impact than the traits of the invading insect. These factors built upon each other to strengthen our ability to predict the risk of a non‐native insect becoming invasive. This research is the first to empirically support historically assumed hypotheses about the importance of evolutionary history as a major driver of impact of non‐native herbivorous insects.
Our novel, integrated model predicts whether a non‐native insect not yet present in North America will have a one in 6.5 to a one in 2,858 chance of causing widespread mortality of a conifer species if established (R2 = 0.91)
Synthesis and applications. With this advancement, the risk to other conifer host species and regions can be assessed, and regulatory and pest management efforts can be more efficiently prioritized.

Publication Year 2019
Title Evolutionary history predicts high-impact invasions by herbivorous insects
DOI 10.1002/ece3.5709
Authors Angela M. Mech, Kathryn A. Thomas, Travis D. Marsico, Daniel A. Herms, Craig Allen, Matthew P. Ayres, Kamal J.K. Gandhi, Jessica Gurevitch, Nathan P. Havill, Ruth A. Hufbauer, Andrew M. Liebhold, Kenneth F. Raffa, Ashley N. Schulz, Daniel R. Uden, Patrick C. Tobin
Publication Type Article
Publication Subtype Journal Article
Series Title Ecology and Evolution
Index ID 70206093
Record Source USGS Publications Warehouse
USGS Organization Southwest Biological Science Center; John Wesley Powell Center for Analysis and Synthesis