Code and data for "What is a specialist? Quantifying host breadth enables impact prediction for invasive herbivores."

These data were compiled in support of the "Predicting the next high-impact insect invasion: Elucidating traits and factors determining the risk of introduced herbivorous insects on North American native plants" project supported by the U.S. Geological Survey John Wesley Powell Center for Analysis and Synthesis, as well as the "Forecasting high-impact insect invasions by integrating probability models with i-Tree from urban to continental scales" project supported by the USDA Forest Service National Urban and Community Forestry Advisory Council. The project working group compiled data for non-native, tree-feeding insects in North America. Data were synthesized from existing resources for a variety of insect traits, traits of their North American host plants, and divergence time between the North American host species and the host species in the insects' native range. These data support analysis performed by the working group on quantifying host breadth and determining the drivers of non-native insect impact on North American tree species.