The aspen forest where our team conducted our recent study. Mark R. Zierden September 19, 2024 Invasive caterpillars can make aspen forests more toxic for native insects – a team of ecologists explains how Richard L. Lindroth, University of Wisconsin-Madison and Patricia C. Fernandez, Universidad de Buenos Aires Research finds that extensive feeding by invasive insects can cause trees to produce defense compounds, to the detriment of valued native insects.