She became a member of the Dartmouth faculty in 2004 and currently mentors four graduate students. Her research explores the interactions between multiple species in biological communities. The Irwin lab is especially interested in studying the relationship between pollinators and their flower hosts, and the invasion of new environments by non-native species. Irwin and her students examine how factors including environmental change and plant interactions with species that harm them, such as herbivores, influence pollination services.