Her research focuses on the ecology and evolution of multiple-species interactions, pollination biology and species invasions. Specific interests include the relative importance of direct and indirect effects of antagonists on the ecology and evolution of plant-pollinator mutualisms, and whether plant interactions with mutualists and antagonists simultaneously shape and constrain selection on nectar traits. Irwin’s current research projects include how pollinators and pollination are responding to environmental change (invasive species, urbanization, and climate change), exploitation of pollination mutualisms, and effects of secondary compounds on pollinators and their parasites.