David L. Wagner is a professor of ecology and evolutionary biology. His core research interests are in the biosystematic of moths, insect decline, and invertebrate conservation. He has published more than 200 scientific papers on moths, butterflies, bees, dragonflies, insect behavior and ecology, and insect systematics. His biosystematic research interests have focused on ghost moths (Hepialidae), several families of leafminers, and Noctuidae. He has authored nine books, four of which are on caterpillars—his 2005 guide with Princeton University Press, Caterpillars of Eastern North America is in its ninth printing. Wagner is currently working on a multi-volume western book on the caterpillars of western North America.