I study the ecology and evolution of spittlebugs, insects of the superfamily Cercopoidea (Hemiptera: Auchenorrhyncha). My research and fieldwork have centered on spittlebug host plant relationships (including the important roles of microbial symbionts), spittlebug polymorphism (multiple color forms), and spittlebug warning coloration (striking color patterns that deflect predators). In recent years, I have documented a marked association between spittlebugs and ectomycorrhizal host plants, likely a consequence of xylem feeding. I also spurred a study demonstrating that the meadow spittlebug, Philaenus spumarius, has more documented host plants than any other insect. Presently, I have completed a book on the biology and agricultural importance of spittlebugs for Cornell University Press, to be published May 2026. This will be the first book of its kind. With American Museum of Natural History colleagues, I am investigating a vineyard spittlebug suspected of spreading the bacterial disease Xylella fastidiosa in California. In addition, I am working with colleagues at other institutions to describe and document spittlebug diversity in Costa Rica, Mexico, the Philippines and Vietnam. In conjunction with this work, I continue to describe spittlebug diversity in the United States. I welcome correspondence from anyone interested in spittlebug biology.