Jackson Audley, Ph.D. (left), and the late Steven Seybold, Ph.D., pose in front of a northern California black walnut tree infested with walnut twig beetles (Pityophthorus juglandis) in downtown Davis, California. Seybold and his lab pioneered much of the early research on the walnut twig beetle and were responsible for the discovery of the male-produced aggregation pheromone. (Photo by Kathy Keatley Garvey)