Peter Kareiva is Lead Scientist for The Nature Conservancy. His current focus is on the examination of different conservation strategies, although he also maintains a program of field research on the invasion of North America by exotic ladybird beetles. Kareiva is also affiliated with the Bren School of the University of California, Santa Barbara and the Environmental Studies Institute at Santa Clara University. Address: The Nature Conservancy, 217 Pine Street, Suite 1100, Seattle, WA 98101. Internet: pkareiva@tnc.org