Evolutionary ecologist Glen Ray Hood, Ph.D., and his students at Wayne State University in Detroit are investigating which insect-induced plant galls are best able to accumulate contaminants. They are especially interested in galls on common plants, such as goldenrod. Eurosta solidaginis, sometimes known as the goldenrod gall fly, causes spherical galls on goldenrod stems, such as the one shown here. (Photo by Leslie Mertz, Ph.D.)