When an invasive insect appears, responders must quickly set monitoring traps in the area to determine the extent of the pest outbreak. For an outbreak of Mediterranean fruit flies (Ceratitis capitata), for instance, traps such as this McPhail trap might be used. Researchers at the U.S. Department of Agriculture are working to improve the design of grids for trap placement in such efforts, known as delimitation surveys, and they aim to publish new guidelines after field experiments are completed later this year. (Photo by Peggy Greb, USDA Agricultural Research Service, Bugwood.org)