Analysis of Body Measurements and Wing Shape to Discriminate Rhagoletis pomonella and Rhagoletis zephyria (Diptera: Tephritidae) in Washington State

Rhagoletis pomonella (Walsh) (Diptera: Tephritidae) is a quarantine pest of apple (Malus sp.) inWashington state that is almost identical morphologically to Rhagoletis zephyria Snow, a nonpest of apple. Historically, the longer ovipositor inR. pomonella has been used to separate it from R. zephyria, despite overlap in ovipositor lengths. Here, the objectives were to determinewhether use of multiple bodymeasurements andwing shape can improve discrimination of the species. Ovipositor lengths allowed94.6%correct identiÞcationof femaleR.pomonellabutonly 7.0%correct identiÞcation of R. zephyria. We found that multiple body measurements and wing shape can better separate these species.Canonical variates analysis (CVA)ofninebodymeasurements in femaleßies largely separated the species. In contrast, CVA of nine bodymeasurements poorly separated themales of these species. Discriminant analysis using nine body measurements classiÞed female R. pomonella and R. zephyria with 95.4 and 100%accuracy, respectively.Geometricmorphometrics andCVA separatedwing shapes between species in both sexes. Bookstein shape coordinates indicated that the wing of R. pomonella is more tapered at the tip than that of R. zephyria. Use of wing shape in an assignments test identiÞed femaleR. pomonellawith 98.5% and femaleR. zephyriawith 99.0% accuracy, and it correctly identiÞed 100% of ßies whose identities were questionable based on ovipositor lengths. Results indicate that use of multiple body measurements or wing shape is an improvement over the use of ovipositor length alone for identifying female R. pomonella and R. zephyria in Washington state.