New hosts of western cherry fruit fly, Rhagoletis indifferens (Diptera: Tephritidae), and their relationship to life history characteristics of this fly

Abstract

Two native trees and one introduced tree in the coast forest ecosystem in southwestern Washington State were identified as new host records for the western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), in 2002 and 2003. Key life history characteristics of flies on or from the new hosts also were examined. Rearing of larvae to adults confirmed native cascara, Rhamnus purshiana DC.; black hawthorn, Crataegus douglasii Lindl.; and introduced cherry laurel, Prunus laurocerasus L., are suitable developmental hosts. In addition, two flies reared from cascara had wing patterns apparently not reported previously, with one keying out to R. indifferens. The numbers of larvae that emerged from fruit of the new hosts and a known host, bitter cherry, Prunus emarginata (Dougl. ex. Hook) D. Dietr., were lower than from fruit of sweet and sour cherries, Prunus avium (L.) L. and Prunus cerasus L. Seasonal patterns of adult abundance in cascara, black hawthorn, and cherry laurel as determined by catches on unbaited sticky yellow panel traps were similar to those in bitter cherry, with most flies caught beginning in mid-July after fruit were no longer green. Fruit of all hosts ripened at similar times. On cascara and black hawthorn, R. indifferens was observed feeding on damaged fruit, and on black hawthorn, flies mated with the non-native apple maggot, Rhagoletis pomonella (Walsh). The longevity of flies reared from cascara, bitter cherry, and sweet and sour cherry was similar, averaging 55.5-83.4 d, and was higher than that of flies reared from cherry laurel, which averaged ≤46.2 d. Body mass of flies from cascara, cherry laurel, and bitter cherry was lower than that of flies from sweet cherry. In contrast to the coast forest ecosystem, neither cascara nor cherry laurel was found at sites studied in ponderosa pine and sagebrush-bunchgrass ecosystems in central Washington in 2003 and 2004. Adults were not caught on unbaited traps in black hawthorns in these two ecosystems, and no larvae were reared from hawthorn fruit from either ecosystem. © 2005 Entomological Society of America.