Phenological attributes and phylogenetic relationships of Rhagoletis juniperina Marcovitch (Diptera: Tephritidae) in the Great Lakes region

Rhagoletis juniperina Marcovitch (Diptera: Tephritidae) infests Eastern Red Cedar (Juniperus virginiana L.) and other North American junipers. While several Rhagoletis species are of interest as orchard crop pests (apple maggot, blueberry maggot, cherry fruit fly) and as models for studying speciation (R. pomonella Walsh species group), R. juniperina is of interest because it may tie together evolutionarily the Nearctic and Palearctic Rhagoletis fauna. One goal of this study was to test two competing hypotheses first proposed by Bush (1966): i) that R. juniperina is more closely related to the Nearctic dogwood-infesting R. tabellaria (Fitch), to which it is morphologically similar; or ii) that R. juniperina is more closely related to the Eurasian juniper-infesting R. flavigenualis Hering. To study R. juniperina, which is rarely collected, we first established a local study site by collecting juniper berries from several sites in the Lansing, MI vicinity in fall 2010, finding a heavily-infested juniper tree on the Michigan State University campus. Preliminary mitochondrial COII sequences of reared pupae matched (99.8%) the R. juniperina COII sequence in GenBank, allowing tentative identification of these flies as R. juniperina. Subsequently, the morphology of adults reared from these pupae the following spring and summer confirmed this diagnosis. Phenological attributes of the Farm Lane Bridge population were determined via weekly fruit collections in fall 2011 and 2012, and “peak” larval infestation was found to occur during the first part of October, while mean post-diapause eclosion time was found to be approximately 103 days. Rhagoletis juniperina adults were also reared from infested junipers found in Wisconsin and North Carolina, indicating that the geographic range of R. juniperina on J. virginiana is broader than previously thought. Hymenopteran parasitoids of R. juniperina were also observed; both the egg parasitoid, Utetes juniperi (Fischer) (Hymenoptera: Branconidae), and a new pupal parasitoid (Coptera n. sp.) (Hymenoptera: Diapriidae) were reared from fruit and pupae, respectively, collected at the MSU campus site. Subsequent phylogenetic analyses based on mitochondrial COI sequences did not resolve the relationships of R. juniperina and R. pomonella or flies in the Rhagoletis tabellaria species group. The sole R. flavigenualis individual in our sample was placed sister to an unresolved trichotomy of three clades containing these Nearctic taxa. The analysis also revealed within-species haplotype variability in R. juniperina, with a 3.8% nucleotide sequence difference observed between COI sequences of the flies from MI, WI, and NC compared to the Ontario R. juniperina sequences in the Barcode of Life database. © 2015. The Michigan Entomological Society