Phylogenetic analysis of North American Rhagoletis (Diptera: Tephritidae) and related genera using mitochondrial DNA sequence data.

Partial sequences (approximately 850 bp) of the mitochondrial 16S ribosomal RNA gene were determined for 21 members of the fruit fly genus Rhagoletis and 6 related tephritid taxa by sequencing DNA amplified by the polymerase chain reaction. Sequences were highly A + T rich, with an average G + C content of 19.2%. Sequence divergence ranged from 0 to 11.7% among the included taxa. Sequences were used to reconstruct the phylogeny of this group of flies with neighbor-joining and maximum parsimony methods. A group of 18 North American Rhagoletis species formed a monophyletic clade, and three morphologically based species groups were identified with strong statistical support. Relationships among the species groups were partially resolved. The tabellaria species group appears to be paraphyletic with respect to the pomonella species group, in contrast to previous allozyme analyses that united the cingulata and pomonella groups. The relations of the North American clade to other genera within the tribe Carpomyini were not clearly resolved. Rhagoletis striatella, a North American species that uses members of the tomato family (Solanaceae) as a larval host, may be more closely associated with South American Rhagoletis species and related genera than with the other North American Rhagoletis species.