Analysis of mitochondrial DNA and morphological characters in the subtribe Carpomyina (Diptera: Tephritidae)

Abstract

The phylogenetic relationships of 43 species in the subtribe Carpomyina (39 <em>Rhagoletis </em>spp., plus <em>Carpomya schineri </em>(Loew), <em>Oedicarena latifrons </em>(Wulp), <em>Rhagoletotrypeta pastranai </em>Aczél, and <em>Zonosemata electa </em>(Say)) are examined using morphological and mitochondrial DNA (mtDNA) characters. The taxon sample includes 5 Palearctic <em>Rhagoletis </em>species (<em>R. almatensis </em>Rohdendorf, <em>R. batava </em>Hering, <em>R. flavicincta </em>(Loew), <em>R. flavigenualis </em>Hering, and <em>R. magniterebra </em>(Rohdendorf)) and 5 Neotropical <em>Rhagoletis </em>species (<em>R. blanchardi </em>Aczél, <em>R. ferruginea </em>Hendel, <em>R. lycopersella </em>Smyth, <em>R. nova </em>(Schiner), and <em>R. psalida </em>Hendel) whose mtDNA relationships have not been previously analyzed. Phylogenetic analysis of 77 morphological features using unweighted parsimony yielded 28,671 most parsimonious reconstructions (MPRs). A strict consensus of these MPRs contained 12 clades, and further analysis using successive approximations improved phylogenetic resolution. Analysis of 1027 aligned nucleotide positions in the mitochondrial COI/COII region indicated that, as previously hypothesized, the genus <em>Rhagoletis </em>may not be strictly monophyletic. Monophyly of <em>Rhagoletis</em>, in the strict holophyletic sense (<em>sensu </em>Hennig), was disrupted by <em>Z. electa </em>and <em>C. schineri</em>; however, these phylogenetic placements did not have bootstrap support. Analysis of mtDNA supported our previous hypothesis that <em>R. batava </em>and <em>R. flavigenualis </em>have phylogenetic affinity to five taxonomically-defined North American species groups. In addition, mtDNA data grouped <em>R. almatensis </em>and <em>R. flavicincta </em>with <em>R. cerasi </em>(L.), a result consistent with our present analysis of morphology. Analyses of both morphology and mtDNA place <em>R. magniterebra </em>as a sister taxon to <em>R. meigenii </em>(Loew). The Neotropical <em>Rhagoletis </em>species form a distinct group based on mtDNA analysis and, with the exception of the placement of <em>Rh. pastranai</em>, these relationships are consistent with morphology. Several clades observed in the morphological analysis were in conflict with those observed in the mtDNA analysis. Partition homogeneity tests indicated that significantly different phylogenetic signals emanate from the morphological and mtDNA data; therefore these data sets were not combined for analysis. Recent phylogenetic analyses of several <em>Rhagoletis </em>spp. based on DNA sequences of alleles at anonymous nuclear loci indicate that random genetic drift and/or hybridization and introgression may be playing a large role in the evolution of <em>Rhagoletis </em>species. We argue that these forces, combined with differential selection, can lead to fixation of alternate alleles in different lineages and result in the phylogenetic conflicts observed in the morphological and mtDNA analyses.