Radiation and divergence in the Rhagoletis Pomonella species complex: inferences from DNA sequence data

Authors


  • Present addresses: A. P. Michel, Department of Entomology, Ohio Agricultural Research and Development Center, Ohio State University, 210 Thorne Hall, 1680 Madison Ave., Wooster, OH 44691, USA. D. Schwarz, Department of Entomology, University of Illinois at Urbana-Champaign, Morrill Hall, 505 S. Goodwin Ave., Urbana, IL 61801, USA. S. Velez, Museum of Comparative Zoology, Harvard University, 26 Oxford St, Cambridge, MA 02138, USA.

  • Data deposition footnote: accession numbers in GenBank for DNA sequences are AY152477AY152526, AY930466AY931013, DQ812553DQ812885 and EU108879EU109174.

Jeffrey L. Feder, Department of Biological Sciences, PO Box 369, Galvin Life Science Center, University of Notre Dame, Notre Dame, IN 46556-0369, USA.
Tel.: +1 574 631 4159; fax: +1 574 631 7413;
e-mail: jfeder@nd.edu

Abstract

Here, we investigate the evolutionary history and pattern of genetic divergence in the Rhagoletis pomonella (Diptera: Tephritidae) sibling species complex, a model for sympatric speciation via host plant shifting, using 11 anonymous nuclear genes and mtDNA. We report that DNA sequence results largely coincide with those of previous allozyme studies. Rhagoletis cornivora was basal in the complex, distinguished by fixed substitutions at all loci. Gene trees did not provide reciprocally monophyletic relationships among US populations of R. pomonella, R. mendax, R. zephyria and the undescribed flowering dogwood fly. However, private alleles were found for these taxa for certain loci. We discuss the implications of the results with respect to identifiable genetic signposts (stages) of speciation, the mosaic nature of genomic differentiation distinguishing formative species and a concept of speciation mode plurality involving a biogeographic contribution to sympatric speciation in the R. pomonella complex.

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