Genetic differentiation at allozyme loci in the Rhagoletis pomonella (Diptera: Tephritidae) species complex

New allozyme frequency data on the Rhagoletis pomonella (Walsh) species group, together with previously published data, are summarized to aid in identification of the species and in estimating the phylogeny of the group. Seven taxa were included in the study: the four described species, one host race or undescribed species infesting Cornus florida L. (flowering dogwood), and two outgroup species, each from a different species group. The phylogenetic tree was estimated by direct parsimony analysis of allele frequencies at 29 enzyme loci. To facilitate comparison with earlier electrophoretic studies, a UPGMA clustering of Nei unbiased genetic distance was also performed. The phylogenetic analysis suggests that two lineages exist in the R. pomonella species group, one consisting solely of R. cornivora Bush, and the other, the remainder of the group, consisting of a complex of extremely similar taxa. Support for the most parsimonious phylogeny is weak. The systematic status of the Cornus florida host-associated population and the evolution of fruit size preference in light of the allozyme phylogeny are discussed.