GENETIC-DIVERGENCE AMONG EASTERN NORTH-AMERICAN CONE BEETLES, CONOPHTHORUS (COLEOPTERA, SCOLYTIDAE)

Genetic divergence among populations of cone beetles, Conophthorus banksianae McPherson, C. coniperda (Schwarz), and C. resinosae Hopkins, was assessed by isozyme electrophoretic data. All but one of the eight loci examined were polymorphic, and one locus (Pgi) was sex-linked for C. coniperda. Genotype frequencies generally met Hardy-Weinberg expectations, and fixation index (F(ST)) values indicated low-to-moderate genetic differences among conspecific populations. Fixed allele differences were detected at two loci, Pgi and Dia-2, which separated C. resinosae from C. coniperda, and thus confirmed their specific status established previously by morphological, karyological, and other biochemical characters. Electrophoretic data strongly suggested C. coniperda does not attack red pine cones, and C. resinosae does not attack white pine cones. No diagnostic loci were found to separate C. resinosae from C. banksianae. Phenetic clustering and pairwise comparisons of genetic distance coefficients indicated very little genetic divergence between C. resinosae and C. banksianae. These data were interpreted as failing to reject the null hypothesis that C. resinosae and C. banksianae are one species, an interpretation consistent with available taxonomic evidence from ecological, karyological, and other biochemical characters.