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

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Abstract
Genetic divergence among populations of cone beetles,Conophthorus banksianaeMcPherson,C.coniperda(Schwarz), andC.resinosaeHopkins, was assessed by isozyme electrophoretic data. All but one of the eight loci examined were polymorphic, and one locus (Pgi) was sex-linked forC.coniperda. Genotype frequencies generally met Hardy-Weinberg expectations, and fixation index (FST) values indicated low-to-moderate genetic differences among conspecific populations. Fixed allele differences were detected at two loci, Pgi and Dia-2, which separatedC.resinosaefromC.coniperda, and thus confirmed their specific status established previously by morphological, karyological, and other biochemical characters. Electrophoretic data strongly suggestedC.coniperdadoes not attack red pine cones, andC.resinosaedoes not attack white pine cones. No diagnostic loci were found to separateC.resinosaefromC.banksianae. Phenetic clustering and pairwise comparisons of genetic distance coefficients indicated very little genetic divergence betweenC.resinosaeandC.banksianae. These data were interpreted as failing to reject the null hypothesis thatC.resinosaeandC.banksianaeare one species, an interpretation consistent with available taxonomic evidence from ecological, karyological, and other biochemical characters.