Allozyme diversity and gene flow in the bark beetle, Dendroctonus jeffreyi (Coleoptera: Scolytidae)

Genetic variation within and among 10 California populations of the Jeffrey pine beetle, Dendroctonus jeffreyi Hopkins, was assessed using allozymes. Of 21 loci assayed, 6 were polymorphic in at least one population. Average heterozygosity across all populations and loci was 4%. Genetic distance among the populations ranged from 0.001 to 0.060. The two most southern populations were the most differentiated. At two loci, alleles were present in the southern populations that were not present in any northern populations. The southern populations were also lacking an allele at one locus that was present in all northern populations. Geographic isolation is apparently responsible for allowing the divergence of the southern populations. A dendrogram estimating the relationships among the 10 populations was developed using restricted maximum likelihood. Evidence of inbreeding was found, which in these beetles may be closely tied to population size and dispersal behavior.