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 amo ng the populations ranged from 0.001 to 0.060. The two most southern popula tions were the most differentiated. At two loci, alleles were present in th e southern populations that were not present in any northern populations. T he southern populations were also lacking an allele at one locus that was p resent in all northern populations. Geographic isolation is apparently resp onsible for allowing the divergence of the southern populations. A dendrogr am estimating the relationships among the 10 populations was developed usin g restricted maximum likelihood. Evidence of inbreeding was found, which in these beetles may be closely tied to population size and dispersal behavio r.