Genetic Relationships between Two Sibling Species of Bark Beetle (Coleoptera: Scolytidae), Jeffrey Pine Beetle and Mountain Pine Beetle, in Northern California1

Abstract

The genetic relationship between two sibling bark beetle species from northern California, the Jeffrey pine beetle, Dendroctonus jeffreyi Hopkins, and the mountain pine beetle, D.ponderosae Hopkins, was examined by electrophoresis. The genetic differences found between the Jeffrey pine beetle and the mountain pine beetle support their current designation as separate species. Two gene loci were fixed for different alleles in the two groups and provide strong evidence that gene flow does not occur between them. At several other loci, less striking but nevertheless significant differences were observed. The level of overall genetic similarity between the Jeffrey pine beetle and the mountain pine beetle was much lower than that found between conspecific populations of either group.