Geographic variation in the effect of lodgepole pine characteristics on mountain pine beetle attacks and productivity in British Columbia.

The mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae: Scolytinae), is the most destructive bark beetle in mature lodgepole pine (Pinus contorta Dougl. Ex Loud.var. latifolia Engelm.) forests in western Canada... The current outbreak in British Columbia is the largest in recorded history... Host factors and historic climate affecting attack dynamics and pupal chamber productivity of MPB on lodgepole pine were examined in southern and north central BC. Trees were felled and intensively sampled in fourteen pine-leading stands. A between-subjects two-by-two factorial ANOVA was conducted to analyze the effects of historic climate and biogeoclimatic subzone on MPB attack and productivity parameters. The effect of dbh on mean gallery start densities was not different between regions, while mean pupal chamber density was significantly higher in areas of historically low climatic suitability than in areas with historically high climatic suitability. Results indicate that north central trees are more suitable for pupal chamber production than southern. Lack of selection pressure in areas of low climatic suitability for mountain pine beetle may be the explanation for this relationship.