Mountain Pine Beetle Brood Production in Relation to Thickness of Lodgepole Pine Phloem1

The effects of phloem thickness of lodgepole pine, Pinus contorta Douglas, and number of inches of egg gallery of Dendroctonus ponderosae Hopkins on brood production of the beetle were investigated in laboratory studies. Brood production ranged from an average of 16 beetles for phloem 0.09 inches thick to 94 beetles for phloem 0.23 inches thick. Brood production ranged from about 3 beetles for 10 inches of egg gallery to 130 beetles for 174 inches of egg gallery. When food supply limited production, numbers of emerging brood adults increased linearly with phloem thickness. When food supply did not limit production, numbers of emerging brood adults increased exponentially with an increase in inches of egg gallery.