Bacterial communities associated with mountain pine beetles colonizing lodgepole pine and lodge pole-jack pine hybrids: A potential role in a climate-driven expansion into naïve hosts?

Dendroctonus ponderosae (MPB) populations in Canada have historically been limited to forests west of the Rockies, using lodgepole pine largely as their primary host. With recent climate warming beetles have breached this barrier and now colonize trees east of the Rockies in Alberta, including lodgepole and lodgepole-jack pine hybrids. We characterized bacterial communities associated with MPB colonizing these hosts, and hypothesize symbiotic relationships with microbes are important in this transition between species. Culture-independent analyses support differences in the microbial assemblages among beetles colonizing these different tree hosts. Several microbes were frequently detected across environments, including galleries, regardless of host. The predominant bacteria were Proteobacteria, which in other systems contribute to terpene degradation, nitrogen fixation, and nutrient acquisition. Studies are under way exploring these potential functionalities.