Source and spread dynamics of mountain pine beetle in central Alberta, Canada

The mountain pine beetle (Dendroctonus ponderosae Hopkins) (Coleoptera: Curculionidae) is a significant destructive force in the pine forests of western Canada and has the capacity to spread east into a novel host tree species, jack pine (Pinaceae). New populations have been documented in central Alberta, Canada, but the source populations for these outbreaks have yet to be identified. In this study, we use genetic data to identify parent populations for recent outbreak sites near Slave Lake, Lac La Biche, and Hinton, Alberta. We found the northern population cluster that entered Alberta near Grande Prairie was the source of the most eastern established population near Lac La Biche, and the range expansion to this leading-edge population has been too rapid to establish evidence of population structure. However, some dispersal from a population in the Jasper and Hinton area has been detected as far north and east as Slave Lake, Alberta. We also identified two potential source populations for the current outbreak in Hinton: most beetles appear to be from Jasper National Park, Alberta, but some also originated from the northern population cluster. These findings demonstrate the dynamic dispersal capabilities of mountain pine beetle across the Alberta landscape and the potential hazard of increased dispersal to newly established leading-edge populations.