title: How the mountain pine beetle (Dendroctonus ponderosae) breached the Canadian Rocky Mountains.
abstract: The mountain pine beetle (MPB; Dendroctonus ponderosae Hopkins), a major pine forest pest native to western North America, has extended its range north and eastward during an ongoing outbreak. Determining how the MPB has expanded its range to breach putative barriers, whether physical (nonforested prairie and high elevation of the Rocky Mountains) or climatic (extreme continental climate where temperatures can be below -40 °C), may contribute to our general understanding of range changes as well as management of the current epidemic. Here, we use a panel of 1,536 single nucleotide polymorphisms (SNPs) to assess population genetic structure, connectivity, and signals of selection within this MPB range expansion. Biallelic SNPs in MPB from southwestern Canada revealed higher genetic differentiation and lower genetic connectivity than in the northern part of its range. A total of 208 unique SNPs were identified using different outlier detection tests, of which 32 returned annotations for products with putative functions in cholesterol synthesis, actin filament contraction, and membrane transport. We suggest that MPB has been able to spread beyond its previous range by adjusting its cellular and metabolic functions, with genome scale differentiation enabling populations to better withstand cooler climates and facilitate longer dispersal distances. Our study is the first to assess landscape-wide selective adaptation in an insect. We have shown that interrogation of genomic resources can identify shifts in genetic diversity and putative adaptive signals in this forest pest species.
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, CanadaAlberta Biodiversity Monitoring Institute, University of Alberta, Edmonton, AB, Canada janes1@ualberta.ca.
authors.forename: Jasmine K
authors.initials: JK
authors.lastname: Janes
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
authors.forename: Yisu
authors.initials: Y
authors.lastname: Li
authors.affiliation: Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Keeling
authors.affiliation: Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Macaire M S
authors.initials: MM
authors.lastname: Yuen
authors.affiliation: Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, BC, Canada.
authors.forename: Celia K
authors.initials: CK
authors.lastname: Boone
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
authors.forename: Janice E K
authors.initials: JE
authors.lastname: Cooke
authors.affiliation: Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Joerg
authors.initials: J
authors.lastname: Bohlmann
authors.affiliation: Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, BC, Canada.
authors.forename: Dezene P W
authors.initials: DP
authors.lastname: Huber
authors.affiliation: Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, BC, Canada.
authors.forename: Brent W
authors.initials: BW
authors.lastname: Murray
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
authors.forename: David W
authors.initials: DW
authors.lastname: Coltman
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
authors.forename: Felix A H
authors.initials: FA
authors.lastname: Sperling
mesh_terms: D000220:Adaptation, Biological; D000483:Alleles; D000818:Animals; D002170:Canada; D001517:Coleoptera / Q000235:genetics* / Q000502:physiology; D065928:Forests; D005787:Gene Frequency; D014644:Genetic Variation; D049750:Genome, Insect; D020641:Polymorphism, Single Nucleotide; D012641:Selection, Genetic
keywords: connectivity; dispersal; outlier detection; population genetics; structure