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genetic variation of lodgepole pine, pinus contorta var. latifolia, chemical and physical defenses that affect mountain pine beetle, dendroctonus ponderosae, attack and tree mortality.plant secondary chemistry is determined by both genetic and environmental factors, and while large intraspecific variation in secondary chemistry has been reported frequently, the levels of genetic variation of many secondary metabolites in forest trees in the context of potential resistance against pests have been rarely investigated. we examined the effect of tree genotype and environment/site on the variation in defensive secondary chemistry of lodgepole pine, pinus contorta var. latifolia, a ...201121845434
Effect of water stress and fungal inoculation on monoterpene emission from an historical and a new pine host of the mountain pine beetle.The mountain pine beetle (Dendroctonus ponderosae, MPB) has killed millions of lodgepole pine (Pinus contorta) trees in Western Canada, and recent range expansion has resulted in attack of jack pine (Pinus banksiana) in Alberta. Establishment of MPB in the Boreal forest will require use of jack pine under a suite of environmental conditions different from those it typically encounters in its native range. Lodgepole and jack pine seedlings were grown under controlled environment conditions and su ...201121874397
Effects of long-term fertilization of forest soils on potential nitrification and on the abundance and community structure of ammonia oxidizers and nitrite oxidizers.Forest fertilization in British Columbia is increasing, to alleviate timber shortfalls resulting from the mountain pine beetle epidemic. However, fertilization effects on soil microbial communities, and consequently ecosystem processes, are poorly understood. Fertilization has contrasting effects on ammonia-oxidizing bacteria and archaea (AOB and AOA) in grassland and agricultural ecosystems, but there are no studies on AOB and AOA in forests. We assessed the effect of periodic (6-yearly applica ...201122066501
comparative phylogeography, genetic differentiation and contrasting reproductive modes in three fungal symbionts of a multipartite bark beetle symbiosis.multipartite symbioses are complex symbiotic relationships involving multiple interacting partners. these types of partnerships provide excellent opportunities in which to apply a comparative approach to identify common historical patterns of population differentiation and species-specific life history traits. using three symbiotic blue-stain fungal species (ophiostomatacea) associated with outbreaking populations of the mountain pine beetle (dendroctonus ponderosae hopkins) in western canada, w ...201121166729
spatial genetic structure of a symbiotic beetle-fungal system: toward multi-taxa integrated landscape genetics.spatial patterns of genetic variation in interacting species can identify shared features that are important to gene flow and can elucidate co-evolutionary relationships. we assessed concordance in spatial genetic variation between the mountain pine beetle (dendroctonus ponderosae) and one of its fungal symbionts, grosmanniaclavigera, in western canada using neutral genetic markers. we examined how spatial heterogeneity affects genetic variation within beetles and fungi and developed a novel int ...201121991309
global and comparative proteomic profiling of overwintering and developing mountain pine beetle, dendroctonus ponderosae (coleoptera: curculionidae), larvae.mountain pine beetles, dendroctonus ponderosae hopkins (coleoptera: curculionidae), are native to western north america, but have recently begun to expand their range across the canadian rocky mountains. the requirement for larvae to withstand extremely cold winter temperatures and potentially toxic host secondary metabolites in the midst of their ongoing development makes this a critical period of their lives.201222982448
phylogeographic insights into an irruptive pest outbreak.irruptive forest insect pests cause considerable ecological and economic damage, and their outbreaks have been increasing in frequency and severity. we use a phylogeographic approach to understand the location and progression of an outbreak by the mpb (dendroctonus ponderosae hopkins), an irruptive bark beetle that has caused unprecedented damage to lodgepole pine forests in western north america and is poised to expand its range across the boreal forest. we sampled mpb populations across britis ...201222837836
dispersal of warren root collar weevils (coleoptera: curculionidae) in three types of habitat.warren root collar weevil, hylobius warreni wood, is a native, flightless insect distributed throughout the boreal forest of north america. it is an emerging problem in young plantings of lodgepole pine, pinus contorta variety latifolia, in western canada, where larval feeding can kill young trees by girdling the root collar. susceptible plantings are becoming more abundant following salvage harvesting and replanting activities in the wake of an ongoing epidemic of mountain pine beetle, dendroct ...201222732616
whitebark pine stand condition, tree abundance, and cone production as predictors of visitation by clark's nutcracker.accurately quantifying key interactions between species is important for developing effective recovery strategies for threatened and endangered species. whitebark pine (pinus albicaulis), a candidate species for listing under the endangered species act, depends on clark's nutcracker (nucifraga columbiana) for seed dispersal. as whitebark pine succumbs to exotic disease and mountain pine beetles (dendroctonus ponderosae), cone production declines, and nutcrackers visit stands less frequently, red ...201222662186
spatial genetic structure of the mountain pine beetle (dendroctonus ponderosae) outbreak in western canada: historical patterns and contemporary dispersal.environmental change has a wide range of ecological consequences, including species extinction and range expansion. many studies have shown that insect species respond rapidly to climatic change. a mountain pine beetle epidemic of record size in north america has led to unprecedented mortality of lodgepole pine, and a significant range expansion to the northeast of its historic range. our goal was to determine the spatial genetic variation found among outbreak population from which genetic struc ...201222554298
transcriptome and full-length cdna resources for the mountain pine beetle, dendroctonus ponderosae hopkins, a major insect pest of pine forests.bark beetles (coleoptera: curculionidae: scolytinae) are major insect pests of many woody plants around the world. the mountain pine beetle (mpb), dendroctonus ponderosae hopkins, is a significant historical pest of western north american pine forests. it is currently devastating pine forests in western north america--particularly in british columbia, canada--and is beginning to expand its host range eastward into the canadian boreal forest, which extends to the atlantic coast of north america. ...201222516182
the legacy of attack: implications of high phloem resin monoterpene levels in lodgepole pines following mass attack by mountain pine beetle, dendroctonus ponderosae hopkins.the mountain pine beetle (dendroctonus ponderosae hopkins) is the most serious pest of pines (pinus) in western north america. host pines protect themselves from attack by producing a complex mixture of terpenes in their resin. we sampled lodgepole pine (pinus contorta variety latifolia) phloem resin at four widely separated locations in the interior of british columbia, canada, both just before (beginning of july) and substantially after (end of august) the mountain pine beetle dispersal period ...201222507014
mountain pine beetle develops an unprecedented summer generation in response to climate warming.the mountain pine beetle (mpb; dendroctonus ponderosae) is native to western north america, attacks most trees of the genus pinus, and periodically erupts in epidemics. the current epidemic of the mpb is an order of magnitude larger than any previously recorded, reaching trees at higher elevation and latitude than ever before. here we show that after 2 decades of air-temperature increases in the colorado front range, the mpb flight season begins more than 1 month earlier than and is approximatel ...201222504550
metabolism and cold tolerance of overwintering adult mountain pine beetles (dendroctonus ponderosae): evidence of facultative diapause?we sought evidence for a distinct diapause in adult overwintering mountain pine beetles (dendroctonus ponderosae hopkins) by measuring metabolic rate and supercooling ability of field collected beetles throughout the year. metabolic rates measured at 0, 5, and 10°c declined significantly from october through november, then rose slowly, reaching levels as high as those recorded in october by late may. from december to february metabolic rates were not correlated with minimum weekly phloem tempera ...201222426083
linking local perceptions to the biophysical and amenity contexts of forest disturbance in colorado.disturbances by insects have considerable effect on the heterogeneity of forested landscapes in north america. responding to calls for bringing human dimensions of landscape disturbance and heterogeneity into ecological assessments and management strategies, this paper explores linkages between biophysical, socioeconomic, and perceptual aspects of a mountain pine beetle (mpb) (dendroctonus ponderosae) outbreak in north central colorado. findings are presented from surveys conducted with resident ...201222270910
spatiotemporal patterns of mountain pine beetle activity in the southern rocky mountains.the current mountain pine beetle (mpb; dendroctonus ponderosae) outbreak in the southern rocky mountains has impacted approximately 750 000 ha of forest. weather and habitat heterogeneity influence forest insect population dynamics at multiple spatial and temporal scales. comparison of forest insect population dynamics in two principal host species may elucidate the relative contribution of weather and landscape factors in initiating and driving extensive outbreaks. to investigate potential driv ...201223185879
characterizing the physical and genetic structure of the lodgepole pine × jack pine hybrid zone: mosaic structure and differential introgression.understanding the physical and genetic structure of hybrid zones can illuminate factors affecting their formation and stability. in north-central alberta, lodgepole pine (pinus contorta dougl. ex loud. var. latifolia) and jack pine (pinus banksiana lamb) form a complex and poorly defined hybrid zone. better knowledge of this zone is relevant, given the recent host expansion of mountain pine beetle into jack pine. we characterized the zone by genotyping 1998 lodgepole, jack pine, and hybrids from ...201223346232
the push-pull tactic for mitigation of mountain pine beetle (coleoptera: curculionidae) damage in lodgepole and whitebark pines.in an attempt to improve semiochemical-based treatments for protecting forest stands from bark beetle attack, we compared push-pull versus push-only tactics for protecting lodgepole pine (pinus contorta douglas ex loudon) and whitebark pine (pinus albicaulis engelm.) stands from attack by mountain pine beetle (dendroctonus ponderosae hopkins) in two studies. the first was conducted on replicated 4.04-ha plots in lodgepole pine stands (california, 2008) and the second on 0.81-ha plots in whitebar ...201223321106
temperature-driven range expansion of an irruptive insect heightened by weakly coevolved plant defenses.warming climate has increased access of native bark beetles to high-elevation pines that historically received only intermittent exposure to these tree-killing herbivores. here we show that a dominant, relatively naïve, high-elevation species, whitebark pine, has inferior defenses against mountain pine beetle compared with its historical lower-elevation host, lodgepole pine. lodgepole pines respond by exuding more resin and accumulating higher concentrations of toxic monoterpenes than whitebark ...201223277541
Population structure and migration pattern of a conifer pathogen, Grosmannia clavigera, as influenced by its symbiont, the mountain pine beetle.We investigated the population structure of Grosmannia clavigera (Gc), a fungal symbiont of the mountain pine beetle (MPB) that plays a crucial role in the establishment and reproductive success of this pathogen. This insect-fungal complex has destroyed over 16 million ha of lodgepole pine forests in Canada, the largest MPB epidemic in recorded history. During this current epidemic, MPB has expanded its range beyond historically recorded boundaries, both northward and eastward, and has now reach ...201222118059
plant species differences in particulate matter accumulation on leaf surfaces.particulate matter (pm) accumulation on leaves of 22 trees and 25 shrubs was examined in test fields in norway and poland. leaf pm in different particle size fractions (pm(10), pm(2.5), pm(0.2)) differed among the species, by 10- to 15-folds at both test sites. pinus mugo and pinus sylvestris, taxus media and taxus baccata, stephanandra incisa and betula pendula were efficient species in capturing pm. less efficient species were acer platanoides, prunus avium and tilia cordata. differences among ...201222554531
contrasting patterns of nucleotide diversity for four conifers of alpine european forests.a candidate gene approach was used to identify levels of nucleotide diversity and to identify genes departing from neutral expectations in coniferous species of the alpine european forest. twelve samples were collected from four species that dominate montane and subalpine forests throughout europe: abies alba mill, larix decidua mill, pinus cembra l., and pinus mugo turra. a total of 800 genes, originally resequenced in pinus taeda l., were resequenced across 12 independent trees for each of the ...201223144662
the relative abundance of mountain pine beetle fungal associates through the beetle life cycle in pine trees.the mountain pine beetle (mpb) is a native bark beetle of western north america that attacks pine tree species, particularly lodgepole pine. it is closely associated with the ophiostomatoid ascomycetes grosmannia clavigera, leptographium longiclavatum, ophiostoma montium, and ceratocystiopsis sp.1, with which it is symbiotically associated. to develop a better understanding of interactions between beetles, fungi, and host trees, we used target-specific dna primers with qpcr to assess the changes ...201222735936
the impact of phloem nutrients on overwintering mountain pine beetles and their fungal symbionts.in the low nutrient environment of conifer bark, subcortical beetles often carry symbiotic fungi that concentrate nutrients in host tissues. although bark beetles are known to benefit from these symbioses, whether this is because they survive better in nutrient-rich phloem is unknown. after manipulating phloem nutrition by fertilizing lodgepole pine trees (pinus contorta douglas var. latifolia), we found bolts from fertilized trees to contain more living individuals, and especially more pupae an ...201222732605
differential effects of plant ontogeny and damage type on phloem and foliage monoterpenes in jack pine (pinus banksiana).coniferous trees have both constitutive and inducible defences that deter or kill herbivores and pathogens. we investigated constitutive and induced monoterpene responses of jack pine (pinus banksiana lamb.) to a number of damage types: a fungal associate of the mountain pine beetle (dendroctonus ponderosae hopkins), grosmannia clavigera (robinson-jeffrey & r.w. davidson); two phytohormones, methyl jasmonate (mj) and methyl salicylate (ms); simulated herbivory; and mechanical wounding. we only i ...201222659460
the geographical and environmental determinants of genetic diversity for four alpine conifers of the european alps.climate is one of the most important drivers of local adaptation in forest tree species. standing levels of genetic diversity and structure within and among natural populations of forest trees are determined by the interplay between climatic heterogeneity and the balance between selection and gene flow. to investigate this interplay, single nucleotide polymorphisms (snps) were genotyped in 24 to 37 populations from four subalpine conifers, abies alba mill., larix decidua mill., pinus cembra l. a ...201223058000
responses of dendroctonus brevicomis (coleoptera: curculionidae) in behavioral assays: implications to development of a semiochemical-based tool for tree protection.currently, techniques for managing western pine beetle, dendroctonus brevicomis leconte (coleoptera: curculionidae, scolytinae), infestations are limited to tree removals (thinning) that reduce stand density and presumably host susceptibility, and/or the use of insecticides to protect individual trees. there continues to be significant interest in developing an effective semiochemical-based tool for protecting trees from d. brevicomis attack, largely as an alternative to conventional insecticide ...201222420267
the role of temperature variability in stabilizing the mountain pine beetle-fungus mutualism.as global climate patterns continue to change and extreme weather events become increasingly common, it is likely that many ecological interactions will be affected. one such interaction is the multipartite symbiosis that exists between the mountain pine beetle and two species of fungi, grosmannia clavigera and ophiostoma montium. in this mutualism, the fungi provide nutrition to the beetle, while the fungi benefit by being dispersed to new host trees. multi-partite mutualisms are predicted to b ...201323791850
the genome and transcriptome of the pine saprophyte ophiostoma piceae, and a comparison with the bark beetle-associated pine pathogen grosmannia clavigera.ophiostoma piceae is a wood-staining fungus that grows in the sapwood of conifer logs and lumber. we sequenced its genome and analyzed its transcriptomes under a range of growth conditions. a comparison with the genome and transcriptomes of the mountain pine beetle-associated pathogen grosmannia clavigera highlights differences between a pathogen that colonizes and kills living pine trees and a saprophyte that colonizes wood and the inner bark of dead trees.201323725015
a mechanistic model for the light response of photosynthetic electron transport rate based on light harvesting properties of photosynthetic pigment molecules.models describing the light response of photosynthetic electron transport rate (etr) are routinely used to determine how light absorption influences energy, reducing power and yields of primary productivity; however, no single model is currently able to provide insight into the fundamental processes that implicitly govern the variability of light absorption. here we present development and application of a new mechanistic model of etr for photosystem ii based on the light harvesting (absorption ...201323138268
bacteria associated with a tree-killing insect reduce concentrations of plant defense compounds.bark beetles encounter a diverse array of constitutive and rapidly induced terpenes when attempting to colonize living conifers. concentrations of these compounds at entry sites can rapidly reach levels toxic to beetles, their brood, and fungal symbionts. large numbers of beetles can overwhelm tree defenses via pheromone-mediated mass attacks, but the mechanisms are poorly understood. we show that bacteria associated with mountain pine beetles can metabolize monoterpenes and diterpene acids. the ...201323807433
a specialized abc efflux transporter gcabc-g1 confers monoterpene resistance to grosmannia clavigera, a bark beetle-associated fungal pathogen of pine trees.grosmannia clavigera is a bark beetle-vectored pine pathogen in the mountain pine beetle epidemic in western north america. grosmannia clavigera colonizes pines despite the trees' massive oleoresin terpenoid defences. we are using a functional genomics approach to identify g. clavigera's mechanisms of adaptation to pine defences. we annotated the abc transporters in the g. clavigera genome and generated rna-seq transcriptomes from g. clavigera grown with a range of terpenes. we functionally char ...201323252416
the cytochromes p450 of grosmannia clavigera: genome organization, phylogeny, and expression in response to pine host chemicals.grosmannia clavigera is a fungal associate of the mountain pine beetle (dendroctonus ponderosae) and a pathogen of lodgepole pine (pinus contorta) that must overcome terpenoid oleoresin and phenolic defenses of host trees. g. clavigera responds to monoterpene influx with complementary mechanisms that include export and the use of these compounds as a carbon source. cytochromes p450 (cyps) may also be involved in the metabolism of host defense compounds. we have identified and phylogenetically cl ...201323111002
pest and disease management: why we shouldn't go against the grain.given the wide range of scales and mechanisms by which pest or disease agents disperse, it is unclear whether there might exist a general relationship between scale of host heterogeneity and spatial spread that could be exploited by available management options. in this model-based study, we investigate the interaction between host distributions and the spread of pests and diseases using an array of models that encompass the dispersal and spread of a diverse range of economically important speci ...201324098739
transcriptome resources and functional characterization of monoterpene synthases for two host species of the mountain pine beetle, lodgepole pine (pinus contorta) and jack pine (pinus banksiana).the mountain pine beetle (mpb, dendroctonus ponderosae) epidemic has affected lodgepole pine (pinus contorta) across an area of more than 18 million hectares of pine forests in western canada, and is a threat to the boreal jack pine (pinus banksiana) forest. defence of pines against mpb and associated fungal pathogens, as well as other pests, involves oleoresin monoterpenes, which are biosynthesized by families of terpene synthases (tpss). volatile monoterpenes also serve as host recognition cue ...201323679205
draft genome of the mountain pine beetle, dendroctonus ponderosae hopkins, a major forest pest.the mountain pine beetle, dendroctonus ponderosae hopkins, is the most serious insect pest of western north american pine forests. a recent outbreak destroyed more than 15 million hectares of pine forests, with major environmental effects on forest health, and economic effects on the forest industry. the outbreak has in part been driven by climate change, and will contribute to increased carbon emissions through decaying forests.201323537049
antennal transcriptome analysis of the chemosensory gene families in the tree killing bark beetles, ips typographus and dendroctonus ponderosae (coleoptera: curculionidae: scolytinae).the european spruce bark beetle, ips typographus, and the north american mountain pine beetle, dendroctonus ponderosae (coleoptera: curculionidae: scolytinae), are severe pests of coniferous forests. both bark beetle species utilize aggregation pheromones to coordinate mass-attacks on host trees, while odorants from host and non-host trees modulate the pheromone response. thus, the bark beetle olfactory sense is of utmost importance for fitness. however, information on the genes underlying olfac ...201323517120
disentangling detoxification: gene expression analysis of feeding mountain pine beetle illuminates molecular-level host chemical defense detoxification mechanisms.the mountain pine beetle, dendroctonus ponderosae, is a native species of bark beetle (coleoptera: curculionidae) that caused unprecedented damage to the pine forests of british columbia and other parts of western north america and is currently expanding its range into the boreal forests of central and eastern canada and the usa. we conducted a large-scale gene expression analysis (rna-seq) of mountain pine beetle male and female adults either starved or fed in male-female pairs for 24 hours on ...201324223726
mountain pine beetles colonizing historical and naive host trees are associated with a bacterial community highly enriched in genes contributing to terpene metabolism.the mountain pine beetle, dendroctonus ponderosae, is a subcortical herbivore native to western north america that can kill healthy conifers by overcoming host tree defenses, which consist largely of high terpene concentrations. the mechanisms by which these beetles contend with toxic compounds are not well understood. here, we explore a component of the hypothesis that beetle-associated bacterial symbionts contribute to the ability of d. ponderosae to overcome tree defenses by assisting with te ...201323542624
an innovative aerial assessment of greater yellowstone ecosystem mountain pine beetle-caused whitebark pine mortality.an innovative aerial survey method called the landscape assessment system (las) was used to assess mountain pine beetle (mpb; dendroctonus ponderosae)-caused mortality of whitebark pine (pinus albicaulis) across the species distribution in the greater yellowstone ecosystem (gye; 894 774 ha). this large-scale implementation of the las method consisted of 8673 km of flight lines, along which 4653 geo-tagged, oblique aerial photos were captured at the catchment level (a subset of 12-digit usgs hydr ...201323634592
persistent reduced ecosystem respiration after insect disturbance in high elevation forests.amid a worldwide increase in tree mortality, mountain pine beetles (dendroctonus ponderosae hopkins) have led to the death of billions of trees from mexico to alaska since 2000. this is predicted to have important carbon, water and energy balance feedbacks on the earth system. counter to current projections, we show that on a decadal scale, tree mortality causes no increase in ecosystem respiration from scales of several square metres up to an 84 km(2) valley. rather, we found comparable decline ...201323496289
population densities and tree diameter effects associated with verbenone treatments to reduce mountain pine beetle-caused mortality of lodgepole pine.mountain pine beetle, dendroctonus ponderosae hopkins (coleoptera: curculionidae: scolytinae), is among the primary causes of mature lodgepole pine, pinus contorta variety latifolia mortality. verbenone is the only antiaggregant semiochemical commercially available for reducing mountain pine beetle infestation of lodgepole pine. the success of verbenone treatments has varied greatly in previous studies because of differences in study duration, beetle population size, tree size, or other factors. ...201323448035
frontalin pheromone biosynthesis in the mountain pine beetle, dendroctonus ponderosae, and the role of isoprenyl diphosphate synthases.the mountain pine beetle (dendroctonus ponderosae hopkins) is the most destructive pest of western north american pine forests. adult males produce frontalin, an eight-carbon antiaggregation pheromone, via the mevalonate pathway, as part of several pheromones that initiate and modulate the mass attack of host trees. frontalin acts as a pheromone, attractant, or kairomone in most dendroctonus species, other insects, and even elephants. 6-methylhept-6-en-2-one, a frontalin precursor, is hypothesiz ...201324167290
cyp345e2, an antenna-specific cytochrome p450 from the mountain pine beetle, dendroctonus ponderosae hopkins, catalyses the oxidation of pine host monoterpene volatiles.the mountain pine beetle (mpb, dendroctonus ponderosae hopkins) is a significant pest of western north american pine forests. this beetle responds to pheromones and host volatiles in order to mass attack and thus overcome the terpenoid chemical defences of its host. the ability of mpb antennae to rapidly process odorants is necessary to avoid odorant receptor saturation and thus the enzymes responsible for odorant clearance are an important aspect of host colonization. an antenna-specific cytoch ...201324139909
evaluations of emamectin benzoate and propiconazole for protecting individual pinus contorta from mortality attributed to colonization by dendroctonus ponderosae and associated fungi.protection of conifers from bark beetle colonization typically involves applications of liquid formulations of contact insecticides to the tree bole. an evaluation was made of the efficacy of bole injections of emamectin benzoate alone and combined with the fungicide propiconazole for protecting individual lodgepole pine, pinus contorta dougl. ex loud., from mortality attributed to colonization by mountain pine beetle, dendroctonus ponderosae hopkins, and progression of associated blue stain fun ...201423868360
mountain pine beetle infestation of lodgepole pine in areas of water diversion.the rocky mountains have experienced extensive infestations from the mountain pine beetle (dendroctonus ponderosae hopkins), affecting numerous pine tree species including lodgepole pine (pinus contorta dougl. var. latifolia). water diversions throughout the rocky mountains transport large volumes of water out of the basins of origin, resulting in hydrologic modifications to downstream areas. this study examines the hypothesis that lodgepole pine located below water diversions exhibit an increas ...201424681362
exo-brevicomin biosynthesis in the fat body of the mountain pine beetle, dendroctonus ponderosae.exo-brevicomin (exo-7-ethyl-5-methyl-6,8-dioxabicyclo[3.2.1]octane) is an important semiochemical for a number of beetle species, including the highly destructive mountain pine beetle, dendroctonus ponderosae. it also has been found in other insects and even in the african elephant. despite its significance, little is known about its biosynthesis. in order to fill this gap and to identify new molecular targets for potential pest management methods, we performed gas chromatography-mass spectromet ...201424532213
exo-brevicomin biosynthetic pathway enzymes from the mountain pine beetle, dendroctonus ponderosae.exobrevicomin (exo-7-ethyl-5-methyl-6,8-dioxabicyclo[3.2.1]octane) is an important semiochemical for a number of beetle species, including the highly destructive mountain pine beetle (dendroctonus ponderosae). it is also found in other insects and the african elephant. despite its significance, very little is known about its biosynthesis. a recent microarray analysis implicated a small cluster of three d. ponderosae genes in exo-brevicomin biosynthesis, two of which had identifiable open reading ...201425138711
efficacy of verbenone and green leaf volatiles for protecting whitebark and limber pines from attack by mountain pine beetle (coleoptera: curculionidae: scolytinae).to develop safe and effective methods to protect whitebark pines, pinus albicaulis engelmann, and limber pines, pinus flexilis james, from attack by mountain pine beetle, dendroctonus ponderosae hopkins (coleoptera: curculionidae), we compared verbenone and verbenone plus green leaf volatiles (glvs) for prevention of beetle attack. we used two strategies: area-wide protection where semiochemical-releasing flakes are dispersed over the forest floor, and individual tree tests where flakes are appl ...201425003785
influence of whitebark pine decline on fall habitat use and movements of grizzly bears in the greater yellowstone ecosystem.when abundant, seeds of the high-elevation whitebark pine (wbp; pinus albicaulis) are an important fall food for grizzly bears (ursus arctos) in the greater yellowstone ecosystem. rates of bear mortality and bear/human conflicts have been inversely associated with wbp productivity. recently, mountain pine beetles (dendroctonus ponderosae) have killed many cone-producing wbp trees. we used fall (15 august-30 september) global positioning system locations from 89 bear years to investigate temporal ...201424963393
how the mountain pine beetle (dendroctonus ponderosae) breached the canadian rocky mountains.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 ...201424803641
comparison of lodgepole and jack pine resin chemistry: implications for range expansion by the mountain pine beetle, dendroctonus ponderosae (coleoptera: curculionidae).the mountain pine beetle, dendroctonus ponderosae, is a significant pest of lodgepole pine in british columbia (bc), where it has recently reached an unprecedented outbreak level. although it is native to western north america, the beetle can now be viewed as a native invasive because for the first time in recorded history it has begun to reproduce in native jack pine stands within the north american boreal forest. the ability of jack pine trees to defend themselves against mass attack and their ...201424688833
factors influencing flight capacity of the mountain pine beetle (coleoptera: curculionidae: scolytinae).the mountain pine beetle, dendroctonus ponderosae hopkins (coleoptera: curculionidae: scolytinae) is the most damaging pest of mature pine (pinaceae) in western north america. although mountain pine beetles have an obligate dispersal phase during which adults must locate a new host for brood production, dispersal is a poorly understood aspect of its ecology. this flight mill study was designed to test the effects of beetle size, sex, and age on flight capacity. energy use during flight was asses ...201424367930
cloning and characterization of chitinases from interior spruce and lodgepole pine.chitinases have been implicated in the defence of conifers against insects and pathogens. cdna for six chitinases were cloned from interior spruce (picea glauca x engelmannii) and four from lodgepole pine (pinus contorta). the cloned interior spruce chitinases were annotated class i pgechia1-1 and pgechia1-2, class ii pgechia2-1, class iv pgechia4-1, and class vii pgechia7-1 and pgechia7-2; lodgepole pine chitinases were annotated class i pcchia1-1, class iv pcchia4-1, and class vii pcchia7-1 an ...201424564978
effects of dwarf mistletoe on stand structure of lodgepole pine forests 21-28 years post-mountain pine beetle epidemic in central oregon.lodgepole pine (pinus contorta) forests are widely distributed throughout north america and are subject to mountain pine beetle (dendroctonus ponderosae) epidemics, which have caused mortality over millions of hectares of mature trees in recent decades. mountain pine beetle is known to influence stand structure, and has the ability to impact many forest processes. dwarf mistletoe (arceuthobium americanum) also influences stand structure and occurs frequently in post-mountain pine beetle epidemic ...201425221963
comparative genomics of the pine pathogens and beetle symbionts in the genus grosmannia.studies on beetle/tree fungal symbionts typically characterize the ecological and geographic distributions of the fungal populations. there is limited understanding of the genome-wide evolutionary processes that act within and between species as such fungi adapt to different environments, leading to physiological differences and reproductive isolation. here, we assess genomic evidence for such evolutionary processes by extending our recent work on grosmannia clavigera, which is vectored by the m ...201424627033
population structure of mountain pine beetle symbiont leptographium longiclavatum and the implication on the multipartite beetle-fungi relationships.over 18 million ha of forests have been destroyed in the past decade in canada by the mountain pine beetle (mpb) and its fungal symbionts. understanding their population dynamics is critical to improving modeling of beetle epidemics and providing potential clues to predict population expansion. leptographium longiclavatum and grosmannia clavigera are fungal symbionts of mpb that aid the beetle to colonize and kill their pine hosts. we investigated the genetic structure and demographic expansion ...201425153489
gene discovery for enzymes involved in limonene modification or utilization by the mountain pine beetle-associated pathogen grosmannia clavigera.to successfully colonize and eventually kill pine trees, grosmannia clavigera (gs cryptic species), the main fungal pathogen associated with the mountain pine beetle (dendroctonus ponderosae), has developed multiple mechanisms to overcome host tree chemical defenses, of which terpenoids are a major component. in addition to a monoterpene efflux system mediated by a recently discovered abc transporter, gs has genes that are highly induced by monoterpenes and that encode enzymes that modify or uti ...201424837377
single-nucleotide polymorphism discovery in leptographium longiclavatum, a mountain pine beetle-associated symbiotic fungus, using whole-genome resequencing.single-nucleotide polymorphisms (snps) are rapidly becoming the standard markers in population genomics studies; however, their use in nonmodel organisms is limited due to the lack of cost-effective approaches to uncover genome-wide variation, and the large number of individuals needed in the screening process to reduce ascertainment bias. to discover snps for population genomics studies in the fungal symbionts of the mountain pine beetle (mpb), we developed a road map to discover snps and to pr ...201424152017
influence of water deficit on the molecular responses of pinus contorta × pinus banksiana mature trees to infection by the mountain pine beetle fungal associate, grosmannia clavigera.conifers exhibit a number of constitutive and induced mechanisms to defend against attack by pests and pathogens such as mountain pine beetle (dendroctonus ponderosae hopkins) and their fungal associates. ecological studies have demonstrated that stressed trees are more susceptible to attack by mountain pine beetle than their healthy counterparts. in this study, we tested the hypothesis that water deficit affects constitutive and induced responses of mature lodgepole pine × jack pine hybrids (pi ...201424319029
developmental mortality increases sex-ratio bias of a size-dimorphic bark beetle.1. given sexual size dimorphism, differential mortality owing to body size can lead to sex-biased mortality, proximately biasing sex ratios. this mechanism may apply to mountain pine beetles, dendroctonus ponderosae hopkins, which typically have female-biased adult populations (2 : 1) with females larger than males. smaller males could be more susceptible to stresses than larger females as developing beetles overwinter and populations experience high mortality. 2. survival of naturally-establish ...201425400320
proteomics indicators of the rapidly shifting physiology from whole mountain pine beetle, dendroctonus ponderosae (coleoptera: curculionidae), adults during early host colonization.we developed proteome profiles for host colonizing mountain pine beetle adults, dendroctonus ponderosae hopkins (coleoptera: curculionidae). adult insects were fed in pairs on fresh host lodgepole pine, pinus contorta dougl. ex loud, phloem tissue. the proteomes of fed individuals were monitored using itraq and compared to those of starved beetles, revealing 757 and 739 expressed proteins in females and males, respectively, for which quantitative information was obtained. overall functional cate ...201425360753
recent mountain pine beetle outbreaks, wildfire severity, and postfire tree regeneration in the us northern rockies.widespread tree mortality caused by outbreaks of native bark beetles (circulionidae: scolytinae) in recent decades has raised concern among scientists and forest managers about whether beetle outbreaks fuel more ecologically severe forest fires and impair postfire resilience. to investigate this question, we collected extensive field data following multiple fires that burned subalpine forests in 2011 throughout the northern rocky mountains across a spectrum of prefire beetle outbreak severity, p ...201425267633
chemical similarity between historical and novel host plants promotes range and host expansion of the mountain pine beetle in a naïve host ecosystem.host plant secondary chemistry can have cascading impacts on host and range expansion of herbivorous insect populations. we investigated the role of host secondary compounds on pheromone production by the mountain pine beetle (dendroctonus ponderosae) (mpb) and beetle attraction in response to a historical (lodgepole pine, pinus contorta var. latifolia) and a novel (jack pine, pinus banksiana) hosts, as pheromones regulate the host colonization process. beetles emit the same pheromones from both ...201424400902
a novel semiochemical tool for protecting pinus contorta from mortality attributed to dendroctonus ponderosae (coleoptera: curculionidae).verbenone (4,6,6-trimethylbicyclo[3.1.1]hept-3-en-2-one) is an antiaggregant of the mountain pine beetle, dendroctonus ponderosae hopkins (coleoptera: curculionidae), a notable forest insect capable of causing extensive levels of tree mortality in western north america. several formulations of verbenone are registered for tree protection, but failures in efficacy are not uncommon, particularly when applied during large infestations. a formulation of (-)-verbenone was developed (specialized phero ...201526470118
temporal dynamics of a commensal network of cavity-nesting vertebrates: increased diversity during an insect outbreak.network analysis offers insight into the structure and function of ecological communities, but little is known about how empirical networks change over time during perturbations. "nest webs" are commensal networks that link secondary cavity-nesting vertebrates (e.g., bluebirds, ducks, and squirrels, which depend on tree cavities for nesting) with the excavators (e.g., woodpeckers) that produce cavities. in central british columbia, canada, northern flicker (colaptes auratus) is considered a keys ...201526230029
integrating models to investigate critical phenological overlaps in complex ecological interactions: the mountain pine beetle-fungus symbiosis.the fates of individual species are often tied to synchronization of phenology, however, few methods have been developed for integrating phenological models involving linked species. in this paper, we focus on mountain pine beetle (mpb, dendroctonus ponderosae) and its two obligate mutualistic fungi, grosmannia clavigera and ophiostoma montium. growth rates of all three partners are driven by temperature, and their idiosyncratic responses affect interactions at important life stage junctures. on ...201525556687
bacteria influence mountain pine beetle brood development through interactions with symbiotic and antagonistic fungi: implications for climate-driven host range expansion.bark beetles are associated with diverse communities of symbionts. although fungi have received significant attention, we know little about how bacteria, and in particular their interactions with fungi, affect bark beetle reproduction. we tested how interactions between four bacterial associates, two symbiotic fungi, and two opportunistic fungi affect performance of mountain pine beetles (dendroctonus ponderosae) in host tissue. we compared beetle performance in phloem of its historical host, lo ...201526037523
effects of temperature on growth, sporulation, and competition of mountain pine beetle fungal symbionts.the mountain pine beetle, dendroctonus ponderosae, depends on two fungi, grosmannia clavigera and ophiostoma montium, to augment a nutrient-poor woody food resource. because the two fungi exert differential effects on the host beetle, temperature-driven differences in fungal growth and competition outcomes have a strong potential to influence host population dynamics. weisolated fungi from beetles and wood from three locations in montana and utah, usa, and measured their growth rates and sporula ...201525773718
pheromone production by an invasive bark beetle varies with monoterpene composition of its naïve host.the secondary chemistry of host plants can have cascading impacts on the establishment of new insect herbivore populations, their long-term population dynamics, and their invasion potential in novel habitats. mountain pine beetle, dendroctonus ponderosae hopkins (coleoptera: curculionidae) has recently expanded its range into forests of jack pine, pinus banksiana lamb., in western canada. we investigated whether variations in jack pine monoterpenes affect beetle pheromone production, as the prim ...201526014128
a model for mountain pine beetle outbreaks in an age-structured forest: predicting severity and outbreak-recovery cycle period.the mountain pine beetle (mpb, dendroctonus ponderosae), a tree-killing bark beetle, has historically been part of the normal disturbance regime in lodgepole pine (pinus contorta) forests. in recent years, warm winters and summers have allowed mpb populations to achieve synchronous emergence and successful attacks, resulting in widespread population outbreaks and resultant tree mortality across western north america. we develop an age-structured forest demographic model that incorporates tempera ...201525976694
mountain pine beetles use volatile cues to locate host limber pine and avoid non-host great basin bristlecone pine.the tree-killing mountain pine beetle (dendroctonus ponderosae hopkins) is an important disturbance agent of western north american forests and recent outbreaks have affected tens of millions of hectares of trees. most western north american pines (pinus spp.) are hosts and are successfully attacked by mountain pine beetles whereas a handful of pine species are not suitable hosts and are rarely attacked. how pioneering females locate host trees is not well understood, with prevailing theory invo ...201526332317
evaluating predators and competitors in wisconsin red pine forests for attraction to mountain pine beetle pheromones for anticipatory biological control.mountain pine beetle, dendroctonus ponderosae hopkins (coleoptera: curculionidae), is an irruptive tree-killing species native to pine forests of western north america. two potential pathways of spread to eastern forests have recently been identified. first, warming temperatures have driven range expansion from british columbia into albertan jack pine forests that are contiguous with the great lakes region. second, high temperatures and drought have fostered largescale outbreaks within the histo ...201526314062
severe white pine blister rust infection in whitebark pine alters mountain pine beetle (coleoptera: curculionidae) attack density, emergence rate, and body size.exotic tree pathogens can cause devastating ecological effects on forests that can be exacerbated when infections increase the likelihood of attack by insects. current high rates of mortality of whitebark pine (pinus albicaulis engelm.) are due to white pine blister rust caused by the exotic fungus, cronartium ribicola j.c. fisch, and the native mountain pine beetle (dendroctonus ponderosae hopkins). these two mortality agents interact in whitebark pine; mountain pine beetle preferentially selec ...201526314009
rapid increases in forest understory diversity and productivity following a mountain pine beetle (dendroctonus ponderosae) outbreak in pine forests.the current unprecedented outbreak of mountain pine beetle (dendroctonus ponderosae) in lodgepole pine (pinus contorta) forests of western canada has resulted in a landscape consisting of a mosaic of forest stands at different stages of mortality. within forest stands, understory communities are the reservoir of the majority of plant species diversity and influence the composition of future forests in response to disturbance. although changes to stand composition following beetle outbreaks are w ...201525859663
variations in foliar monoterpenes across the range of jack pine reveal three widespread chemotypes: implications to host expansion of invasive mountain pine beetle.the secondary compounds of pines (pinus) can strongly affect the physiology, ecology and behaviors of the bark beetles (coleoptera: curculionidae, scolytinae) that feed on sub-cortical tissues of hosts. jack pine (pinus banksiana) has a wide natural distribution range in north america (canada and usa) and thus variations in its secondary compounds, particularly monoterpenes, could affect the host expansion of invasive mountain pine beetle (dendroctonus ponderosae), which has recently expanded it ...201526042134
ectomycorrhizal fungi mediate indirect effects of a bark beetle outbreak on secondary chemistry and establishment of pine seedlings.dendroctonus ponderosae has killed millions of pinus contorta in western north america with subsequent effects on stand conditions, including changes in light intensity, needle deposition, and the composition of fungal community mutualists, namely ectomycorrhizal fungi. it is unknown whether these changes in stand conditions will have cascading consequences for the next generation of pine seedlings. to test for transgenerational cascades on pine seedlings, we tested the effects of fungal inoculu ...201526033270
nonstructural carbohydrate dynamics of lodgepole pine dying from mountain pine beetle attack.bark beetle outbreaks are an important cause of tree death, but the process by which trees die remains poorly understood. the effect of beetle attack on whole-tree nonstructural carbohydrate (nsc) dynamics is particularly unclear, despite the potential role of carbohydrates in plant defense and survival. we monitored nsc dynamics of all organs in attacked and protected lodgepole pines (pinus contorta) during a mountain pine beetle (dendroctonus ponderosae) outbreak in british columbia, starting ...201626256444
polygamy and an absence of fine-scale structure in dendroctonus ponderosae (hopk.) (coleoptera: curcilionidae) confirmed using molecular markers.an understanding of mating systems and fine-scale spatial genetic structure is required to effectively manage forest pest species such as dendroctonus ponderosae (mountain pine beetle). here we used genome-wide single-nucleotide polymorphisms to assess the fine-scale genetic structure and mating system of d. ponderosae collected from a single stand in alberta, canada. fine-scale spatial genetic structure was absent within the stand and the majority of genetic variation was best explained at the ...201626286666
rapid induction of multiple terpenoid groups by ponderosa pine in response to bark beetle-associated fungi.ponderosa pine (pinus ponderosa) is a major and widely distributed component of conifer biomes in western north america and provides substantial ecological and economic benefits. this tree is exposed to several tree-killing bark beetle-microbial complexes, including the mountain pine beetle (dendroctonus ponderosae) and the phytopathogenic fungus grosmannia clavigera that it vectors, which are among the most important. induced responses play a crucial role in conifer defenses, yet these have not ...201626662358
differences in defence responses of pinus contorta and pinus banksiana to the mountain pine beetle fungal associate grosmannia clavigera are affected by water deficit.we tested the hypotheses that responses to the mountain pine beetle fungal associate grosmannia clavigera will differ between the evolutionarily co-evolved host lodgepole pine (pinus contorta var. latifolia) and the naïve host jack pine (pinus banksiana) and that these responses will be influenced by water availability. g. clavigera inoculation resulted in more rapid stem lesion development in lodgepole than in jack pine; water deficit delayed lesion development in both species. decreased hydrau ...201626205849
fatty acid composition of novel host jack pine do not prevent host acceptance and colonization by the invasive mountain pine beetle and its symbiotic fungus.fatty acids are major components of plant lipids and can affect growth and development of insect herbivores. despite a large literature examining the roles of fatty acids in conifers, relatively few studies have tested the effects of fatty acids on insect herbivores and their microbial symbionts. particularly, whether fatty acids can affect the suitability of conifers for insect herbivores has never been studied before. thus, we evaluated if composition of fatty acids impede or facilitate coloni ...201627583820
fungal volatiles can act as carbon sources and semiochemicals to mediate interspecific interactions among bark beetle-associated fungal symbionts.mountain pine beetle (dendroctonus ponderosae) has killed millions of hectares of pine forests in western north america. beetle success is dependent upon a community of symbiotic fungi comprised of grosmannia clavigera, ophiostoma montium, and leptographium longiclavatum. factors regulating the dynamics of this community during pine infection are largely unknown. however, fungal volatile organic compounds (fvocs) help shape fungal interactions in model and agricultural systems and thus may be im ...201627583519
fire severity unaffected by spruce beetle outbreak in spruce-fir forests in southwestern colorado.recent large and severe outbreaks of native bark beetles have raised concern among the general public and land managers about potential for amplified fire activity in western north america. to date, the majority of studies examining bark beetle outbreaks and subsequent fire severity in the u.s. rocky mountains have focused on outbreaks of mountain pine beetle (mpb; dendroctonus ponderosae) in lodgepole pine (pinus contorta) forests, but few studies, particularly field studies, have addressed the ...201627411244
carbon isotopic composition of forest soil respiration in the decade following bark beetle and stem girdling disturbances in the rocky mountains.bark beetle outbreaks are widespread in western north american forests, reducing primary productivity and transpiration, leading to forest mortality across large areas and altering ecosystem carbon cycling. here the carbon isotope composition (δ(13) c) of soil respiration (δj ) was monitored in the decade after disturbance for forests affected naturally by mountain pine beetle infestation and artificially by stem girdling. the seasonal mean δj changed along both chronosequences. we found (a) enr ...201626824577
assessing forest vulnerability to climate warming using a process-based model of tree growth: bad prospects for rear-edges.growth models can be used to assess forest vulnerability to climate warming. if global warming amplifies water deficit in drought-prone areas, tree populations located at the driest and southernmost distribution limits (rear-edges) should be particularly threatened. here, we address these statements by analyzing and projecting growth responses to climate of three major tree species (silver fir, abies alba; scots pine, pinus sylvestris; and mountain pine, pinus uncinata) in mountainous areas of n ...201627782362
photosynthetic limitation of several representative subalpine species in the catalan pyrenees in summer.information on the photosynthetic process and its limitations is essential in order to predict both the capacity of species to adapt to conditions associated with climate change and the likely changes in plant communities. considering that high-mountain species are especially sensitive, three species representative of subalpine forests of the central catalan pyrenees: mountain pine (pinus uncinata mill.), birch (betula pendula roth) and rhododendron (rhododendron ferrugineum l.) were studied und ...201626833754
fortifying the forest: thinning and burning increase resistance to a bark beetle outbreak and promote forest resilience.fire frequency in low-elevation coniferous forests in western north america has greatly declined since the late 1800s. in many areas, this has increased tree density and the proportion of shade-tolerant species, reduced resource availability, and increased forest susceptibility to forest insect pests and high-severity wildfire. in response, treatments are often implemented with the goal of increasing ecosystem resilience by increasing resistance to disturbance. we capitalized on an existing repl ...201627755724
quantitative metabolome, proteome and transcriptome analysis of midgut and fat body tissues in the mountain pine beetle, dendroctonus ponderosae hopkins, and insights into pheromone biosynthesis.bark beetles (coleoptera: scolytinae) are pests of many forests around the world. the mountain pine beetle (mpb), dendroctonus ponderosae hopkins, is a significant pest of western north american pine forests. the mpb is able to overcome the defences of pine trees through pheromone-assisted aggregation that results in a mass attack of host trees. these pheromones, both male and female produced, are believed to be biosynthesized in the midgut and/or fat bodies of these insects. we used metabolite ...201626792242
mountain pine beetle host selection between lodgepole and ponderosa pines in the southern rocky mountains.recent evidence of range expansion and host transition by mountain pine beetle (dendroctonus ponderosae hopkins; mpb) has suggested that mpb may not primarily breed in their natal host, but will switch hosts to an alternate tree species. as mpb populations expanded in lodgepole pine forests in the southern rocky mountains, we investigated the potential for movement into adjacent ponderosa pine forests. we conducted field and laboratory experiments to evaluate four aspects of mpb population dynam ...201626546596
volatile and within-needle terpene changes to douglas-fir trees associated with douglas-fir beetle (coleoptera: curculionidae) attack.mass attack by tree-killing bark beetles (curculionidae: scolytinae) brings about large chemical changes in host trees that can have important ecological consequences. for example, mountain pine beetle (dendroctonus ponderosae hopkins) attack increases emission of terpenes by lodgepole pine (pinus contorta dougl. ex loud.), affecting foliage flammability with consequences for wildfires. in this study, we measured chemical changes to douglas-fir (pseudotsuga menziesii var. glauca (mirb.) franco) ...201627231258
modeling landscape-level spatial variation in sex ratio skew in the mountain pine beetle (coleoptera: curculionidae).through their influence on effective population sizes, sex ratio skew affects population dynamics. we examined spatial variation in female-biased sex ratios in the mountain pine beetle (dendroctonus ponderosae hopkins) outbreak in western canada to better understand how environmental context affects sex ratio skew. our specific objectives were to: 1) characterize spatial variation in mountain pine beetle sex ratio; 2) test previously asserted hypotheses that beetle sex ratio varies with tree dia ...201627209334
aggregation and a strong allee effect in a cooperative outbreak insect.most species that are negatively impacted when their densities are low aggregate to minimize this effect. aggregation has the potential to change how allee effects are expressed at the population level. we studied the interplay between aggregation and allee effects in the mountain pine beetle (dendroctonus ponderosae hopkins), an irruptive bark beetle that aggregates to overcome tree defenses. by cooperating to surpass a critical number of attacks per tree, the mountain pine beetle is able to br ...201627862568
direction of interaction between mountain pine beetle (dendroctonus ponderosae) and resource-sharing wood-boring beetles depends on plant parasite infection.plant pathogens can have cascading consequences on insect herbivores, though whether they alter competition among resource-sharing insect herbivores is unknown. we experimentally tested whether the infection of a plant pathogen, the parasitic plant dwarf mistletoe (arceuthobium americanum), on jack pine (pinus banksiana) altered the competitive interactions among two groups of beetles sharing the same resources: wood-boring beetles (coleoptera: cerambycidae) and the invasive mountain pine beetle ...201626820567
flight period of mountain pine beetle (coleoptera: curculionidae) in its recently expanded range.the ability to predict key phenological events, such as the timing of flight periods, is useful for the monitoring and management of insect pests. we used empirical data to describe the flight period of mountain pine beetle, dendroctonus ponderosae hopkins, in its recently expanded range east of the rocky mountains in canada and developed a degree-day model based on the number of trapped beetles. data were collected over four degrees of latitude and six years. the main flight period, when the mi ...201628028105
sapwood stored resources decline in whitebark and lodgepole pines attacked by mountain pine beetles (coleoptera: curculionidae).recent outbreaks of forest insects have been directly linked to climate change-induced warming and drought, but effects of tree stored resources on insects have received less attention. we asked whether tree stored resources changed following mountain pine beetle (dendroctonus ponderosae hopkins) attack and whether they affected beetle development. we compared initial concentrations of stored resources in the sapwood of whitebark pine (pinus albicaulis engelmann) and lodgepole pine (pinus contor ...201628028093
genetic diversity and population structure of whitebark pine (pinus albicaulis engelm.) in western north america.whitebark pine (wbp, pinus albicaulis engelm.) is an endangered conifer species due to heavy mortality from white pine blister rust (wpbr, caused by cronartium ribicola) and mountain pine beetle (dendroctonus ponderosae). information about genetic diversity and population structure is of fundamental importance for its conservation and restoration. however, current knowledge on the genetic constitution and genomic variation is still limited for wbp. in this study, an integrated genomics approach ...201627992468
climate influences on whitebark pine mortality from mountain pine beetle in the greater yellowstone ecosystem.extensive mortality of whitebark pine, beginning in the early to mid-2000s, occurred in the greater yellowstone ecosystem (gye) of the western usa, primarily from mountain pine beetle but also from other threats such as white pine blister rust. the climatic drivers of this recent mortality and the potential for future whitebark pine mortality from mountain pine beetle are not well understood, yet are important considerations in whether to list whitebark pine as a threatened or endangered species ...201627907251
spatial variability in tree regeneration after wildfire delays and dampens future bark beetle outbreaks.climate change is altering the frequency and severity of forest disturbances such as wildfires and bark beetle outbreaks, thereby increasing the potential for sequential disturbances to interact. interactions can amplify or dampen disturbances, yet the direction and magnitude of future disturbance interactions are difficult to anticipate because underlying mechanisms remain poorly understood. we tested how variability in postfire forest development affects future susceptibility to bark beetle ou ...201627821739
relative importance of climate and mountain pine beetle outbreaks on the occurrence of large wildfires in the western usa.extensive outbreaks of bark beetles have killed trees across millions of hectares of forests and woodlands in western north america. these outbreaks have led to spirited scientific, public, and policy debates about consequential increases in fire risk, especially in the wildland-urban interface (wui), where homes and communities are at particular risk from wildfires. at the same time, large wildfires have become more frequent across this region. widespread expectations that outbreaks increase ex ...201627787956
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