Publications

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 ...	2016	27821739
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 ...	2016	27862568
water-deficit and fungal infection can differentially affect the production of different classes of defense compounds in two host pines of mountain pine beetle.	bark beetles are important agents of tree mortality in conifer forests and their interaction with trees is influenced by host defense chemicals, such as monoterpenes and phenolics. since mountain pine beetle (dendroctonus ponderosae hopkins) has expanded its host range from lodgepole pine (pinus contorta doug. ex loud. (var. latifolia engelm.))-dominated forests to the novel jack pine (pinus banksiana lamb.) forests in western canada, studies investigating the jack pine suitability as a host for ...	2016	27881799
novel forest decline triggered by multiple interactions among climate, an introduced pathogen and bark beetles.	novel forest decline is increasing due to global environmental change, yet the causal factors and their interactions remain poorly understood. using tree ring analyses, we show how climate and multiple biotic factors caused the decline of whitebark pine (pinus albicaulis) in 16 stands in the southern canadian rockies. in our study area, 72% of whitebark pines were dead and 18% had partially dead crowns. tree mortality peaked in the 1970s; however, the annual basal area increment of disturbed tre ...	2017	27901296
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 ...	2016	27907251
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 ...	2016	27992468
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 ...	2016	28028093
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 ...	2016	28028105
breeding matters: natal experience influences population state-dependent host acceptance by an eruptive insect herbivore.	eruptive forest insects are highly influential agents of change in forest ecosystems, and their effects have increased with recent climate change. state-dependent life histories contribute significantly to the population dynamics of eruptive forest insect herbivores; however, the proximate mechanisms by which these species shift between states is poorly understood. laboratory bioassays were conducted using the mountain pine beetle (dendroctonus ponderosae) to determine the effect of maternal hos ...	2017	28207862
genetic and genomic evidence of niche partitioning and adaptive radiation in mountain pine beetle fungal symbionts.	bark beetles form multipartite symbiotic associations with blue stain fungi (ophiostomatales, ascomycota). these fungal symbionts play an important role during the beetle's life cycle by providing nutritional supplementation, overcoming tree defences and modifying host tissues to favour brood development. the maintenance of stable multipartite symbioses with seemingly less competitive symbionts in similar habitats is of fundamental interest to ecology and evolution. we tested the hypothesis that ...	2017	28231417
toxicity of monoterpene structure, diversity and concentration to mountain pine beetles, dendroctonus ponderosae: beetle traits matter more.	a high diversity of plant defenses may be a response to herbivore diversity or may be collectively more toxic than single compounds, either of which may be important for understanding insect-plant associations. monoterpenes in conifers are particularly diverse. we tested the fumigant toxicity of four monoterpenes, alone and in combination, to mountain pine beetles, dendroctonus ponderosae, in the context of the beetles' individual body traits. chemical structures of tested monoterpene hydrocarbo ...	2017	28258318
fire, fungi, and beetle influences on a lodgepole pine ecosystem of south-central oregon.	interactions between fire, fungi, bark beetles and lodgepole pines growing on the pumice plateau of central oregon are described. mountain pine beetle (dendroctonus ponderosae) outbreaks occur mainly in forests that are 80-150 years old with a mean diameter of about 25 cm and weakened by a fungus, phaeolus schweinitzii. the outbreak subsides after most of the large diameter trees are killed. the dead trees fuel subsequent fires which return nutrients to the soil, and a new age class begins. the ...	1980	28309679