title: Do water-limiting conditions predispose Norway spruce to bark beetle attack?
abstract: Drought is considered to enhance susceptibility of Norway spruce (Picea abies) to infestations by the Eurasian spruce bark beetle (Ips typographus, Coleoptera: Curculionidae), although empirical evidence is scarce. We studied the impact of experimentally induced drought on tree water status and constitutive resin flow, and how physiological stress affects host acceptance and resistance. We established rain-out shelters to induce both severe (two full-cover plots) and moderate (two semi-cover plots) drought stress. In total, 18 sample trees, which were divided equally between the above treatment plots and two control plots, were investigated. Infestation was controlled experimentally using a novel 'attack box' method. Treatments influenced the ratios of successful and defended attacks, but predisposition of trees to infestation appeared to be mainly driven by variations in stress status of the individual trees over time. With increasingly negative twig water potentials and decreasing resin exudation, the defence capability of the spruce trees decreased. We provide empirical evidence that water-limiting conditions impair Norway spruce resistance to bark beetle attack. Yet, at the same time our data point to reduced host acceptance by I. typographus with more extreme drought stress, indicated by strongly negative pre-dawn twig water potentials.
authors.affiliation: Institute of Forest Entomology, Forest Pathology and Forest Protection, Department of Forest and Soil Sciences, BOKU - University of Natural Resources and Life Sciences, Hasenauerstr. 38, A-1190, Vienna, Austria.
authors.forename: Sigrid
authors.initials: S
authors.lastname: Netherer
authors.affiliation: Institute of Forest Ecology, Department of Forest and Soil Sciences, BOKU - University of Natural Resources and Life Sciences, Peter-Jordan-Str 82, A-1190, Vienna, Austria.
authors.forename: Bradley
authors.initials: B
authors.lastname: Matthews
authors.affiliation: Institute of Forest Ecology, Department of Forest and Soil Sciences, BOKU - University of Natural Resources and Life Sciences, Peter-Jordan-Str 82, A-1190, Vienna, Austria.
authors.forename: Klaus
authors.initials: K
authors.lastname: Katzensteiner
authors.affiliation: Institute of Forest Entomology, Forest Pathology and Forest Protection, Department of Forest and Soil Sciences, BOKU - University of Natural Resources and Life Sciences, Hasenauerstr. 38, A-1190, Vienna, Austria.
authors.forename: Emma
authors.initials: E
authors.lastname: Blackwell
authors.affiliation: Institute of Botany, Department of Integrative Biology and Biodiversity Research, BOKU - University of Natural Resources and Life Sciences, Gregor-Mendel-Str 33, A-1190, Vienna, Austria.
authors.forename: Patrick
authors.initials: P
authors.lastname: Henschke
authors.affiliation: Institute of Botany, Department of Integrative Biology and Biodiversity Research, BOKU - University of Natural Resources and Life Sciences, Gregor-Mendel-Str 33, A-1190, Vienna, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Hietz
authors.affiliation: Institute of Forest Entomology, Forest Pathology and Forest Protection, Department of Forest and Soil Sciences, BOKU - University of Natural Resources and Life Sciences, Hasenauerstr. 38, A-1190, Vienna, Austria.
authors.forename: Josef
authors.initials: J
authors.lastname: Pennerstorfer
authors.affiliation: Institute of Botany, Department of Integrative Biology and Biodiversity Research, BOKU - University of Natural Resources and Life Sciences, Gregor-Mendel-Str 33, A-1190, Vienna, Austria.
authors.forename: Sabine
authors.initials: S
authors.lastname: Rosner
authors.affiliation: Institute of Botany, Department of Integrative Biology and Biodiversity Research, BOKU - University of Natural Resources and Life Sciences, Gregor-Mendel-Str 33, A-1190, Vienna, Austria.
authors.forename: Silvia
authors.initials: S
authors.lastname: Kikuta
authors.affiliation: Institute of Forest Ecology, Department of Forest and Soil Sciences, BOKU - University of Natural Resources and Life Sciences, Peter-Jordan-Str 82, A-1190, Vienna, Austria.
authors.forename: Helmut
authors.initials: H
authors.lastname: Schume
authors.affiliation: Institute of Forest Entomology, Forest Pathology and Forest Protection, Department of Forest and Soil Sciences, BOKU - University of Natural Resources and Life Sciences, Hasenauerstr. 38, A-1190, Vienna, Austria.
authors.forename: Axel
authors.initials: A
authors.lastname: Schopf
mesh_terms: D000818:Animals; D001317:Austria; D002980:Climate; D001517:Coleoptera / Q000502:physiology*; D004198:Disease Susceptibility; D055864:Droughts; D016014:Linear Models; D028222:Picea / Q000469:parasitology*; D024301:Plant Bark / Q000469:parasitology*; D010935:Plant Diseases / Q000469:parasitology*; D012987:Soil; D013312:Stress, Physiological; D014197:Trees / Q000469:parasitology; D014867:Water / Q000032:analysis / Q000378:metabolism*; D014887:Weather
chemical_list: D012987:Soil; D014867:Water
keywords: Ips typographus; Norway spruce (Picea abies); climate change; defence capability; drought stress; host acceptance; predisposition; tree physiology