Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2011
Authors
Jan Bartoš Simen Rød Sandve Roland Kölliker David Kopecký Pavla Christelová Štěpán Stočes Liv Østrem Arild Larsen Andrzej Kilian Odd Arne Rognli Jaroslav DoleželAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
In Norway spruce, the temperature during zygotic embryogenesis appears to adjust an adaptive epigenetic memory in the progeny that may regulate bud phenology and cold acclimation. Conditions colder than normal advance the timing whilst temperatures above normal delay the onset of these processes and altered performance is long lasting in progeny with identical genetic background. As a step toward unraveling the molecular mechanism behind an epigenetic memory, transcriptional analysis was performed on seedlings from seeds of six full-sib families produced at different embryogenesis temperature?cold (CE) vs warm (WE) under long and short day conditions. We prepared two suppressive subtractedcDNAlibraries, forward and reverse, representing genes predominantly expressed in plants from seeds obtained after CE and WE embryogenesis following short day treatment (inducing bud set). Sequencing and annotation revealed considerable differences in the transcriptome of WE versus CE originated plants. By using qRT-PCR we studied the expression patterns of 32 selected candidate genes chosen from subtractive cDNA libraries analysis and nine siRNA pathways genes by a direct candidate approach. Eight genes, two transposons related genes, three with no match to Databases sequences and three genes from siRNA pathways (PaDCL1 and 2, PaSGS3) showed differential expression in progeny from CE andWEcorrelated with the family phenotypic differences. These findingsmaycontribute to our understanding of the epigenetic mechanisms underlying adaptive changes acquired during embryogenesis.
Authors
Vidar Selås Geir Sonerud Erik Framstad John Atle Kålås Sverre Kobro Helge B. Pedersen Tor Kristian Spidsø Øystein WiigAbstract
Grouse and vole numbers may peak after peaks in the seed crop of bilberry (Vaccinium myrtillus) because of reduced levels of feeding deterrents in bilberry plants. We predicted that grouse reproduction depends also on summer (June-September) temperatures in the 2 previous years, because bilberry plants will be less exhausted after a high seed crop in or after warm summers, and thus rebuild their chemical defence more quickly. After berry peak years, population indices of capercaillie (Tetrao urogallus) and bank vole (Myodes glareolus) in southern Norway were negatively related to summer temperatures in the previous year or previous 2 years. Willow grouse (Lagopus lagopus) chick production in five areas in Norway was negatively related to summer temperatures in the 2 previous years when controlling for vole density. A similar pattern was found for the bilberry-feeding moth (Eulithis populata), an important prey for grouse chicks. In eastern Norway, autumn densities of capercaillie and black grouse (Tetrao tetrix) were more likely to peak in vole peak years at high altitudes, where summer temperatures are low. We conclude that high summer temperatures may limit grouse reproduction through the effect on bilberry plants and that a warm climate thus adversely affects population levels of grouse.
Authors
Kyrre Linné Kausrud Jean-Claude Grégoire Olav Skarpaas Nadir Erbilgin Marius Gilbert Bjørn Økland Nils Christian StensethAbstract
Bark beetles (Coleoptera: Curculionidae, Scolytinae) feed and breed in dead or severely weakened host trees. When their population densities are high, some species aggregate on healthy host trees so that their defences may be exhausted and the inner bark successfully colonized, killing the tree in the process. Here we investigate under what conditions participating with unrelated conspecifics in risky mass attacks on living trees is an adaptive strategy, and what this can tell us about bark beetle outbreak dynamics. We find that the outcome of individual host selection may deviate from the ideal free distribution in a way that facilitates the emergence of tree-killing (aggressive) behavior, and that any heritability on traits governing aggressiveness seems likely to exist in a state of flux or cycles consistent with variability observed in natural populations. This may have implications for how economically and ecologically important species respond to environmental changes in climate and landscape (forest) structure. The population dynamics emerging from individual behavior are complex, capable of switching between “endemic” and “epidemic” regimes spontaneously or following changes in host availability or resistance. Model predictions are compared to empirical observations, and we identify some factors determining the occurrence and self-limitation of epidemics.
Abstract
No abstract has been registered
Authors
Kari Bjørneraas Erling Johan Solberg Ivar Herfindal Bram Van Moorter Christer Moe Rolandsen Jean-Pierre Tremblay Christina Skarpe Bernt-Erik Sæther Rune Eriksen Rasmus AstrupAbstract
Copyright © 2011 The Authors. Published under a CC-BY license.
Authors
Julie Nåvik Hval Misty Freeman Kristin Kovar Karen LandmanAbstract
No abstract has been registered
Authors
Ellen Henrikke Aalerud Megan Carroll Shana Hirsch Terence Merritt Luis Sevilla Tarek SolimanAbstract
No abstract has been registered
Abstract
No abstract has been registered