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.
2012
Authors
DJ Sargent T Passey N Surbanovski E. Lopez Girona P Kuchta Jahn Davik R. Harrison A Passey AB Whitehouse DW SimpsonAbstract
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Authors
Romain Larbat Kristine Marie Olsen Rune Slimestad Trond Karsten Løvdal Camille Bénard Michel Verheul Frédéric Bourgaud Christophe Robin Cathrine LilloAbstract
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Authors
Jack D'Arcy Evgenia Dunaevskaya J.W. Treasurer Oddvar Ottesen Julie Maguire Nonna Zhuravleva Åsbjørn Karlsen Celine Rebours Richard FitzgeraldAbstract
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The aim of this experiment was to investigate the effect of increasing the number of ewes per nipple drinker on water intake, feed intake and drinking behaviour of ewes. A group of 30 1¾ year old, pregnant ewes of the Norwegian Dala breed were exposed to three treatments, each treatment lasting one week: 7.5 ewes per nipple drinker (N7.5: four nipple drinkers), 15 ewes per nipple drinker (N15: two nipple drinkers) and 30 ewes peer nipple drinker (N30: one nipple drinker). The experiment was performed both in January (week 4–6, replicate 1) and replicated in April (week 13–15, replicate 2). The ewes were kept in insulated building and had free access to good quality hay. Water metres were connected to the pipeline for water supply and water wastage was collected and weighed. In addition, the daily intake of hay was recorded and the ewes were video recorded the three last days of each experimental period. Total drinking time per individual was calculated from observations of drinking behaviour from the video, as were also incidents of queuing and displacements. Both water and feed intake was higher in replicate 2 than in replicate 1. Increasing the number of individuals per nipple drinker had no effect on water intake in replicate 1, whereas in replicate 2 the water intake was (mean±SE) 3.5±0.3; 4.2±0.1 and 4.9±0.1 l/ewe and day in the treatments N7.5, N15 and N30, respectively (P<0.05). Regardless of replicate, the time spent drinking increased significantly when number of ewes per nipple drinker increased. Queuing was not affected by increasing the number of ewes per nipple drinker. In replicate 1 the number of displacements increased significantly when the number of individuals per nipple drinker increased (N7.5=7.6±1.7; N15=15.0±4.2 and N30=36.7±5.2; P<0.05) and the same trend could be seen in replicate 2, although not significant. In conclusion, one nipple drinker with an acceptable flow rate can serve up to 30 ewes without negatively affecting water and feed intake
Authors
Christian Schiebe Almuth Hammerbacher Göran Birgersson Johanna Witzell Peter E. Brodelius Jonathan Gershenzon Bill S. Hansson Paal Krokene Fredrik SchlyterAbstract
Secondary attraction to aggregation pheromones plays a central role in the host colonization behavior of the European spruce bark beetle Ips typographus. However, it is largely unknown how the beetles pioneering an attack locate suitable host trees, and eventually accept or reject them. To find possible biomarkers for host choice by I. typographus, we analyzed the chemistry of 58 Norway spruce (Picea abies) trees that were subsequently either (1) successfully attacked and killed, (2) unsuccessfully attacked, or (3) left unattacked. The trees were sampled before the main beetle flight in a natural Norway spruce-dominated forest. No pheromones were used to attract beetles to the experimental trees. To test the trees’ defense potential, each tree was treated in a local area with the defense hormone methyl jasmonate (MeJ), and treated and untreated bark were analyzed for 66 different compounds, including terpenes, phenolics and alkaloids. The chemistry of MeJ-treated bark correlated strongly with the success of I. typographus attack, revealing major chemical differences between killed trees and unsuccessfully attacked trees. Surviving trees produced significantly higher amounts of most of the 39 analyzed mono-, sesqui-, and diterpenes and of 4 of 20 phenolics. Alkaloids showed no clear pattern. Differences in untreated bark were less pronounced, where only 1,8-cineole and (−)-limonene were significantly higher in unsuccessfully attacked trees. Our results show that the potential of individual P. abies trees for inducing defense compounds upon I. typographus attack may partly determine tree resistance to this bark beetle by inhibiting its mass attack.