caa a22 4500 475838319 CHVBK 20180406123854.0 cr unu---uuuuu 170329e20000401xx s 000 0 eng 10.1007/s101440050013 doi (NATIONALLICENCE)springer-10.1007/s101440050013 Localized outbreak of a willow leaf beetle: plant vigor or natural enemies? [Elektronische Daten] [C. Björkman, B. Bengtsson, H. Häggström] The possible roles of plant quality (vigor) and natural enemies in the development of a localized out-break of the leaf beetle Galerucella lineola (Coleoptera: Chrysomelidae) in a stand of Salix cinerea were investigated. Caged and uncaged larvae on six bushes in the outbreak area were compared with caged and uncaged larvae on six bushes in an adjacent nonoutbreak area in terms of performance. In 1997, when the studies were performed, the natural density of the insect (beetles plus eggs) was six times higher in the outbreak area compared with the nonoutbreak area. Even though the vigor (measured as shoot length) of bushes in the outbreak was 72% higher than that of bushes in the nonoutbreak area, we found no difference between areas in the performance (survival, developmental time, pupal weight) of caged larvae or in the willingness of caged females to lay eggs. Among larvae exposed to natural enemies, the disappearance rate was significantly higher in the nonoutbreak area. The density of generalist predators was significantly higher in the nonoutbreak than in the outbreak area. We conclude that differences in plant quality, despite the observed difference in plant vigor, could not explain the observed difference in beetle density between areas. Lower predation pressure in the outbreak area could, however, not be excluded as a possible reason for the higher density of leaf beetles in this area. The Society of Population Ecology and Springer-Verlag Tokyo, 2000 Key wordsGalerucella lineola nationallicence Salix cinerea nationallicence Performance nationallicence Population dynamics nationallicence Generalist predators nationallicence Host plant quality nationallicence Björkman C. Department of Entomology, Swedish University of Agricultural Sciences, P.O. Box 7044, S-750 07 Uppsala, Sweden Tel. +46 18 67 1532; Fax +46 18 67 2890 e-mail: Christer.Bjorkman@entom.slu.se, SE aut Bengtsson B. Department of Entomology, Swedish University of Agricultural Sciences, P.O. Box 7044, S-750 07 Uppsala, Sweden Tel. +46 18 67 1532; Fax +46 18 67 2890 e-mail: Christer.Bjorkman@entom.slu.se, SE aut Häggström H. Institut de Zoologie, Université de Neuchâtel, Switzerland, CH aut https://doi.org/10.1007/s101440050013 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s101440050013 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Björkman C. Department of Entomology, Swedish University of Agricultural Sciences, P.O. Box 7044, S-750 07 Uppsala, Sweden Tel. +46 18 67 1532; Fax +46 18 67 2890 e-mail: Christer.Bjorkman@entom.slu.se, SE aut NATIONALLICENCE 700 1- Bengtsson B. Department of Entomology, Swedish University of Agricultural Sciences, P.O. Box 7044, S-750 07 Uppsala, Sweden Tel. +46 18 67 1532; Fax +46 18 67 2890 e-mail: Christer.Bjorkman@entom.slu.se, SE aut NATIONALLICENCE 700 1- Häggström H. Institut de Zoologie, Université de Neuchâtel, Switzerland, CH aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer