|Backhaus, S; Wiehl, D; Beierkuhnlein, C; Jentsch, A; Wellstein, C: Warming and drought do not influence the palatability of Quercus pubescens Willd. leaves of four European provenances, Arthropod-Plant Interactions, 8, 329–337 (2014)|
In the context of global warming the impact of extreme drought events on trees and biotic interactions with herbivore insects is widely unknown. A faster range expansion of insects in a changing climate could lead to mass propagations of pests in forests. Therefore, the aim was to investigate the influence of climatic alterations on leaf palatability. We exposed juvenile Quercus pubescens Willd. individuals of four European provenances (Bulgaria, Germany, Hungary, and Italy) to warming and drought. In addition, we conducted a palatability experiment with the pre-exposed Q. pubescens leaves and the caterpillars of the generalist forest pest Lymantria dispar L. (gypsy moth). Consumed leaf dry material, density of trichomes, and specific leaf area were examined. Surprisingly, neither warming nor drought affected the leaf palatability, but palatability was related to the density of trichomes. The Bulgarian provenance of Q. pubescens, which had the lowest density of trichomes, was most palatable. These findings suggest that global warming and drought might not lead to more frequent infestations of the four tested European Q. pubescens provenances by L. dispar caterpillars in the future.