Epsilon Open Archive

Abstract

Outbreaks of the Spruce bark beetle Ips typographus are often triggered by storm and drought and have destroyed millions of cubic meters of wood. It is therefore a pest insect of economic importance in Europe. Breeding underneath the bark of Norway spruce Picea abies, I. typographus brings blue-stain fungi into the wood which strangles the water uptake and lowers the timber quality. I. typographus (Coleoptera; Scolytinae) and other insects are dependent on the temperature for their metabolism and development. In a future warmer climate we may see increased storm frequencies with larger windthrows serving more breeding material for bark beetles. Further, a higher mean temperature allowing earlier onset of flight of spruce bark beetle in spring, and a faster development from egg to adult, will increase the probability of a second swarming period during the summer and production of a 2nd generation. In a warmer climate higher evaporation will lead to water shortage and increased host susceptibility, especially later during the summer. Thus, an extended (2nd) flight period may lead to more damage to spruce forests. Two generations of the spruce bark beetle is the rule in lower altitude areas of central Europe and in a future climate bivoltinistic behavior is predicted to become more common also in higher altitudes and northward in Scandinavia.