The role of sulphur compounds for breeding success of Ips typographus L. (Col., Scolytidae) on Norway Spruce (Picea abies [L.] Karst.)

Bark beetles, especially Ips typographus L. represent a severe biotic threat for spruce (Picea abies [L.] Karst.) at low altitudes in Europe. We compared sulphur (total S, SO42−, glutathione, cysteine, methionine), nitrogen (total N, NO3−, total protein, free amino acids), carbon, total phosphorus and PO43−, tree vigour index (TVI) and water content of the phloem after felling, and their dependent changes (tdc) with the breeding success of I. typographus. Twenty trees were classified according to age (34/90 years) and crown density (high/intermediate/low). Water content was higher in young trees than in old trees, higher in the crown than at breast height, and decreased significantly within the 8‐week study period. In old trees, breeding success, length of mother galleries and SO42− were significantly higher, while total protein, NO3− and water content were significantly lower than in young trees. Trees with intermediate crown density provided the best breeding success for I. typographus and had significantly higher arginine content and C/N ratio as well as low amounts of phosphate and glutamine. During the period of bark beetle breeding, total sulphur, glutathione, protein, NO3−, aspartate, glutamine, glutamate, arginine and γ‐aminobutyrate decreased significantly. The results support previous investigations that I. typographus develops best in physiologically weakened trees.