Zeniauskas, R. and Gedminas, A. 2010. Insects Infesting Norway Spruce (Picea abies Karst.) Branches in Clear-cuts and Adjacent Stands.  Baltic Forestry 16 (1): 93-101

For the determination of forest entomofauna migration, the assessment of its distribution is very important. The investigation was carried out in 2004-2006 in in the clear-cuts of Norway spruce (Picea abies Karst.) in Dubrava Experimental and Training Forest Enterprise. The aim of the present work was to estimate the distribution of xylobiont insects breeding under the bark of spruce branches in the clear-cuts and adjacent spruce stands. The assessment of underbark xylobiont insects was made using a method of sample branches and eclector traps. During the research, 1272 spruce branches were examined. A total of 32 insect species in spruce branches were found. The number of phytophagous and entomophagous species was 19 and 11, respectively. The Coleoptera order dominated comprising 93.7% of all xylobiont insects in spruce branches. Pityogenes chalcographus was the most abundant species (75.6% of beetles in total) among the coleopterans. The mean number of phytophages and entomophages was significantly (p≤0.05) 3 times less in the clear-cuts, than in the adjacent stands. Shannon‘s index showed poor species diversity, and was 0.3 (in the clear-cuts) and 1.34 (in adjacent stands). The difference was statistically significant (t≥1.96, p≤0.05). Sorenson‘s similarity measure of xylobiont insects species was 0.51 in the clear-cuts and adjacent stands.

Key words: clear-cut, spruce stand, spruce branches, xylobiont insects, trophic group