Insect assemblages in Norway spruce (Picea abies (L.) Karst.) stumps in the Eastern Sudetes

Abstract

The aim of the study was to determine the species composition of insect assemblages colonising stumps of Picea abies (L.) Karst. in mountain conditions. Investigations were carried out in the Eastern Sudetes (south -western Po- land) in forest stands situated at 600- 700 m above sea level. The observations were conducted on stumps left behind after felling 70- 90 years old Norway spruces. The analysed stumps were colonised by insects from 21 families of 3 orders: Coleoptera (approximately 95%), Diptera (5%) and Raphidioptera (0.2%). There were 12 Coleoptera families determined with the dominance of Cer- ambycidae (almost 55%) and Curculionidae (37%) including Scolytinae (about 5%). Diptera were represented by 8 families, of which most abundant was the family Rhagionidae (almost 2%) followed by Muscidae (1.4%) and Syr- phidae (1.2%). The order Raphidioptera was represented by 1 family: Raphididae (0.2%). The spruce stumps were mainly colonised by cambio-xylophagous species which added up to 73% of all collect- ed specimens. The European spruce longhorn beetle Tetropium castaneum (L.) was most numerous (15.98 ± 14.99 specimens/stump) of all observed insects as well as it showed the highest permanence of occurrence (97% stumps). Second group with regard to abundance was the genus Hylobius (12.08 ± 20.38 specimen/stump) found in 62% of the observed stumps.