Vedlevande Coleoptera och Hemiptera förekomst på öar i Kolsnaren i sydvästra Södermanland

Sammanfattning: ABSTRACT Seven islands in the lake Kolsnaren have been investigated. I have inventoried saproxylic insects and investigated what characters on dead wood and characters at the islands that have affected species number of beetles (Coleoptera) and true bugs (Hemiptera). This study shows a relatively low number of species of beetles and true bugs but the study was too small to estimate a proper result. Probably there is many more species, especially more rare/threatened species. The characters vary between islands, but even the individual islands had different tree species, thickness, degradation stage and sun exposure of dead wood. Therefore there were favourable conditions for many different saproxylic species that have different demands of the habitat to find suitable substrate. The islands are partly isolated by water but no longer distances. With that in mind it was important that there is plenty of dead wood with varying characters around Kolsnaren so they get the opportunity to disperse and recolonise the islands when even the habitats are changing in time. The dead woods thickness and degradation stage was the characters with most impact of the number of species.