Insect assemblage associated with the polypore Fomitopsis pinicola: a comparison across Fennoscandia

We compiled the data on the insect assemblage occurring within the polypore Fomitopsis pinicola from six regions in Finland, Sweden and Norway. The species composition and diversity of the primary fungivorous beetles (Cisidae and Anobidae) were similar across Fennoscandia. The beetles Cis glabratus Mellie (Cisidae) and C. quadridens Mellie were the most frequent species occurring in 70% and 23% of the fruiting bodies on average. Sulcacis fronticornis (Panzer) and Ennearthron cornutum (Gyllenhal) were relatively common in southern Sweden, while absent from the study regions in Norway and Finland. Similarly, Cis bidentatus (Olivier) and Cis dentatus Mellie were rather common in Norway, but almost absent from the Finnish samples. Species relative abundances in the six study regions exhibit more variation, which to some extent corresponds the biogeographical zones. Our results on the high similarity in species composition indicate deterministic nature of the F. pinicola-associated insect assemblage over large spatial scales. On the other hand, climatic factors probably have an impact on the relative abundance of species.