Polypores of western Finnish Lapland and seasonal dynamics of polypore beetles

Authors: Schigel, Dmitry S. & Niemelä, Tuomo & Kinnunen, Juha
Journal: Karstenia, Volume 46 (2006), Issue 2, pages 37-64.
Doi: https://doi.org/10.29203/ka.2006.415
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Key words: Basidiomycota, ecology, Coleptera, Finland, Lapland, basidiocarp, saproxylic, sporulation, fungivory

Abstract: The paper summarizes field inventories of polypores and associated beetles in northwestern Finland (Lapland) in the years 2001–2004. The research area includes nearvirgin or old-growth forests of the Pallas–Yllästunturi National Park and the Pisavaara Strict Nature Reserve, one of the largest areas of protected forests in the country. Altogether 132 polypore species were found or (a few) documented from herbarium collections. Special attention was paid to those beetles that visit or inhabit polypores, either to consume their spores and mycelium, or living in polypore basidiocarps at larval stages. Beetle species compositions and their occurrences as larvae versus imagines differed according to the characteristics of polypore basidiomata. Four kinds (life cycles) of basidiomata were separated: ephemeral, annual sturdy, annual hibernating, and perennial. The selective effect of these life cycles over attracted beetles is extensively discussed with numerous examples. Parallels were found between the insects living in decayed wood versus mushrooms: while beetles of the ephemeral polypore hosts follow in their biology the “mushroom” pathway (pupating in soil debris), those living in perennial basidiocarps follow the “wood” pathway in both consuming the fungus and in pupating inside the decaying basidiocarp. The paper includes complete lists of polypores and polypore-linked beetles found in the study area. A number of wood-inhabiting fungi of other groups are listed, including observations of their beetle fauna. Also more theoretical aspects of the fungus–beetle interaction are discussed.