Laboulbeniales (Ascomycetes) of Finland and adjacent parts of the U.S.S.R.

Authors: Huldén, Larry
Journal: Karstenia, Volume 23 (1983), Issue 2, pages 31-136.
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Abstract:  About 160 000 specimens of insects, belonging to 1 100 species, and a few millipedes, mostly from museum collections, were investigated with respect to the occurrence of ectoparasitic, laboulbeniaceous fungi in Finland and adjacent parts of the U.S.S.R. In all 166 species of insects (Coleoptera and Diptera) were found to be infested by 88 taxa of Laboulbeniales (81 species from Finland and 42 species from the U.S.S.R.), all are reported from the area for the first time. All the fungus taxa are illustrated and their distribution mapped. Twenty-four taxa are described as new for science: Cantharomyces aploderi n. sp., Dichomyces furcifer subsp. subarcticus n. subsp., Eucantharomyces fennoscandicus n. sp., Fanniomyces copromyzae n. sp., Hydrophilomyces arcuatus n. sp., Laboulbenia carelica n. sp., L. fennica n. sp., L. hastiana n. sp., L. kajanensis n. sp., L. murmanica n. sp., L. oodiphila n. sp., Monoicomyces oxyteli n. sp., Siemaszkoafennica n. sp., Stigmatomyces axystae n. sp., S. bottnica n. sp., S. chthonicus n. sp., S. dichaetae n. sp., S. hackmanii n. sp., S. manicatae n. sp., S. mantis n. sp., S. setacerae n. sp., S. subterraneus n. sp., Symplectromyces lapponicus n. sp. and S. rarus n. sp. Five other species are recorded for the first time from Europe: Laboulbenia compressa Thaxter, L. curtipes Thaxter, L. manubriolata Thaxter, Monoicomyces furcata Thaxter and Teratomyces brevicaulis Thaxter.
A short review is given of the morphology, host-parasite relationships, distribution, origin and taxonomy of the parasites of the Laboulbeniales. The general conditions for the occurrence of laboulbeniaceous parasites are discussed. The frequency of these parasites on insects in Northern Europe proved to be about 1 %, which is very low compared with the values for Central Europe, where the frequency is generally 10-35 %. The explanation appears to be that in the north the host populations are smaller, more scattered and living under more unpredictable climatological conditions, which lowers the probability of establishment, dispersal and survival of the parasites. This is probably also the reason why many parasites do not extend as far north as their hosts, though another explanation may be an alteration in the life cycle pattern of the host towards the north. In one case, at least, viz. Misgomyces dyschirii Thaxter on Dyschirius globosus (Herbst), the distribution of the parasite is apparently directly limited by certain climatological factors.
Preliminary results of investigations of Laboulbenia fennica occurring on whirligig beetles (Coleoptera, Gyrinidae) in several host populations in southern Finland have shown a very constant frequency of the parasite, with no seasonal variation. In contrast, investigations of the Laboulbeniales in Central Europe have revealed two different patterns of population dynamics with distinct seasonal fluctuations.