Diptera feeding as larvae on macrofungi in Finland

During the summers of 1974-1977 about 3700 sporophores of 184 spp. of macrofungi, mainly Agaricales, were examined for infestation with dipterous larvae. Diptera were reared from about 1/3 of the sporophores and positive results were obtained from 148 fungus species. The principal families of fungivorous Diptera were Mycetophilidae (53 spp.) and Anthomyiidae (16 spp.). About 120 spp. of Diptera were recorded. Association with macrofungi has arisen numerous times during evolution in the Diptera; certain fungivorous species are generally saprophagous, others may feed on decomposing matter in the fungus, and among the truly fungivorous species different degrees of specialization are found, in some cases including tendencies towards monophagy. The specialized species belong to Mycetophilidae, Phoridae, Platypezidae, Syrphidae, Anthomyiidae, Fannidae and Muscidae. Developmental and reproductive strategies of fungivorous Diptera as well as protecting strategies by the fungi against the Diptera are discussed. Competition between fungus-feeding dipterous species is probably important in some cases; e.g., from a single sporophore of Leccinum scabrum 12 different Diptera species were reared. The economic importance of the Diptera as pests of edible fungi in Finland is discussed.