The family Platypezidae (Insecta: Diptera) is a small family (23 genera and 215 species; 71 species from 18 genera are found in North America) of Nearctic flies. Although members of this family are poorly known, it is believed that all species are mycophagous. Recent investigation has found a strong association between individuals of the species Platypeza consobrina and members of the common Basidiomycete macrofungus genus, Agaricus. Most species of Basidiomycete fungi that produce large basidiocarps (mushrooms) serve as hosts for many families of Diptera with mycophagous species (Mycetophilidae, Sciaridae, Drosophilidae, Chloropidae, Phoridae, Cecidomyiidae, Tipulidae, etc.). This does not seem to be the case for species in the genus Agaricus (eg. A. campestris and A. arvensis). These species produce mushrooms in the spring and fall and are utilized almost exclusively by members of the Platypezidae. When examined more closely it was determined that the larvae of platypezids feed on the lamellae (gill) tissue, including basidiospores, as well as other basidiocarp tissue. Basidiospores are retained within the gut of developing larvae, through pupation, and into the adult flies. Reared adult flies and wild flies (caught during oviposition on Agaricus sp. basidiocarps) were found to pass basidiospores within feces. Spores were identified microscopically to be those of A. campestris or A. arvensis. Defecated spores were found to be viable and germinated on Sabaroud-dextrose agar. These findings support the hypothesis that P. consobrina serves as a mutualist vector of Agaricus spores and would likely facilitate outcrossing in natural populations of this mushroom.
Species 1: Diptera Platypezidae Platypeza consobrina
Species 2: Agaricales Agaricaceae Agaricus campestris (field mushroom)
Species 3: Agaricales Agaricaceae Agaricus arvensis (horse mushroom)
Keywords: coevolution, Basidiomycetes
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