Legerdemain in the Fungal Domain: The Use and Abuse of Insects by Fungi

Abstract

An ongoing study of mycophagous Diptera and their mushroom hosts has revealed a close-knit association between species of the dipteran family Platypezidae and species of Agaricus . Platypezid flies and their mushroom hosts may be in the midst of coevolving a symbiosis, to the benefit of both. Adult flies passed viable host's spores within their feces. I postulate that an ovipositing adult female fly could travel from mushroom to mushroom and facilitate sexual reproduction (of the individual mushroom that served as her own larval host) by defecating spores directly onto the basidiocarp that will serve as host for her offspring. This would be of great benefit to the fungus because basidiospores would be deposited close to numerous other spores, potentially of opposite mating type. Without such a vector, dispersal of the mushroom's spores is left to the mercy of the wind currents. Many or even most spores are not dispersed at all and end up deposited directly beneath the parent mushroom, in direct competition with numerous siblings. Few examples of “pseudopollination” of fungi by insects are known in nature. In this article, I review examples of some fungi that “trick” plant pollinators into facilitating their own sexual reproduction.