Fungus Gnats

Mycetophilidae is a family of small flies, forming the bulk of those species known as fungus gnats. About 3000 described species are placed in 150 genera, but the true number of species is undoubtedly much higher. They are generally found in the damp habitats favoured by their host fungi and sometimes form dense swarms.

Adults of this family can usually be separated from other small flies by the strongly humped thorax, well-developed coxae, and often spinose legs, but identification within the family between genera and species generally requires close study of microscopic features such as subtle differences in wing venation and variation in chaetotaxy and genitalia. The terrestrial larvae usually feed on fungi, especially the fruiting bodies, but also spores and hyphae, but some species have been recorded on mosses and liverworts. The larvae of some species, while still being associated with fungi, are at least partly predatory. Some species are attracted to the fungal odor let off by plants like Jack-in-the-Pulpit, and end up pollinating them in their search for food.