Fungus gnats

Definition

Small, delicate, short-lived flies (Diptera) of the superfamily Sciaroidea, comprising families Sciaridae, Diadocidiidae, Ditomyiidae, Keroplatidae, Bolitophilidae, and Mycetophilidae, with larvae that typically develop in decaying organic matter, fungi, or damp soils. Adults are weak fliers with long, segmented antennae; larvae are slender, pale, and often feed on fungal hyphae, though some Keroplatidae are predatory on other small invertebrates. The group is ecologically significant as decomposers, fungal spore dispersers, and occasional pests in greenhouses and mushroom cultivation.

Etymology

From Latin fungus (fungus) + gnat (small biting fly), reflecting larval association with fungal substrates

Example

Bradysia species (Sciaridae) are common fungus gnats whose larvae damage seedling roots in greenhouse potting media, while some Keroplatidae larvae spin sticky silk threads to capture springtails and other prey in caves and forest litter.

Synonyms

• sciarid flies
• mushroom gnats

Related Terms

• Sciaridae
• Keroplatidae
• Mycetophilidae
• mycophagy
• saprotrophic
• greenhouse pests
• Fungivory
• Sciaroidea

Usage Notes

Not a formal taxon but a functional-ecological grouping of six families; 'fungus gnat' is sometimes applied more narrowly to Sciaridae alone in agricultural contexts. Contrast with crane flies (Tipuloidea) and gall midges (Cecidomyiidae), which occupy similar moist habitats but belong to different superfamilies. Lygistorrhinidae (long-beaked fungus gnats) are sometimes included in expanded definitions.