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Gnat from Robert Hooke's Micrographia, 1665
A female black fungus gnat

A gnat /ˈnæt/ is any of many species of tiny flying insects in the dipterid suborder Nematocera, especially those in the families Mycetophilidae, Anisopodidae and Sciaridae.[1] They can be both biting and non-biting. Most often they fly in large numbers, called clouds. "Gnat" is a loose descriptive category rather than a phylogenetic or other technical term, so there is no scientific consensus on what constitutes a gnat.

University of Kentucky entomologists consider only non-biting flies to be gnats,[citation needed] and the Institute of Agriculture and Natural Resources of the University of Nebraska–Lincoln classifies fungus gnats and other non-biting flies as gnats.[citation needed] Certain universities also distinguish eye gnats: the Smithsonian Institution describes them as “non-biting flies, no bigger than a few grains of salt, ... attracted to fluids secreted by your eyes”.[2]


Male gnats often assemble in large mating swarms, or ghosts, particularly at dusk.

Gnat larvae are mostly free-living, and some are aquatic. Many feed on plants, though some are carnivorous. Larval plant feeders (such as the Hessian fly larva) cause root, stem, or leaf galls to be formed by the host plant. Some species of fungus gnats (families Mycetophilidae and Sciaridae) are pests of mushrooms and roots of potted plants in homes and greenhouses.

Some South American pleurothallid orchids are pollinated by tiny gnats and have correspondingly small flowers.

The University of Georgia claims that there exists a biting kind of gnat, which is a black fly (buffalo gnat).[3] The scientists compare the painful and vicious bite of the black fly with the fire ant bite. Meanwhile, the North Carolina State University entomologists explain that a widely spread type of biting flies, called biting midges, also belongs to the gnat species: “Biting midges (Culicoides sp.) are small, sometimes barely visible, blood-sucking flies more commonly known in many areas as biting gnats, sand flies, biting midges, punkies or “no-see-ums”.

See also[edit]


  1. ^ "Midges and Gnats | Entomology". Retrieved 2016-09-22.
  2. ^ Gibbons, John. "Gnats Always Keep an Eye Out for a Good Place to Eat". Smithsonian Institution. Retrieved 2018-01-21.
  3. ^ "Houston County Extension ANR | Biting Gnats". Retrieved 2016-09-22.