![Female_black_fungus_gnat](https://upload.wikimedia.org/wikipedia/commons/5/52/Female_black_fungus_gnat.jpg)
A gnat () is any of many species of tiny
flying insects
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of j ...
in the
dipterid suborder
Nematocera
The Nematocera (the name means "thread-horns") are a suborder of elongated flies with thin, segmented antennae and mostly aquatic larvae. This group is paraphyletic and contains all flies but species from suborder Brachycera (the name means "sh ...
, especially those in the families
Mycetophilidae
The Mycetophilidae are 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 i ...
,
Anisopodidae
The Anisopodidae are a small cosmopolitan family of gnat-like flies known as wood gnats or window-gnats, with 154 described extant species in 15 genera, and several described fossil taxa. Some species are saprophagous or fungivorous. They are m ...
and
Sciaridae
The Sciaridae are a family of flies, commonly known as dark-winged fungus gnats. Commonly found in moist environments, they are known to be a pest of mushroom farms and are commonly found in household plant pots. This is one of the least studie ...
.
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
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
or other technical term, so there is no scientific consensus on what constitutes a gnat. Some entomologists consider only non-biting flies to be gnats.
Certain universities and institutes also distinguish
eye gnats: the
Smithsonian Institution
The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded ...
describes them as "non-biting flies, no bigger than a few grains of salt, ... attracted to fluids secreted by your eyes".
Description
As nematoceran flies, adult gnats have antennae with at least six segments that are often long and slender. They are generally slender-bodied with long and narrow wings.
Black fly
A black fly or blackfly (sometimes called a buffalo gnat, turkey gnat, or white socks) is any member of the family Simuliidae of the Culicomorpha infraorder. It is related to the Ceratopogonidae, Chironomidae, and Thaumaleidae. Over 2,200 spec ...
(Simuliidae) and
biting midges
Ceratopogonidae is a family of flies commonly known as no-see-ums, or biting midges, generally in length. The family includes more than 5,000 species, distributed worldwide, apart from the Antarctic and the Arctic.
Ceratopogonidae are Holomet ...
(Ceratopogonidae), also belonging to the gnat category, are small, sometimes barely visible, blood-sucking flies commonly known in many areas as biting gnats, sand flies, punkies or "
no-see-ums
Ceratopogonidae is a family of flies commonly known as no-see-ums, or biting midges, generally in length. The family includes more than 5,000 species, distributed worldwide, apart from the Antarctic and the Arctic.
Ceratopogonidae are holomet ...
", among other names.
Life cycle
In general, gnats go through the four life stages of egg, larva, pupa and adult,
similar to other flies.
The fungus gnats lay their eggs in moist organic debris or soil, which hatch into larvae. The larvae feed on organic matter such as leaf mold, mulch, compost, grass clippings, root hairs and fungi. They eventually become pupae and then adults emerge from the pupae. At a temperature of 75 ºF (23.9 ºC), the cycle takes approximately 17 days: 3 days as eggs, 10 days as larvae and 4 days as pupae. Warmer temperatures allow more rapid development.
Some species of fungus gnats (e.g. those in genus ''
Bradysia
''Bradysia'' is a genus of fungus gnat in the family Sciaridae.a They are commonly known as darkwinged fungus gnats. They are considered a major pest in greenhouse agriculture because they thrive in the moist conditions common inside greenhouses ...
'') are pests of
mushrooms
A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans.
The standard for the name "mushroom" is ...
and roots of plants in
greenhouses
A greenhouse (also called a glasshouse, or, if with sufficient heating, a hothouse) is a structure with walls and roof made chiefly of transparent material, such as glass, in which plants requiring regulated climatic conditions are grown.These s ...
.
Other gnats begin their lives as eggs laid in masses in water, or laid on aquatic plants. The aquatic larvae dwell in ponds, pools, water-filled containers, clogged rain gutters or wet soil, which generally feed on plant matter (living or dead). The larvae develop into pupae and then into adults. Adults live only long enough to reproduce and they may form large mating
swarms, often around dusk. The life cycle generally takes 4-5 weeks.
The larvae of most gall gnats (
Cecidomyiidae
Cecidomyiidae is a family of flies known as gall midges or gall gnats. As the name implies, the larvae of most gall midges feed within plant tissue, creating abnormal plant growths called galls. Cecidomyiidae are very fragile small insects us ...
), such as the
Hessian fly
The Hessian fly or barley midge, ''Mayetiola destructor'', is a species of fly that is a significant pest of cereal crops including wheat, barley and rye. Though a native of Asia, upon its discovery it was believed to have been transported into N ...
larva, form
galls
Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths of plant tissues, similar to be ...
in flowers, leaves, stems, roots or other plant parts.
Pollination
Some
South American
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
pleurothallid orchids
Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant.
Along with the Asteraceae, they are one of the two largest families of flowering ...
are pollinated by tiny gnats and have correspondingly small
flowers
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...
.
Control
Adult non-biting gnats do not damage plants but are considered a nuisance. Usually, larvae do not cause serious plant damage, but when present in large numbers can stunt the plant growth and damage its roots.
To prevent gnats from spreading, measures have to be taken to target immature stages of development of the
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
. Physical tactics include eliminating favorable living conditions: reduction of excess moisture, drainage of pools with standing water, and removal of decaying organic matter.
Commercially available control agents and insecticides can be used as a control measure, but are not recommended for use in a household.
To control adult gnats in smaller areas, pressurized aerosol sprays with
pyrethrins
The pyrethrins are a class of organic compounds normally derived from '' Chrysanthemum cinerariifolium'' that have potent insecticidal activity by targeting the nervous systems of insects. Pyrethrin naturally occurs in chrysanthemum flowers and i ...
can be used.
Other control measures in the household can include turning off unnecessary lights at dusk and sealing vents and other openings.
See also
*
Black fly
A black fly or blackfly (sometimes called a buffalo gnat, turkey gnat, or white socks) is any member of the family Simuliidae of the Culicomorpha infraorder. It is related to the Ceratopogonidae, Chironomidae, and Thaumaleidae. Over 2,200 spec ...
*
Enicocephalidae
Enicocephalidae, also called unique-headed bugs and gnat bugs, are a family of around 300 species of the suborder Heteroptera. They are typically 4 mm long, and found throughout the world. They have an elongated head, constricted in places, ...
(gnat bugs)
*
Cecidomyiidae
Cecidomyiidae is a family of flies known as gall midges or gall gnats. As the name implies, the larvae of most gall midges feed within plant tissue, creating abnormal plant growths called galls. Cecidomyiidae are very fragile small insects us ...
(gall gnats)
*
Sciaridae
The Sciaridae are a family of flies, commonly known as dark-winged fungus gnats. Commonly found in moist environments, they are known to be a pest of mushroom farms and are commonly found in household plant pots. This is one of the least studie ...
(dark-winged fungus gnats)
*
Ceratopogonidae
Ceratopogonidae is a family of flies commonly known as no-see-ums, or biting midges, generally in length. The family includes more than 5,000 species, distributed worldwide, apart from the Antarctic and the Arctic.
Ceratopogonidae are holomet ...
*
Midge
*
Mosquito
Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...
*
Sandfly
Sandfly (or sand fly) is a colloquial name for any species or genus of flying, biting, blood-sucking dipteran (fly) encountered in sandy areas. In the United States, ''sandfly'' may refer to certain horse flies that are also known as "greenhea ...
References
{{reflist
Nematocera
Insect common names