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, Anisopodidae and Sciaridae. 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 ...

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". Found ...

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 spe ...

(Simuliidae) and biting midges (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", 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'') 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 ...

. 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 ...

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 appropriat ...

. 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 can be used. Other control measures in the household can include turning off unnecessary lights at dusk and sealing vents and other openings.

References

{{reflist Nematocera Insect common names

Description

Life cycle

Pollination

Control

See also

References