Do Gnats Bite?

Can gnats bite humans?

Insect common names are often tricky, confusing and overly inclusive. While it is correct to say that gnats bite, unquestionably not all gnats have the kind of mouthparts that enable them to bite and penetrate the skin.

Biting Gnats Description

Biting gnats have six legs, two prominent wings and are extremely small. They feed on hosts either individually or in swarms and use the cutting teeth of their mouthparts to puncture and cut their host’s skin to expose blood that is sucked into their digestive system. Female biting gnats feed on blood, while the males feed on plant nectar and do not bite. Consuming blood is mandatory for female biting gnats to produce eggs that will properly develop.

Bites are most likely to occur on any exposed, uncovered skin and most often occur on the head, neck, forearms, hands, face, legs and feet. General symptoms are itchiness, irritation, redness and swelling at the site of the bite.

The itching associated with gnat bites is due to the host’s reaction to anticoagulant compounds that allow gnats to suck blood without the blood coagulating. Continuous scratching can lead open sores that are susceptible to secondary bacterial infection of the bite wound. In some cases, the transmission of infectious diseases by the biting gnat is possible.

Since gnat bites can lead to various medical problems, be sure to see your family doctor or other health professional if symptoms continue or become worse over time.

Some Commonly Encountered Biting Gnats

Biting Midges (Family Ceratopogonidae)

Biting midges in this family are commonly called punkies, no-see-ums, sand gnats and flying teeth. They are grayish in color, but after taking a blood meal are likely to be reddish in appearance. They are only about 1/25- 1/8 inch long and are vicious biters, biting any area of the body that is exposed. These insects prefer to feed during the early morning and evening hours, but may feed for longer periods during windless days and overcast skies. On damp, cloudy days with little air movement I is best to plan to stay indoors to avoid these pests. Should someone complain about something biting them, but cannot see what it is, the chances are very good that the culprit is a biting midge. Also, since midges prefer to fly about in swarms, it is likely that many midges in search of blood meals will bite a host.

The symptoms of bites include pain, plus reddened, itchy and swollen areas around the bite that begins to show up within about 30 minutes after being bitten. These reactions are the result of the anticoagulation components of the injected saliva that keeps the blood from clotting. While the major problem from biting midges are their nuisances and bite reactions, these insects are capable of transmitting bluetongue virus to sheep and cattle in the U.S.

Sand Flies (Family Psychodidae)

Sand fly adults are golden, brownish or grey, about 1/8 long, humped- backed, and have long slender legs. One distinctive feature of sand flies is they hold their wings in a V-shape when at rest. Only the female sand flies have biting mouthparts and suck blood. Sand flies are not strong fliers, so windy conditions tend to make them less likely to bite. While bites from sand flies are much less common than from biting midges, their bites produce irritation and skin –related symptoms. But, the bite of sand flies can transmit the organism that causes sand fly fever, plus cutaneous and visceral leishmaniasis. Fortunately, these are diseases only occasionally reported in the United States.

Black Flies

Black flies are commonly called black gnats, buffalo gnats or turkey flies. While female black flies are blood feeders, males primarily feed on plant nectar. Black flies are 1/5-1/4 inch long, shiny black in color and have a stout body with relatively short legs and antennae.

Black flies are likely to be feeding in swarms, flying around the head and biting in large numbers. Their bites may initially be painless but bleed a great deal. The typical symptoms of black fly bites include itching, burning skin lesions, sometimes fever and numerous blood spots where adult females bite. These symptoms may persist for several days. Common black fly hosts are people, livestock, wild mammals and birds. Black flies are known to fly for long distances to take a blood meal.

There are no known diseases transmitted to humans by black flies in the United States; however, Onchocerciasis, also know as River Blindness, is transmitted by these flies in Africa and other tropical parts of the world.

Prevention of Bites

Using a registered and effective insect skin or clothing repellent helps reduce gnat bites. In addition, wear clothing that covers the skin and if possible avoid areas where biting gnats are actively feeding.