Biting midges are in the news because they spread the Shamonda virus, which this year reached European farms — and, for the first time, a person in France. Read our Shamonda explainer → Here's what makes these tiny insects such a big deal.

They're smaller than a pinhead

Many biting midges (genus Culicoides) are under 1 mm long, and most pest species are under about 3 mm. Scotland's Highland midge has a wingspan of about 1.4 mm and weighs about half a microgram. That's why Americans call them "no-see-ums".

There are about 1,400 kinds

Culicoides is the biggest group of biting midges, with more than 1,400 described species, found on every continent except Antarctica.

Only the females bite — to make eggs

Both males and females drink plant nectar for energy. Only females take blood, because they need its protein to produce eggs — one female of a Florida species lays 50–110 eggs after a single blood meal.

They cut you rather than stab you

A mosquito pierces skin with a needle-like mouth. A midge instead slices the skin with tiny teeth, its saliva stops the blood clotting, and it laps up the little pool of blood — which takes about two to five minutes.

They follow your breath

Female midges find us by the carbon dioxide we breathe out and chemicals on our skin. They bite most at dawn and dusk — and on calm, cloudy days, at midday too.

Mud is their nursery

Midges lay their eggs on wet mud; the eggs die if they dry out. Their larvae live in salt marshes and mangroves, muddy ground on farms and, in Scotland, boggy peat.

One Scottish species does almost all the biting

Scotland has 37 kinds of biting midge, but one — Culicoides impunctatus, the Highland midge — is behind up to 90% of bites on people. Good breeding ground can hold up to 24 million larvae per hectare.

Scotland has a midge forecast

Midges are such a nuisance that Scotland has a Midge Forecast, using traps and small weather stations to predict how bad they'll be. One midge researcher has estimated they cost Scottish tourism about £286 million a year.

They spread serious diseases in farm animals

Biting midges carry bluetongue (in sheep and cattle), African horse sickness, which kills most infected horses, Schmallenberg virus (found in Germany in 2011) and, since summer 2026, the Shamonda virus in European cattle.

One midge spreads a human virus

The US CDC says Oropouche virus spreads to people mainly through the bites of the midge Culicoides paraensis, in South and Central America and the Caribbean. In 2024, the Americas reported more than 16,000 confirmed cases.

They hitchhike on the wind

Infected midges can be blown hundreds of kilometres across the sea in a single night. That's how bluetongue reached Britain from mainland Europe — and UK scientists use wind models to predict new arrivals.

They live for just a few weeks — but are hard to stop

Adult midges live roughly 10 to 30 days, shorter in warm weather. But new ones keep hatching from huge areas of wet ground, so spraying insecticide works poorly. What does help: DEET or PMD repellents (about 98% protection after 8 hours in a Scottish trial) and fine mesh screens — ordinary window screens let them straight through.

Myth or fact? Test yourself

All midges bite.

A light breeze stops Scottish midges from flying.

You can catch bluetongue from eating lamb or drinking milk.

Ordinary window screens keep no-see-ums out.

Some people really are less attractive to midges.

Sources: University of Florida IFAS (no-see-um factsheet); Frontiers in Veterinary Science (2024); Highland midge factsheet (Scottish Outdoor Access Code); STV; WOAH; Pirbright Institute; Germany's FLI; CDC; PAHO; Parasites & Vectors; University of Arizona; Virginia Tech.

Have midges ever ruined a day out for you? React below, and share this with a friend heading to the Scottish Highlands.