Don't let the midges bug you

Scotland is notorious for its vicious insects but there are plenty of ways to deter them, says Judith Woods

As Southerners grumble about the occasional mosquito bites that are the price to be paid for hot weather, spare a thought for those hardy souls heading to Scotland for the Glorious Twelfth. Blood will most certainly be shed - but it has nothing to do with the grouse.

At this time of year, the hunter invariably becomes the hunted, as millions upon millions of biting midges rise in an ominous swarm through the air and surround their human prey, tiny jaws at the ready.

Tory leader David Cameron and his family will know from sojourns at their holiday home in Jura that swarms of these little fiends can cause havoc - not least because they are highly selective about their victims, singling out particular individuals for their gruesome attentions.

According to Edinburgh University's Centre for Tropical Medicine, midges respond to the combination of chemicals - including lactic acid - present in the sweat of certain people, which they detect via their highly sensitive antennae.

Research is focusing on the development of a repellent that can block receptor sites on midge antennae, but until such a product becomes available, those of us who are vulnerable must find other ways to manage the midges.

When a midge bites, it uses its pinking-shear-like mouthparts to cut a hole in its victim's skin and injects an anticoagulant to stop the blood from clotting so that it can feast on the resulting pool. The anticoagulant induces an immune - or allergic - response which in some people causes the area to swell and itch. The lucky ones experience an irritation that subsides within minutes.

"The proportion of people who suffer very bad reactions is incredibly small," says Alison Blackwell of Edinburgh University, who has spent the past 16 years researching how to combat midges.

"For children, being bitten can be very upsetting, but very often it's the fact the midges tend to swarm around faces and bodies that people find most distressing."

When they've identified a food source, midges emit pheromones to call others to join them - hence the swarming. This means that victims are seldom bitten just once.

Midges adore the warm, damp conditions of high summer and thrive in bogs and wet grassland, with their population peaking between mid-July and September. Warmer temperatures in the past decade have seen their numbers rise in places such as Cornwall and Pembrokeshire, but the Scottish midge still reigns supreme.

There are 37 species of midge in Scotland, but 90 per cent of bites come from one type, Culicoides impunctatus. Scientists estimate that 24 million midge larvae can develop on one hectare - and as the west coast of Scotland covers four million hectares, the numbers involved are mind-boggling.

The good news is that it's only the pregnant females, on the hunt for protein, who bite. They prefer the blood of cattle to humans, but holidaymakers who venture into their habitat become nutritious targets, too.

It is estimated that midges cost the Scottish tourist industry up to £268 million a year in lost revenue, because many avoid visits during midge season. A forestry study carried out in the mid-1980s also suggested that 20 per cent of working days were lost because clouds of biting midges make timber felling and tree planting nigh impossible.

To help humans in their battle not to be bitten, Blackwell has created a midge forecast service at that gives five-day predictions of midge movements in Scotland. She has also helped develop a trap, the Midgeater, which mimics the scent and temperature of a mammal and draws the midges in.

"The problem with insect repellents is that they stop the midges from biting the skin but not from swarming around you," says Blackwell.

"Midges detect people and animals by the carbon dioxide on their breath. The Midgeater gives out carbon dioxide, which is warmed slightly and combined with chemicals, including what is effectively 'essence of cow'. The midges fly into it and are held there until they die."

At £629 for a unit for commercial use and £429 for the domestic-sized cylinder, the Midgeater - to be placed outdoors at the beginning of the midge season - is an expensive way of counteracting the menace, but there's a host of other anti-midge paraphernalia available, too, including anti-midge hat nets, midge body suits and midge netting designed to cover the entrance to tents. Don't be tempted to use mosquito nets, however, as midges are so small that they would get through.

There are any number of traditional remedies that will allegedly ward off minuscule marauders; some people swear by yeast tablets or Marmite, as the insects apparently dislike the scent of vitamin B in the blood. Chewing garlic is another option, as is pinning a sprig of bog-myrtle to your clothes.

Burning citronella will help to deter midges, but those in the know, including the Royal Marines guarding the nuclear base at Faslane on Scotland's west coast, call on an unexpected source for all their midge needs: Avon.

The cosmetic company's Skin So Soft range does more than guarantee velvety-soft upper arms after a bath: it's also a powerful midge-repellent. The Soft & Fresh Dry Oil Body Spray (£2; provides an oily protective layer so effective that the soldiers buy it in bulk.

"Obviously we don't market our product as a midge-repellent, but its reputation has spread by word of mouth," says Lydia Durkan of Avon. "We know that film crews use it a lot when they are up in Scotland and Mel Gibson used it when he was making Braveheart here. We're very pleased that it's proving so popular."

Locals aren't immune to midge attacks, of course, but they tend to be more sanguine about their seasonal plagues. Yes, midges may blight barbecues, they may put something of a dampener on the Scottish summer, but at least they perform one useful function: ensuring the English don't outstay their welcome.