The Highland biting midge has been known to reduce grown men and women to tears and a wide range of measures have been employed over the years in an attempt to thwart the wee terror. These have met with varying degrees of success, but scientists have yet to come up with the definitive answer and midges still make life a misery for lovers of the great outdoors in the North of Scotland every summer.
It has been estimated that this is costing the Scottish tourist industry about £286 million a year in lost revenue. A recent study found that 49% of tourists surveyed said they would not return to Scotland again at the same time of year because of midges. And 67% of those surveyed said they would warn friends and family to avoid the midge season in Scotland.
Midges are much smaller than mosquitoes, with a wingspan of no more than two to three millimetres, and there are more than 1,000 species worldwide. About 40 of these are found in Scotland with one species, culicoides impunctatus, being best known for biting people.
In Scotland, midges spend the late autumn and winter as larvae, living below the soil surface. They begin to emerge as adults in May and June the following year, encouraged by lengthening days and warmer temperatures. These adults lay eggs that develop relatively quickly to give a second emergence of adult midges in late July and August.
Warm weather in August can result in a third generation of midges, which happens roughly once every three to four years.
There are generally midges around until about the end of September, but the length of the season is entirely dependent on the weather.
Midges thrive in damp, acidic soil. This is one reason that greater numbers are found on the west coast of Scotland, where they prefer the milder winters to the often-Arctic conditions of the East Coast, which often freeze the soil and kill the overwintering larvae.
Both male and female midges sugar-feed on plant nectar, but only females blood-feed, requiring the blood proteins and fats to develop their eggs.
And midges are mainly attracted to potential victims by the carbon dioxide in their breath. They can detect minute changes in the air's carbon-dioxide levels at a distance of 200 metres from the source.
Other chemicals found in our breath and metabolic by-products exuded in our sweat add to the attractiveness of an odour plume. At close range, these chemicals are made even more attractive by the host's warm skin. Midges also love dark colours and moving objects.
Unfortunately, it seems to be a lot easier to attract midges than it is to repel them.
Apart from a variety of anti-midge clothing, or perhaps smoking a pipe, personal repellents are about the best line of defence against biting midges. Personally, I have found Mosi-guard to work well for me. Others swear by Avon Skin-so-Soft.This has not worked for me.
For those who prefer natural products, there are a variety of repellents based on a range of plant oils, including eucalyptus, lemon grass and bog myrtle, with which the Scottish crofters used to stuff their mattresses to keep away midges and other biting beasts.
Some campsites and other tourism operators also use midge killing devices. These use carbon dioxide and an attractant to draw midges to the machine, which then sucks them into a net where they die of dehydration. It is also worth remembering that, if you are staying in a midge infested area and leave the window open at night with a light on, you will end up with a room full of midges.
There are those who believe that taking garlic and yeast tablets keeps midges away, but there is no scientific evidence that these are effective
The terror of the wee biting beast has also given rise to a number of midge myths. These include a tale that the proximity of the biting midge and the wearing of the kilt gave rise to the Highland fling.
It is also said that if you kill one midge, a thousand will come to its funeral.
Facts and photos used on this page provided by Dr Alison Blackwell of APS Ltd, professional insect-management consultancy. Dr Alison Blackwell is an internationally-recognised authority on biting insect biology, particularly biting midges.