Scotland is about to come under attack from swarms of bloodthirsty predators as forecasters predict that midges will descend in vast numbers this week amid “perfect” conditions of heavy rain and sunny spells.
Any hopes that the cold winter might have killed the midge larvae have been dashed.
“The larvae are well protected underground over the winter and may even have got extra protection from the thick snow,” said Alison Blackwell, who runs the Scottish Midge Forecast website.
The insect may be more resilient in cold weather than its natural predators, bats and birds.
“Warm weather this weekend will result in a big increase in midge numbers next week and if it remains wet one day and sunny the next that can give high numbers throughout the summer,” Dr Blackwell said.
Advertisement
There are peak times for Midges. They emerge from underground larvae in late May or early June and numbers peak at the end of June. Adults then lay eggs that emerge in a second peak at the end of July or August. If the summer stays warm, there may be a third peak in September.
There are five species of biting midges in Scotland but the most bloodthirsty is the Highland midge, Culicoides impunctatus, which leaves its victims with a mass of pinprick bites.
Although it is a tiny insect, with a wingspan of just 1-2mm, it packs quite a punch — although only the females give cause for concern.
“A midge has a set of mouth parts which are like shearing scissors. They cut a hole in your skin and create a pool of blood and then suck from that,” said Dr Blackwell.
The scourge of the Highlands and islands of Scotland, midges have ruined many a holiday. In 1872, Queen Victoria was forced to abandon a picnic in Sutherland and wrote in her diary that she had been “half-devoured” by midges.
Advertisement
The midge is such a problem that costs the Scottish economy an estimated £286 million each year because tourists are put off visiting.
It thrives in western Scotland because it needs a wet climate of more than 120cm (50in) of rainfall each year, humid air and a boggy, acidic ground.
The drier climate of eastern Scotland helps to keep midge numbers down, and several years ago tourism authorities in East Scotland made a virtue of this by advertising that the region suffered fewer numbers of midges.
However, the biting insects are spreading further afield, even into the Lake District and North Wales, and there are concerns that if we continue to have warm, damp summers there will be an overall increase in numbers.
The midge forecasts are made using weather forecasts and special midge traps. They are attracted by body odours, especially the carbon dioxide breathed out by people and animals, and this is used to trap the insects so that their numbers can be counted.
Advertisement
The traps can also be used to keep midge numbers down — a single trap collected 800,000 midges over five days last year.
Other effective preventative measures include wearing long-sleeved clothing and a good insect repellant, including Avon’s Skin So Soft body lotion — reputedly used by the SAS as a mosquito repellent in the jungle.
Although its bite is irritating, it does not pose a serious health hazard. However, its cousin Culicoides obsoletus carries the lethal bluetongue virus which attacks sheep and cattle.
This midge has been spreading further north through Europe and reached the UK in 2007, but has since retreated.