HE was forced to flee after just three days of his holiday. The blame for it has been scattered around Ian Blackford, his wife, a freelance photographer, the red tops, a rogue police officer or perhaps even a disgruntled farmer when he discovered an unauthorised yurt on his land.

It certainly wasn’t urgent affairs of state which saw Boris Johnson pack his tent (or perhaps that was his bidie-in Carrie Symonds?) and scuttle back to London with his armed close protection officers thankful, no doubt, that they longer had to bunk up under canvas.

But now the truth can be revealed by this newspaper. It was the Highland midge which sent him home to think again, about ever holidaying in Scotland.

The beastie has form. In the summer of 1872 Queen Victoria paid a visit to the Duke of Sutherland at his pile, Dunrobin Castle on the Dornoch Firth. It was a balmy day, a day that seemed ideal for a picnic. Vicky’s diary records what happened. "We stopped to take our tea and coffee but were half devoured by midges." They fled for the damp pleasures of the castle.

A century or so before, Bonnie Prince Charlie suffered a similar fate. Bad enough that he had just been hosed at Culloden and was on the run, but he wasn’t just pursued by the Duke of Cumberland and his redcoats, but by vicious swarms of midges. His aristocratic pins were so badly bitten that he “looked as if he was covered with ulcers” according to a contemporary account.

The wee critter is at least democratic and undiscriminating, it bites not just royalty and high head yins but the hoi polloi, indeed any warm blooded beast it can get its teeth into, but the assault is only carried out by the female, the placid male is happy to suck petals.

And once the female strikes, in a sort of midge social media frenzy, thousands of others swarm to the site to get in on the feast. The first bug emits pheromones and all the others pick up on it and pile in. Kill one midge and all her sisters come to the funeral.

The females are born with enough fat reserves to produce one batch of eggs, but after that they need blood to produce more pests. Apparently only one-in-10 is successful in finding a source, so just think how much worse it could be.

There are more than 150 species of midge, most of which feed on other insects, more than 30 biters in Scotland but only one, the dreaded culicoides impunctatus, the Highland midge, does so habitually and with venom. A swarm can inflict 3000 bites in an hour, in that same time 40,000 can land on an unprotected arm, should you be foolish enough to go for a dander in a short-sleeved shirt or blouse.

Some brave, if utterly doolally, people have taken the one-minute midge challenge (you can see the results on YouTube) including the naked, full-body version but should you be tempted, make sure there’s lochan nearby to plunge into afterwards. Better still, have yourself sectioned.

There a story, no doubt apocryphal, that a gravedigger on Rum in times past did something to offend the locals, perhaps burying a body upright?, and in punishment he was stripped naked, tied to a post and left at the mercy of the midges. It took him some time to die, and goodness knows what his corpse looked like.

Another tale, which carries a shred of authenticity, is that the Highland Clearances were responsible for the massive increase in their numbers. The imported Cheviot sheep chomped all the bushes and hedges, where birds, their natural predators nested, and bingo, mair midges, fewer sparrows.

Perhaps the same thing happened in Australia when livestock was introduced and flies and mosquitoes prospered, hence the Aussie preventative solution, the wide-brimmed hat with the dangling corks.

This would have little effect on our little pest. It may only be about 2mm long and slightly less across with its wings extended but its jaws are razor sharp. Ms Midge finds a human target and feasts on the blood like a microscopic vampire, also injecting chemicals into the wound to stop the blood clotting. She can feed there for up to four minutes, while sending out the alert to the others.

In response to a bite, the human immune system kicks in, pumping histamine and white blood cells into the wound, causing swelling of the skin and that infernal itch we’ve all experienced. The normal way to treat a bite is to ignore it, but if there’s an anti-histamine cream around it may help. Home remedies include crushed ice, aloe vera, honey and porridge. Or you could combine the last two to double the effect, and spoon up any residue.

Oil of citronella is supposed to deter them, also dill, fennel and thyme, although covering yourself in dried, mixed supermarket herbs won’t, and there are various sprays said to do the job, but more of that later.

There’s a wonderful chap at the Glasgow Science Centre called Derek who, as if auditioning for Blue Peter which you can watch online, came up with his patented midge eater, which involves plastic bottles, scissors, sugar, water and yeast. Oh, an extremely smelly sock. You leave the contraption out and the midges will apparently swarm to it on a death mission. Aye, right Derek.

It’s estimated that midges, or the threat of them, costs the Scottish tourism industry about £300million a year, so this article should add a nought or two. One-in-five working days in forestry are, apparently, lost because of them, although as the industry employs less than 20,000 people, and the bulk are in processing, I’m not sure the loss is so grievous.

They first emerge in May and June, after mild and wet winters, although extremely cold ones they tolerate too, they’re most plentiful and pernicious in low light, at dawn and dusk, they like mildly acidic habitats, peaty soil, rushes and bracken, where of course you can also double up on Lyme disease.

A rough rule is that they thrive where there is at least 1250mm (50 inches) of rain a year, which just about applies to the whole map, and they are rare above 700 metres. They’re attracted by the CO2 we exhale (that’s at the heart of Derek’s device), they prefer dark clothes to white, and don’t get out and about so much in dry heat and winds over 6mph.

There’s another breeding burst due in September so if you’re thinking of a late summer Highland staycation best to make it at altitude and pray for wind, but if not invest in oilskins and a midge net headpiece. Or, if you are a green exemplar, the eco-friendly midge hood, hand knitted from recycled Harris wool, possibly from Grandpa’s old jaiket? Who could resist this organic midgie resister?

There are various sprays on the market claiming to repel the pest, although I’ve never found them entirely successful. Although there’s one brand, called Mosi-Guard Natural, which has an unexpected bonus. It, and other brands, contains citriodiol, (not the common DEET), which is made from the leaves and twigs of the eucalyptus citriodora tree and Britain’s armed forces have been issued with cans of the repellent.

I don’t know what it does to midges but scientists at the Defence Science and Technology Laboratory have discovered that citriodiol can kill the strain of coronavirus that causes Covid-19. I expect that when Donald Trump gets to hear about it he’ll be ditching hydroxychloroquine and bleach for a daily swallie of it.

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