SCIENTISTS have discovered how the Scottish biting midge pierces human skin, “like a jigsaw power tool”.
They found that the insect uses its head to gyrate and force its sharp jaws deeper in to the skin.
The tiny insects can then gorge on double their bodyweight in blood before flying off.
The technique is demonstrated in BBC One Scotland documentary “The Secret Life of Midges”, to be broadcast on Monday night.
The hour-long programme is presented by Scottish entomologist Dr James Logan, senior lecturer at the London School of Hygiene and Tropical Medicine, who has studied the midge for ten years.
Scottish entomologist Dr James Logan, senior lecturer at the London School of Hygiene and Tropical Medicine, has studied the midge for ten years.
He said: “No-one has been able to breed midges in a lab, but here we were, able to use cameras and high-powered microscopes that we haven’t ever been able to in the past, and actually see some of the midge behaviour close up in their natural habitat.
“The way they feed I have never seen before. What we saw was their heads gyrating which allows their mouthparts to get deeper in to the skin like a gyrating saw, like a jigsaw.
“That’s why we feel it – they don’t inject an anaesthetic like a mosquito does. Human skin is pretty thick in comparison to a 2mm midge, so the mouthparts are really sharp like two saws sawing and cutting together through the skin.
“They haven’t changed for millions of years for a reason, they are the ultimate blood-seeking machines. They’ve evolved to do their job perfectly.”
The research also shows how midges land and wander over the skin for up to a minute to find an ideal spot in which to sink their mouthparts.
Dr Logan said: “When you are being attacked by midges, the bites are irritating but they come later. It is the annoyance factor of them on your skin.
“They don’t go straight in for the bite. We watched them land, then start wandering across the skin before deciding to bite, and that’s what causes the majority of the horrible irritation.
“They then go in for the bite and spend around two minutes feeding before they fly off.”
The Scottish biting midge has been recorded for thousands of years. Bonnie Prince Charlie was attacked by midges and Queen Victoria had to abandon picnics at Balmoral.
In the 18th century, General Wade is said to have invented the word “hooligans” to describe the midge while building military roads in the Highlands. He misheard the Gaelic for midge - meanbh chuileag. Dr Logan said: “We are all affected by the midge – even royalty.”
Midges weigh just one 2,000th of a gram and 500,000 can emerge from a two square metre piece of suitably peaty land. Their wings beat 1000 times per second – the fastest in the animal kingdom.