Midge numbers well down in 2023 due to hot summer
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This year's Scotland's midge hatch was among the lowest for the biting beastie, it was revealed this week.
The second emergence was virtually "non-existent" only compensated by high numbers in the first hatch.
July was so hot and dry, it was the worst possible weather for midges.
The Scottish Midge Forecast said the insects hatched within a shorter timeframe in June because of a cold spring followed by a warm spell.
But top midge expert Dr Alison Blackwell - whose company runs the forecast - said while this resulted in a large first hatching with smaller geographical variations, the subsequent dry spell saw a record low second hatch, and that is the one that tends to feed on people more.
"About 7C is the cut-off point for a midge to fly. Midges do not like it hot and dry," she said.
"The numbers fall quickly in hot spells. They only have a 2mm wingspan so they become dehydrated quickly.
"So the second hatch struggled with the heat and was the lowest we have recorded. In fact, it was virtually non-existent. Only the first hatch produced good numbers."
The tiny biting insects thrive in wet and warm conditions and usually have two hatchings during the Scottish summer.
Last year dry conditions also made life difficult for the midges.
Dr Blackwell added:"How big that second peak is, depends on the first generation of midges and how many batches of eggs have been lain.
"If it becomes dry, they just don't like it.
"The female will lay around 100 eggs in her first batch, which will live off fat reserves from her stomach. But she will then lay second or even third batches of 30-40 eggs every few days later and they will need a blood meal. That's where we come in! But only the female bites."
Scotland has more than 35 species of biting midges, but one dubbed the Highland midge is the most ferocious, according to the forecast team.
The Scottish Midge Forecast is run by Dundee-based APS Biocontrol Ltd, which also makes an insect repellent, Smidge.
The Scottish tourism industry is estimated to lose about £286 million-a -year because of the voracious and swarming insects - and that is based on the traditional five-month long midge season.
A previous study also found that many tourists said they would not return to Scotland at the same time of year because of the biting midges.
Dr Blackwell and her team previously calculated the total number of midges in the Highlands and Islands for the first time.
The number of midges seeking a "blood meal" over the summer was put at around around 21 billion.
The larvae of Culicoides impunctatus – the scientific name for the Highland biting midge – overwinter in the soil and usually begin to emerge as adults the following year. These adults then lay eggs that develop relatively quickly to give a second emergence of adult midges in July.
Two million midges weigh just a kilo - and one square metre of land will contain about 500,000 of the insects.
