It nevers rains but it pours – and bites.
A bumper crop of midges is expected to emerge at the start of this summer following a mild, wet winter.
The larvae of Culicoides impunctatus – the scientific name for the Highland biting midge – overwinter in the soil and very cold temperatures can affect their survival rate.
They begin to emerge as adults in May and June the following year, encouraged by lengthening days and warmer temperatures.
These adults then lay eggs that develop relatively quickly to give a second emergence of adult midges in late July and August.
A third hatch can occur in September if the second half of the summer is particularly warm.
Alison Blackwell, who is the world’s leading expert on midges, said conditions during the past winter had been perfect for the voracious insects.
She said: “The mild, wet winter will have maximised the overwintering population so, if we get a damp, warm spring, we should get a big first emergence this year.
“We normally get our biggest peak the first week of June as long as the weather warms up during May.
“Last year, when the weather was awful in May, we had a two to three-week delay in the season kicking off.”
Ms Blackwell is director of Dundee-based Advanced Pest Solutions, which runs the Scottish Midge Forecast.
She said it was impossible to say which areas would be worst affected by midges this year as it depended on the weather, but there was usually a hotspot covering the Oban, Glencoe and Fort William areas.
Ms Blackwell said: “Sometimes Skye has a really midgey summer and sometimes it doesn’t. And the further north you go, the more it depends on the weather.”
She added that last year they had about 120 people with cheap traps taking part in their midge watch project across Scotland.
The volunteers were trapped midges, took pictures of their catches and uploaded them to Ms Blackwell’s company’s website so they could be analysed.
“This enabled us to gather a lot more information on localised midge populations and we will be doing that again this year,” said the midge expert.
The midge forecast, which provides advice for hikers and others taking part in outdoor pursuits based on the weather forecast and catches from the traps, is due to start at the beginning of May.