A “mega second generation” of midges could be about to plague the Scottish Highlands, according to one of the country’s leading midge experts.
Dr Alison Blackwell, head of the Scottish Midge Forecast, has warned that recent weather conditions are likely to conspire to create a massive midge population.
The forecast noted the insects, enabled by a warm spell following a cold spring, hatched within a shorter timeframe than usual, resulting in “a large first hatching with smaller geographical variations”.
Should the current weather remain humid or damp – which meteorologists say is probable – Dr Blackwell believes we should expect a “mega second generation” to start hatching in the next few weeks.
Midge populations last year were hampered by sustained hot and dry conditions for the biting insects. However, the high humidity levels of 2023 may fuel a population explosion.
“Now we’ve got a big starting population, it means that the levels will stay quite high now throughout the summer probably, unless there’s a really dry heatwave,” Dr Blackwell explained.
“At the minute it’s quite humid, which is perfect for them.”
The Highland midge (Culicoides impunctatus) larvae remain in the soil throughout winter before becoming flying adults in spring. A breeding frenzy then initiates a second batch six weeks after the first hatching.
“We would normally expect the first peak of adults in the last week of May, first week of June,” added Dr Blackwell.
“That appears to have been delayed because of the colder weather we had at the beginning and middle of May. The ones emerging now will lay eggs and then in six weeks’ time we will have a second emergence.
“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 damp, I think we’ll have a mega second generation probably because we’ve got so many first generation adults out just now.”
The damp, peat soil of Scotland’s west coast often means greater populations of the creatures.
“It also tends to be a bit milder as well which is better for their activity,” Dr Blackwell said.
“The winters are less cold usually than the east coast so you get a greater survival rate of the overwinter larvae as well.”
As the director of APS Biocontrol in Dundee, which creates the Scottish Midge Forecast, the scientist explained that midge populations were predicted through live data and advanced modelling.
“We have a series of midge traps across Scotland and people collect data for us,” she said.
“We also model populations based on years of population data and weather data so that our forecast is primarily driven by a set of algorithms.”
For the latest data and information on midge populations, visit The Scottish Midge Forecast.