A cloud of ants flying over the UK was so dense it could be seen in satellite images from space, forecasters have said.
The swarm of insects darkened the skies above southern England yesterday and were captured on the Met Office's radar.
An interactive map shared by the national forecaster showed the "insect clutter" stretching more than 350 miles – all the way from Penzance in Cornwall to Sturry in Kent.
The Met Office tweeted about the phenomenon on Wednesday afternoon, writing: "The latest view from space shows that our radar is picking up something that isn't precipitation along the south coast…”
The mystery patch was a cloud of flying ants it went on to reveal, writing: "We know this to be insect clutter based on inspection of raw reflectivity.
A Met Office spokesperson later told the Standard how they were able to recognise the phenomenon.
— Met Office (@metoffice)July 17, 2019
“Our radars are sophisticated enough to differentiate between rain and snow, and they can also gauge light reflections to spot when insects are causing these ‘clutters’,” he explained.
BBC weather presenter Simon King said forecasters could tell it was not rainfall showing up on their systems because “it has that eerie look to it”.
“It doesn't quite match what rainfall looks like,” he said.
The phenomenon was spotted between 8am and 11am yesterday, moving across Hampshire, West Sussex, Kent and Dorset.
— Simon King (@SimonOKing)July 17, 2019
Experts said the bugs’ mass movement was caused by potential new female queens and male ants embarking on a mating flight.
As the queen sets off, she emits pheromones that attract the males.
But when they follow her she flees, meaning only the strongest are able to keep up and mate with her.
Mr King said it was the biggest swarm of insects he had seen in the UK, and was a more common sight in parts of the United States.
He added: "For it to actually to appear on the radar imagery, that's something certainly incredible, and I just feel sorry for all the people who have to experience those flying ants."