Swarms of flying ants have been seen across Scotland taking part in a spectacular annual mating ritual.
The clouds of large flying insects on Tuesday left some people alarmed - but experts said there was no need to be afraid as the insects would not bite.
Large female ants pick one day a year to mate by sensing temperature, humidity and day length.
The males then die while the females shed their wings before making a new colony.
Dr Graham Rotheray, curator of insects at the National Museums of Scotland, said people would not be bitten by the insects.
He told the BBC Scotland news website: "It may be very alarming for people to be surrounded by these large ants in the air but it is a perfectly normal and natural phenomenon, which happens annually.
"People should allow it to happen and watch it rather than trying to kill or swipe them out of the way.
"It is a spectacle to see the queens fly high into the air before mating with the much smaller males.
"Ants are part of the hymenoptera family, which includes bees and wasps. They can therefore look like wasps to people but the large females don't bite so people can be calm when they see them.
"What is marvellous is that they all can co-ordinate leaving their nests on the same day once a year."
Dr Sarah Reece, of Edinburgh University's evolutionary biology department, said: "The evolutionary aim of the ant is to spread to form new colonies.
"The queens fly into the air to mate and do not bite. It is the soldier ants guarding the colony on the ground that bite.
"It was very humid in Edinburgh on Tuesday and this is what has caused them to come out and mate.
"They monitor the day length, humidity and temperature to pick just one day a year to mate.
"They are responding to the environment and should not cause alarm to people as they don't bite or transmit disease.
"It is an amazing mating ritual."
Barry Cameron, 35, from North Queensferry, said he was out jogging on Tuesday when he was hit by clouds of the flying ants.
He said: "I was in Inverkeithing when I noticed swarms of insects, which kept whacking into my face.
"It seemed really unusual and my T-shirt was covered in black flies when I got home, I was really wondering what they were."
A 37-year-old woman, who wished to remain anonymous, said she was unable to get out of her car in Granton in Edinburgh because there were so many ants covering her vehicle and flying around the doors.
She said: "I felt terrified. It was really horrible. When I finally got out of the car I was covered in them and I felt they were going to bite me."