Swarms of flying ants have descended on Northern Ireland parks and gardens as they hunt for mates.

Sightings of large numbers of airborne common black garden ants (Lasius niger) were reported as temperatures rose over the last days, although experts say their prevalence depends on localised weather conditions.

One householder in Greenisland described his surprise at discovering the winged ants had entered his house.

“We had left the windows and conservatory door open and we came down to find scores of these ants all over the floor,” he said. “We were quite surprised that they had got in and we were wondering if we had a nest somewhere, but it turned out they had flown in.”

Further afield there were reports on one internet discussion board of people fleeing Bushy Park in south Dublin as the flying ants invaded.

Dr Rob Paxton, of Queen’s University Belfast, said the ants grow wings and take to the air every year at mating season but some years they may be less successful and go generally unnoticed. And he had some good news — the swarm is likely to be fairly short-lived.

“They have perennial colonies underground which can live for 5, 10, 20 years. Each year they generate lots of workers and then generate new males and queens and they meet up in the sky in a swarm,” he said.

“The males are all gathering and the females fly in and they mate. Northern Ireland and the Republic don’t have very many ants compared to warmer climates.

“They are reasonably noticeable when they swarm because people don’t usually see them because they live underground. They send them out over a few days only — it’s not a extended period.”