Declan Coney, a former eel fisher, knew there was something wrong when the famed swarms of Lough Neagh flies failed to materialise. In past years, they would appear around the Northern Irish lake in thick plumes and “wisps” – sometimes prompting mistaken alarm of a fire incident, Lough Shore residents say.

Clothes left out on a washing line “would be covered in them”, Coney says. So would any windshield on a vehicle travelling around the lough’s 90-mile shoreline. Conservationists marvelled at their courtship dances, hovering above treetops.

Last spring the flies never arrived. “This is the first year ever that, if you walked up to the Cross of Ardboe or the area around there, you’d find there’s no flies,” Coney says.