The bee enthusiasts, based around Red Hook, Brooklyn, were left confused after inspecting their hives to find a thick, scarlet substance that they compared to cough syrup.

One, who had the substance tested, found it contained Red Dye Number 40, a food colouring, which is also found in maraschino cherry juice.

It is thought that local bees enjoyed visits to the vats at the nearby Dell's Maraschino Cherries Company before returning to their hives.

One of the keepers, Cerise Mayo – whose name translates to "Cherry" in French – told The New York Times: "I didn't want to believe it. I thought maybe it was coming from some kind of weird tree."

David Selig, another whose hives were affected, said of his bees: "When the sun is a bit down, they glow red in the evenings. They were slightly fluorescent." The owners of the company have hired Andrew Coté, the head of the New York City Beekeepers Association, to rid their factory of the insects.

"Bees will forage from any sweet liquid in their flight path for up to three miles," Mr Coté told the newspaper.