Even midnight sun won’t convince bees to work nights

LONDON - Bees observe a strict working day, even in conditions of 24-hour sunlight, research shows.

Researchers tagged worker bumblebees with a radio identifier, similar to an Oyster Card, which was used to monitor their movements during the constant light of the Arctic summer.

Ralph Stelzer and Lars Chittka from Queen Mary University of London, Britain, carried out the study in Northern Finland.

“Constant daylight would seem to provide a unique opportunity for bumblebee foragers to maximise intake, and therefore, colony growth, by remaining active during the entire 24-hour period,” Stelzer said.

“We found that bees do not naturally take advantage of this opportunity, suggesting that there is some benefit to an ‘overnight’ break,” Stelzer added.

The researchers studied both native bees and a group of bee colonies they imported into the Arctic.

Both species worked a day shift, with maximum activity around midday, and retired to their nests well before midnight, a Queen Mary release said.

Stelzer and Chittka speculate that the bees must have some way of telling the time in the absence of day/night cues, suggesting that the insects may be sensitive to light intensity and quality or changes in temperature.

The findings were published in BMC Biology.