BRISBANE, Australia, Feb. 1 (UPI) -- Bees can navigate using the sun even on cloudy days using clues from polarized light to determine the hidden sun's position, Australian researchers say.
Mandyam Srinivasan of the University of Queensland in Brisbane, Australia, says that because sunlight passing through the atmosphere is polarized in a pattern that reveals the location of the sun, it has long been suspected bees use special photoreceptors in their eyes to navigate on cloudy days, NewsScientist.com reported Tuesday.
Now, Srinivasas says, he has "the ultimate proof" that theory is correct.
He and his team created a simple "maze" of four tunnels and flooded two of the corridors with light polarized parallel to the length of the corridor, the other two with light polarized perpendicularly to the corridor.
They then trained about 40 bees to enter the maze through one corridor and exit via a second that had a sugar reward at its end.
When the sugar was removed, the bees continued to use the same exit. But when the polarized light patterns were switched, the bees began using a different exit -- one that now was indicated by the polarized light patter than had previously led to the sugar.
And each time the researchers switched polarization patterns, the bee would head to a different exit, whichever one was flooded with the "sugar" light pattern even though the sugar had been taken away.
The bees were reading and staying "faithful" to the polarization patterns they associated with the sugar reward, Srinivasan says, proving they were utilizing polarized light to navigate.