Bee's knees? Not if they're tired

Just like tired and stressed humans, busy bees that get too little rest start to make mistakes, scientists have found.

Worker bees have the important job of letting their hive-mates know where to find food.

They pass on the information by performing a "waggle dance" containing coded directions to nectar-rich flowers. But when the insects were deprived of sleep, their dances became sloppier and less precise than those of rested bees.

The research, by scientists based at the University of Austin, in the capital of Texas, involved disturbing sleeping bees with a magnetic device that was aptly named the "insominator".

As the magnet was waved over bees fitted with small metallic backpacks, it caused them to be jostled around and woken up.

After a sleepless night, the behaviour of the bleary-eyed insects was compared with that of the naturally rested bees.