Sydney, Jan 4 : The tiny seed-sized brain of the honey bee is such an evolutionary marvel that it can estimate the exact energy expenditure while foraging for pollen.

"To make honey, bees must gather more nectar from flowers than the energy spent collecting it, so in order to forage efficiently they need to know how much energy each foraging trip costs them," said Andrew Barron, study author and senior lecturer at Macquarie University.

Bees estimate distance visually. Barron set out to determine whether bees also use this visual information to estimate their flight costs.

The results of the study showed the bees were definitely not using distance to estimate cost, but raised another question - how were they doing it?

"The bee brain has an incredibly simple make-up and yet it appears to possess an onboard calorimeter or stop-watch," Barron said.

"Our study showed that bees can separately calculate distance travelled and foraging efficiency and communicate both independently using different elements of their dance language. Such mental agility explains bees' proficiency as nectar harvesters."

Barron said his aim was to work out how the bee brain makes these complex calculations, said a Macquarie release.

"Through their dance behaviour we get a window into bee psychology and perception," he said. "Bees are beautiful little animals with great personalities - and we're only just getting a sense of how smart they really are."

These findings were published in the Proceedings of the Royal Society of London. (IANS)