Oct. 11 (UPI) -- Bees can count and understand the concept of zero. But their math skills have limits.
Previously, scientists thought bees could only count to four, but new research suggests bees can understand quantities as great as five, provided they're trained with rewards and punishments.
Tests suggest fish are also thwarted by arithmetic thresholds. But it's not just small-brained animals. Human brains are similarly limited. Estimating quantities up to four is effortless for most people, but estimating larger quantities takes more concentration.
Until now, scientists thought bees were incapable of the focus necessary to comprehend larger numbers. However, the latest research showed that when bees are properly trained, they can process quantities as large as five.
For the study, scientists at RMIT University in Australia taught honeybees to associate specific symbols with specific numbers -- much the way humans use numerals to represent different quantities -- and to distinguish between lesser and greater values. The researchers reinforced the associations with a sugary solution, while wrong answers earned a bitter solution.
For half the test bees, scientists only rewarded correct answers. Incorrect selections earned no punishment. The other half of the test group received both rewards and punishments.
Each bee was made to fly to the end of a Y-shaped maze to make their selection and fly back to their hive to share their sugary treat.
Bees that were only rewarded failed to distinguish between four and greater values, but bees that were rewarded and punished were able to distinguish between four and larger quantities. The properly trained bees even learned that five is greater than four.
"Thus, bees' ability to learn higher number discrimination depends not just on their innate abilities, but also on the risks and rewards on offer for doing so," researchers wrote in The Conversation.
Scientists published the results of their tests this week in the Journal of Experimental Biology.