The oval-shaped brain of a honeybee is roughly the size of a single sesame seed. It contains fewer than 1 million neurons, while the human brain contains 100 billion.
Many animals display some degree of quantitative understanding as they forage and fight, hoard and hide and find their way back home. Counting, for instance, is pervasive.
But bees can do something more, according to a paper published in the peer-reviewed Science Advances journal. They can add and subtract, placing one of the world’s leading pollinators in the venerable company of monkeys, parrots and, yes, spiders — the cognitive A-list of the animal kingdom.
The findings contribute to a growing body of evidence that the brains of insects are more powerful than once thought — capable not just of a vague numerical sense but of the sort of learning and complex memory tasks that make arithmetic possible.
“A small biological processing system can perform quite complex things,” said Scarlett Howard, lead author and a postdoctoral fellow at the French National Center for Scientific Research.
The small neural network employed by bees, she said, points to a possible alternative to high-energy computing, suggesting that artificial intelligence should seek to model natural systems “that have evolved in complex and challenging environments.”
The research builds on the discovery of the same researchers last year that bees understand nothing — that is, the concept of nothing.
In the new study, researchers devised a Y-shaped maze to train 14 bees to add and subtract. Though each bee appeared to learn differently, the population showed signs of mastery somewhere between the 40th and 70th test, Howard said. They appeared not to master one command better than the other, though other species have shown signs of favoring addition, she said.
It comes as bees’ numbers dwindle amid threats from pests and pathogens. U.S. beekeepers lost 40 percent of their managed colonies between spring 2017 and spring 2018, in line with a broader decline of invertebrate populations linked to climate change.
The discovery holds applications beyond honeybees alone. “A honeybee brain contains less than 1 million neurons, so evidence that a bee can learn to use a mathematical operator is very important for our understanding of how big brains, like ours, may have plausibly evolved the capacity for the incredible mathematical achievements that underpins our modern society,” said Adrian Dyer of the Royal Melbourne Institute of Technology.