Bumblebees spread behaviour through social learning
Richard Becker / Alamy Stock Photo
Bumblebees can teach each other how to solve a puzzle box, and they prefer the method their sisters teach them rather than those they learn on their own. This adds to evidence that these insects are capable of social learning, and they use it to share trends and sustain cultures over time.
Researchers ran a series of experiments in which 10 colonies of buff-tailed bumblebees (Bombus terrestris) had to solve a puzzle box to access a sugary solution inside. There were two possible solutions – push a red lever clockwise, or push a blue lever anticlockwise. Each colony had a designated demonstrator bee who was privately taught one of the two ways to open the box by a human trainer. Then, demonstrators were reintroduced into their colonies and the entire group had the opportunity, for 3 hours each day over six to 12 days, to crack the code for sweet goodness.
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The bees used the trick they were taught by their colony mates more than 98 per cent of the time, even when more than half of them figured out the other lever worked just as well. “Even when they found the easy alternative, they still flipped back to the demonstrated behaviour,” says Alice Bridges at Queen Mary University of London. “That was really crazy.”
In colonies where no bee was taught by a human how to solve the puzzle, the insects managed to open the box only a handful of times.
These results suggest that behaviour can be spread in groups of bumblebees through social learning and be maintained over time, like cultural trends. “That’s exactly what we mean when we talk of the transmission of culture in animal communities,” says Andrew Whiten at the University of St Andrews in the UK, who wasn’t involved in the work.
These findings do an exceptional job of unveiling cultural learning among insects, says Claudio Tennie at the University of Tübingen in Germany. But this should be thought of as “minimal” culture, he says, because it only tackles two domains of information.
The bees in these experiments passed on information in the “know-what” domain – push the lever – and “know-where” domain – which lever. But they don’t necessarily share more complex information regarding the “know-how”, such as a series of multiple actions to carry out with the lever, says Tennie. “They land and, like a rammbock [a device to smash through walls], they just push through,” he says. “I label these things as minimal culture.”
Even a form of minimal social learning could come in handy as a buffer against global warming or other shared challenges. “Instead of just waiting for less equipped individuals to die from natural selection, and better ones to survive, if you can learn a new behaviour to overcome an issue, then that is really beneficial to you,” says Bridges.
Article amended on 8 March 2023
We changed the photograph to one depicting Bombus terrestris.
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