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Learned behaviour can spread quickly through populations, study finds.

A new study by Queen Mary University of London has shown that bumblebees learn new foraging behaviours by watching other bees. It also revealed that new foraging behaviours can spread quickly through a colony, even after an alternative foraging method has been discovered.

The study set out to investigate social learning in bumblebees and how new foraging behaviours can spread through bumblebee populations. To do this they carried out three experiments, for which the researchers designed a two-option puzzle box that could be opened by either pushing a red tab clockwise, or a blue tab counter-clockwise. Once opened, the box would reward the bumblebee with a 50 per cent sucrose solution.

The first two experiments saw a single trained demonstrator bee enter a population, where it would either show the population how to solve the puzzle by pushing the red tab or the blue tab. There was also a control group that had the opportunity to solve the puzzle without the presence of a demonstrator.

The third experiment added multiple demonstrators into a population to demonstrate both techniques for solving the puzzle.

The results showed that observer bees overwhelmingly and repeatedly chose to solve the puzzle using the same method as the demonstrator they had observed, even when they discovered an alternative method. On average, 98 per cent solved the puzzle using the taught method.

The control group (without a demonstrator) did solve the puzzle, but on fewer occasions than the groups that observed a demonstrator. The average number of boxes opened in a day by the observer bees was 28, compared to one box for the control group.

In the third experiment, the majority of bees in the first population of bees, chose to solve the puzzle using the red method. In the second population, the blue method was the preferred option, demonstrating in both cases how a behavioural trend might emerge in a population.

Researchers suggest that this is mainly due to experienced bees retiring from foraging and new learners coming forward, rather than any bees changing their preferred behaviour.

Lead author Dr Alice Bridges said: “The behavioural repertoires of social insects like these bumblebees are some of the most intricate on the planet, yet most of this is still thought to be instinctive. Our research suggests that social learning may have had a greater influence on the evolution of this behaviour than previously imagined.”

Professor Lars Chittka, co author of the study said: ”The fact that bees can watch and learn, and then make a habit of that behaviour, adds to the ever-growing body of evidence that they are far smarter creatures than a lot of people give them credit for.

“Our research shows, however, that new innovations can spread like social media memes through insect colonies, indicating that they can respond to wholly new environmental challenges much faster than by evolutionary changes, which would take many generations to manifest."