A new study has shown that bumblebees pick up new “trends” in their behavior by watching and learning from other bees, and that one type of behavior can spread quickly through a colony even when another version is discovered.
The research, led by Queen Mary University of London and published today (March 7) in PLOS Biologyprovides strong evidence that social learning drives the spread of bumble bee behavior—in this particular case how they forage for food.
A number of experiments were set up to determine this. The researchers designed a two-option puzzle box that could be opened by either sliding a red tab clockwise or a blue tab counter-clockwise to reveal a reward of 50 percent sucrose solution.
‘Demonstrator’ bees were trained to use either the red or blue flags while ‘observer’ bees looked on. When it was the observers’ turn to tackle the puzzle, they overwhelmingly and repeatedly chose to use the same method they had seen, even after discovering the alternative option. This preference for the taught option was maintained by entire colonies of bees, with an average of 98.6% of box openings made using the learned method.
The importance of social learning for the acquisition of puzzle box solutions was also illustrated through the control group, which lacked a demonstrator. In this group, some bees succeeded in opening the puzzle boxes, but so far did so fewer times than those who benefited from seeing another bee do it first. The average number of boxes opened in a day by the observer bees with a demonstrator was 28 boxes per day, compared to only 1 for the control colony.
In a further experiment, the researchers put both ‘blue’ and ‘red’ protesters into the same populations of bees. In the first population, 97.3% of the 263 cases of box opening by observers on day 12 used the red method. In the second population, observers preferred the blue method over the red method on all but one day. In both cases, this showed how a behavioral trend could arise in a population in the first place – mostly due to experienced bees withdrawing from foraging and new learners emerging, rather than any bees changing their preferred behavior .
A bee opens a puzzle box by pushing against the red tab to turn the lid of the box clockwise. Credit: Bridges AD et al., 2023, PLOS Biology
Similar results from similar experiments have been used in species such as primates and birds to suggest that they, like humans, are capable of culture. If bumble bees are also capable of this, this could potentially explain the evolutionary origins of many of the complex behaviors seen among social insects. It could be possible that what now appears to be instinctive could have been socially learned, at least initially.
Dr. Alice Bridges, the lead author from Queen Mary University of London, said: “Bumble bees – and indeed, invertebrates in general – are not known to show culture-like phenomena in nature. However, in our experiments we saw the spread and maintenance of a behavioral “trend” in groups of bumble bees – similar to what is seen in primates and birds. The behavioral repertoires of social insects like these bumblebees are some of the most intricate on the planet, but most of this is still thought to be instinctive. Our research suggests that social learning may have had a greater influence on the development of this behavior than previously imagined.”
Professor Lars Chittka, Professor of Sensory and Behavioral Ecology at Queen Mary University of London and author of the book ‘The Mind of a Bee’, said: “The fact that bees can see and learn, and then make a habit of that behavior , adding to the ever-growing body of evidence that they are far smarter creatures than many people give them credit for.
“We tend to overlook the ‘alien civilizations’ formed by bees, ants and wasps on our planet – because they are small and their societies and architectural constructions appear to be guided by instinct at first glance. Our research shows however, that new innovations can spread as social media memes through insect colonies, indicating that they can respond to entirely new environmental challenges much faster than evolutionary changes that would take many generations to manifest.”
Reference: “Bumblebees acquire alternative puzzle box solutions via social learning” by Alice D. Bridges, Olga Procenko, Charlotte Lockwood, Yaseen Mohammed, Amelia Kowalewska, 07 March 2023, PLOS Biology.