Ball-rolling bumblebees capable of reasoning

23 February 2017



Bumblebees have been trained to roll a ball into a “goal” in reward for sugar-water. They were able to pick up the behaviour from seeing the ball roll in on its own, but were found to learn even more efficiently when watching other bees perform the same task and in some cases, even improved upon the solution demonstrated to them.

This complex learning behaviour could indicate that bees and other small-brained animals are able to pick up new tasks provided there’s sufficient pressure on them to do so. Researchers at Queen Mary’s University London designed a series of different demonstrations to work out exactly how the bees were best adapted to learning.

The bees were trained in three separate ways to determine the social aspects of their learning behaviour. One group simply found the ball already in the centre of an “arena” with the sugar-water already available, the second observed the ball moving on its own (pulled by a magnet out of view of the bees) and the third watched “dummy-bees” (small plastic bee replicas attached by a transparent rod) perform the operation and the sugar-water appearing.

When it came to completing the task themselves, the rate of success was higher for those bees that had a demonstration compared to those that had no demonstration with a moving ball. However, the highest success rate with the quickest average completion time came from the third group, those that had the task demonstrated to them by a real or “dummy” bee.

Not only did the bees pick up the task better from “social learning” but they were even able to notice a smarter approach to the problem.

In the circular arena where the bees performed the task, there were three balls available for the bees to push into the hole, all at different distances in a “Y” shaped configuration from the centre. The bees were only ever “taught” using the furthest ball from the centre, coloured bright yellow. Instinctively however, the bees would always push the ball already closest to the goal into the centre to obtain the reward, opting for the most efficient route. Even when the “easy” ball closest to the centre was coloured in black, different to the colour of the ball the bees had been trained on, they still elected to push that ball into the goal to obtain the reward.

Remarkably, the bees didn’t simply copy what they had been taught like tiny machines. Instead they applied a rudimentary step in reasoning to save themselves some effort in accomplishing a goal.

One of the lead authors on the study Clint Perry, thinks this is a step forward for understanding cognition and behavioural flexibility in the animal kingdom.

“Most of us, when we see bees or insects of any type, we look at them as genetically pre-programmed, unthinking machines. But there’s no real behaviour that’s been shown to require a large brain; decades of research has shown that bees and other insects can learn, solve complex tasks and navigate complex environments. The reason we’re studying this in insects is the combination of bees having cognitive abilities as well as small, accessible brains. We can record from and study individual neurons within the bee brain whilst at the same time looking at the entire thing. In larger animals, there are so many neurons it’s hard to get at with the tools available today.”

So neuroscience on tiny scales could open a window on understanding larger animals, though the bees' behaviour is fascinating in its own right. Despite this, while the best of the them might be adept at rolling balls around for sugar-water, it's unlikely we'll be convincing them to play 11-a-side for the cham-bee-ion's league any time soon. 


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