Bumblebees can teach each other how to score "goals" with a tiny ball, displaying a learning ability never before seen in insects, a study has shown.
The bees surprised scientists by working out how to use a novel tool to obtain a food reward simply by watching their neighbours.
In the experiment, the bees were placed on a platform and had to roll a yellow ball to a specific location - or "goal" - in order to obtain a sugar solution.
They were given two types of training, either watching a previously trained bee "score", or being shown the ball that appeared to move on its own with help of an unseen magnet.
Insects that observed the success of other bees were better at learning the task than those given the "ghost" demonstration.
Project leader Professor Lars Chittka, from Queen Mary, University of London's School of Biological and Chemical Sciences, said: "Our study puts the final nail in the coffin of the idea that small brains constrain insects to have limited behavioural flexibility and only simple learning abilities."
The bees did not simply copy exactly what they saw, but figured out their own way to get the ball to the right destination.
"This shows an impressive amount of cognitive flexibility, especially for an insect," said Dr Olli Loukola, another member of the Queen Mary team.
During the tests, the bees had to roll a ball from the edge of the platform to the centre.
Initially, "demonstrator" bees were trained by watching a plastic bee pushing the ball to the goal.
They then moved the ball in front of other bees undergoing training, who quickly learned the same trick.
But in later trials "observer" bees faced with a choice of three balls made a beeline for the one closest to the goal, rather than the one at the platform edge.
In yet another test they had to move a differently coloured ball to earn the reward.
Dr Loukola said: "It may be that bumblebees, along with many other animals, have the cognitive capabilities to solve such complex tasks, but will only do so if environmental pressures are applied to necessitate such behaviours."
The research is described in the latest issue of the journal Science.