Innovative insects: Bumblebees master a mental ability that was previously only known from humans, mammals or birds: They use objects in new ways to solve a problem. In the experiment, the bumblebees rolled a ball under a nectar source to use it as a platform – without having learned or trained beforehand. This is the first evidence of such spontaneous problem solving in an insect, as biologists report in Science.
Crows, cockatoos and great apes are known to use tools and to use them to solve problems if they have not explicitly learned this before. A classic example of such spontaneous problem solving is chimpanzees who stack boxes lying around to reach a high-hanging banana.
“Such problem solving using new approaches and without prior training is considered a core feature of cognitive flexibility,” explain Akshaye Bhambore from the University of Oulu in Finland and his colleagues. However, so far this ability has only been demonstrated in vertebrates with large brains.
Bumblebees in the test arena
But what about insects? After all, social species such as bees, ants and bumblebees demonstrate some astonishing mental achievements: they find their way back to the nest or to nectar-rich feeding sites unerringly, communicate in complex ways and, in the case of honey bees, can even count. “We therefore investigated whether bumblebees (Bombus terrestris) also have the ability to spontaneously solve problems,” report Bhambore and his team.
For their experiment, the biologists placed an artificial flower with a sugar solution on the ceiling of a test arena in such a way that the bumblebees could neither land on it nor float in the air next to it. There was also a Styrofoam ball in the test arena that could be rolled into a small cavity under the food source. This made it a platform from which the bumblebees could reach the flowers.
Innovative solution
“This is essentially an insect version of the classic ‘box and banana’ problem,” says senior author Olli Loukola from the University of Oulu. “The animal must recognize that an object can be repositioned and then used as a tool to achieve an otherwise unattainable goal.” The bumblebees had only learned in advance that the artificial flower contained a tasty reward and that the ball was a movable, harmless object. But the wild bees had never been trained to roll the ball.
Would the bumblebees come up with the solution on their own? In fact, the bumblebees turned out to be amazingly innovative: three quarters of them solved the problem: They rolled the ball under the flower and used it as a platform from which to drink the sugar solution. “One moment the animal was seemingly aimlessly exploring the environment and the next it carried out a highly efficient sequence of actions that led directly to the solution,” reports co-author Ece Nur Akmeşe from the University of Helsinki. “Watching the bumblebees was really fascinating.”
Successful even under difficult conditions
“What makes this behavior particularly remarkable is the fact that the bees had never been trained to do it. This presented a completely new challenge,” emphasizes Bhambore. To make sure that the bumblebees didn’t just come to their solution by chance or guided by visual stimuli, the team carried out further test runs under difficult conditions. In these, the flower was not visible to the bumblebees while they moved the ball. Even under these conditions, the bumblebees solved the task.
“Another important aspect is that our bees were completely inexperienced,” explains Loukola. “In many previous studies, the animals already had extensive experience with objects, test environments or other problem-solving tasks. In our case, the bumblebees lacked any previous experience with this type of solution strategy.”
Highly developed abilities despite a tiny brain
The experiment thus proves that bumblebees also have the ability to spontaneously solve problems – they convert objects into tools if this helps them. “This is the first evidence of this type of spontaneous problem solving in an insect,” says Loukola. At the same time, this confirms that bees have surprisingly highly developed cognitive abilities despite their comparatively tiny brains.
According to the researchers, their results challenge the long-standing assumption that spontaneous problem solving is limited to humans and other large-brained vertebrates. However, this does not mean that the insects have human-like thinking skills or consciousness: “We do not claim that bees think like humans,” emphasizes Loukola. “But our results show that miniature brains can generate flexible solutions to novel problems in ways that we are only beginning to understand.”
Source: Akshaye Bhambore (University of Oulu, Finland) et al., Science, 2026; doi: 10.1126/science.ady1618