Bumblebees may be smarter than we give them credit for, with a new study showing the fuzzy insects have the cognitive plasticity required to overcome novel challenges.
Researchers from Finland's University of Oulu, University of Helsinki and University of Turku set out to see whether bumblebees (Bombus terrestris) could solve a novel object-manipulation task independent of cues from other individuals or without demonstrating spontaneous problem-solving behavior.
In the task, each bee saw that a blue artificial flower meant a reward. But during the test, the flower was moved out of reach, requiring the bee to innovate to reach the sweet prize. Essentially, they needed to manipulate a small ball beneath the flower to access the area where the reward was located.
This may not seem like a big task, but it's a behavioral sequence scientists had never seen in bees.
“This is essentially an insect version of the classic ‘box-and-banana’ problem,” says senior author Olli Loukola, Docent at the University of Oulu. “The animal must realize that an object can be repositioned and then used as a tool to reach an otherwise inaccessible goal. What stands out about the result is that this kind of spontaneous problem-solving is now demonstrated in an insect.”
Until now, scientists have largely believed that this kind of spontaneous problem-solving is only capable in large-brained vertebrates.
“What makes this behavior especially remarkable is that the bees had never been trained to roll the ball," says lead author Akshaye Bhambore from the University of Oulu. "This was a completely new challenge. Their behaviour appeared goal-directed, with successful individuals showing more directed movement patterns."
There are at least 265 species of bumblebee around the world, with almost all clustered in the Northern Hemisphere. Spending a lot of my childhood in New Zealand, I loved seeing these fuzzy balls hard at work on my grandmother's hydrangeas, but even they'd been introduced to the country in the 1800s.
In the fascinating experiments, the bees learned two separate pieces of information: that the blue artificial flower held a reward, and the ball that was also placed in the area was moveable but not a threat. Through previous tasks, the bees knew the flower contained the prize, but they'd never encountered the ball before.
“Another important aspect is that our bees were fully naïve,” Loukola says. “In many previous studies of insight-like problem-solving, the animals have had extensive experience with objects, test environments, or other problem-solving tasks. Here, the bees had never been trained to use the ball to reach the flower, and they had no previous experience with this kind of solution.
"We also designed the experiments to rule out simpler explanations such as accidental success, play behavior, trial-and-error learning, or direct visual guidance," the researcher adds.
In another test, scientists hid the flower from the bees to prevent them from relying on a sight trigger to find their reward target. The bee then had to push the ball through an opening before reaching the flower’s side. Even with this restriction, 16 out of 22 bees successfully rolled the ball through the opening and reached the flower.
In a final experiment, bees were shown a flower above one of two hidden compartments before the flowers were removed from the insects' view. The ball was placed in the middle, and whichever side the bee rolled it into ended the trial. If the bees were guessing, success should land around 50%.
Instead, 23 of 30 bees rolled the ball into the correct hidden compartment, and 16 of those successful bees did so directly without first trying the wrong side. You can see it in action in this video.
“By analyzing the bees’ behaviour across unusually stringent control experiments, we could show that they were not simply reacting to visual stimuli or moving the ball randomly,” says Bhambore.
“One moment the animal is exploring seemingly without direction, and the next it performs a highly efficient sequence of actions leading directly to the solution,” says co-author Ece Nur Akmeşe from the University of Helsinki. “Watching the bees solving the task was genuinely fascinating.”
While it's natural for us to anthropomorphize these kinds of discoveries, the scientists caution that the study doesn't prove that bees have minds like ours, but rather have more cognitive complexities than we often give insects credit for.
“We are not claiming that bees think like humans,” says Loukola, now a senior researcher at the University of Turku. “But our findings show that miniature brains can generate flexible solutions to novel problems in ways we are only beginning to understand.”
It's also worth appreciating the experimental design here – as insects are some of the most challenging species to work with in a laboratory. During my lab work, I realized quickly how difficult it is to observe insect behavior, let alone interpret it in a meaningful way.
“For over a century, spontaneous object-based problem-solving has mostly been studied in vertebrates,” says Loukola. “Our study suggests insects may belong in that conversation too.”
And while many studies, including this one from 2020, show that individual bees possess unique behaviors, we're still most likely to think of them and other colony species like ants as a collective with a "hive mind".
Studies like this are critical to better understanding the insect world, which makes up an estimated 90% of all species sharing Earth with us right now.
The research was published in the journal Science.
Source: University of Oulu
Fact-checked by Mike McRae
