Buff-tailed bumblebees use balls as ladders

In a study published June 4 in Science, researchers report that buff-tailed bumblebees can figure out on their own how to use a ball as a ladder to reach sugar from a fake flower. The bees solved the task without specific training for that exact trick, suggest

On the ceiling, a fake “flower” sat within reach of no bumblebee—at least, not without a new idea.

In research published in Science on June 4. buff-tailed bumblebees were tested in plexiglass arenas that were too small for them to fly. Their challenge was simple to describe and hard to execute: use a ball like a ladder to reach a blue ring printed on the ceiling. which represented a flower holding sugar.

The surprising part wasn’t that the insects could learn something from experience. It was that they appeared to solve the problem without being taught the specific solution.

“Spontaneous problem-solving is something that has never been shown in any invertebrate before,” says Olli Loukola, a behavioral ecologist at the University of Oulu in Finland.

Loukola also emphasizes why the result matters. “Our study is the first one where we can be 100 percent sure that these individuals don’t have any prior experience about any problem-solving tasks,” Loukola says.

Before releasing the bees into the arenas. the researchers taught two key associations: balls are moveable objects. and a blue ring—standing in for a flower—means food. After that instruction, the task depended on what the bees would do next. They were released into enclosures so constrained by size and barriers that there was “not much room for trial and error or playfulness. ” as behavioral ecologist Akshaye Bhambore. also of the University of Oulu. puts it.

More than 70 percent of the bumblebees figured out the solution.

The work didn’t rely on a straightforward line of sight either. The team added two rooms inside the enclosures—one that hid the “flower.” The addition was meant to nudge the setup toward goal-directed behavior rather than simple visual cue following. Even with that structure, the bees still reached the ceiling “flower” for a sugary treat.

Bhambore describes what the arenas demanded. “They had a goal in their mind, and they were able to understand the nature of the task,” Bhambore says. In practice, the bees had to find the flower plus remember where it was and retrieve the ball.

There was also a technical limitation shaping what the researchers could confirm. The arenas were too small for cameras to capture subtle behavioral cues that would reveal the moment humans might recognize as an “aha.”

The next step is to watch for those signals more closely. The team plans to use slow-motion cameras and video analysis to look for clues such as grooming when bumblebees have just figured out a puzzle.

The study lands in a broader field that has already been challenging old assumptions about insects. Bumblebees. the researchers note. are “brainy. ” with studies showing they may have emotions and can teach one another to score goals in a six-legged version of soccer. The new finding adds yet another skill to the group’s growing reputation—one that suggests. at least in this setup. problem-solving can emerge without a direct lesson for the trick itself.

For Loukola and colleagues, the bees’ success comes down to one essential detail: spontaneous problem-solving. The insects weren’t trained to use a ball as a ladder. They were trained only on what the components meant—and then, in the tight space of the experiment, they assembled the rest.

bumblebees buff-tailed bumblebees problem-solving spontaneous problem-solving invertebrates animal cognition behavioral ecology Science journal experimental arenas ball ladder pollinators