Buff-tailed bumblebees have demonstrated an ability to recognize rhythmic patterns, surprising scientists who thought it required a large brain. Researchers trained the insects to distinguish sequences of flashing lights and vibrations, akin to Morse code. The findings suggest even small-brained animals can process abstract rhythms.
Andrew Barron at Macquarie University in Sydney, Australia, and his colleagues conducted experiments with buff-tailed bumblebees (Bombus terrestris). In initial tests, the bees learned to choose between artificial flowers: one with long flashes like dashes and another with short pulses like dots in Morse code. One offered sucrose as a reward, the other quinine as punishment. Even when both flowers contained only water, the bees selected the previously rewarding flash pattern with high accuracy, Barron reported. They also distinguished more complex patterns, such as dash-dash-dot-dot versus dot-dash-dot-dash. The team then introduced a maze where a vibrating floor at the junction signaled directions: one rhythm meant turn left for sugar, another turn right. Bees successfully followed these cues. Remarkably, when the vibrations were replaced with LED lights flashing the same patterns without further training, the population of bees transferred their learning, recognizing the rhythms regardless of whether presented as light or vibration, Barron said. This abstract rhythmic recognition was previously observed only in larger-brained animals like parrots, songbirds, and primates such as chimpanzees. Barron noted that understanding how bees achieve this with tiny brains could simplify designs for miniature drones and autonomous devices. 'An organism like a bee, with a bee-type brain, is able to abstract a rhythm is remarkable,' he said. The study appears in Science (DOI: 10.1126/science.adz2894).