Researchers at Queen Mary University of London have discovered that bumblebees can differentiate between short and long durations of light flashes, akin to recognizing Morse code signals. This ability, previously observed only in humans and select vertebrates, allows the insects to associate specific flash lengths with food rewards. The finding highlights unexpected timing capabilities in tiny insect brains.
In a pioneering study published in Biology Letters, scientists trained bumblebees (Bombus terrestris) to navigate a maze where two flashing circles emitted either short or long light pulses. One duration signaled a sugar reward, while the other indicated a bitter substance to avoid. To confirm the bees relied on timing rather than position, researchers swapped the locations of the flashing circles between maze sections.
Once trained, the bees consistently flew toward the light duration previously linked to sugar, even after rewards were removed and without relying on scents or other cues. This demonstrated their ability to learn and distinguish between the flashes, much like dots and dashes in Morse code, where short flashes represent 'E' and longer ones 'T'.
PhD student Alex Davidson, who led the experiments with supervisor Dr. Elisabetta Versace, expressed excitement about the results. 'We wanted to find out if bumblebees could learn the difference between these different durations, and it was so exciting to see them do it,' Davidson said. He noted the surprise given that bees do not naturally encounter flashing stimuli: 'The fact that they could track the duration of visual stimuli might suggest an extension of a time processing capacity that has evolved for different purposes, such as keeping track of movement in space or communication.'
The study raises questions about time perception in small brains. Circadian rhythms explain longer cycles but not the precise timing of flashes differing by fractions of a second. Dr. Versace emphasized broader implications: 'Many complex animal behaviors, such as navigation and communication, depend on time processing abilities. Processing durations in insects is evidence of a complex task solution using minimal neural substrate. This has implications for complex cognitive-like traits in artificial neural networks.'
Until now, such duration discrimination was known only in humans, pigeons, and macaques. This insect capability could inform evolutionary biology and efficient AI designs inspired by biological intelligence.