A groundbreaking new study has demonstrated, for the first time, that an insect is capable of distinguishing between different lengths of visual signals.
In Morse code, brief flashes—or “dots”—represent the letter “E,” while longer flashes, or “dashes,” stand for “T.” Until now, recognizing the difference between such timing-based cues had been documented only in humans and a handful of other vertebrates, including macaques and pigeons.
Scientists at Queen Mary University of London created a customized maze to test whether bees could learn to associate flash duration with reward. Individual bees were trained to choose between two circles, each emitting either a long or short flash of light.
The short flash—the “dot”—signaled a sugar reward. The long flash—the “dash”—led instead to quinine, a bitter substance bees try to avoid. To eliminate the possibility that bees might use location to guide their decisions, researchers changed the positions of the “dot” and “dash” stimuli in every chamber of the maze.
Once the bees reliably headed toward the short-flash light that had been paired with sugar, the team removed all rewards and tested them again. This allowed them to confirm that the bees were responding to the duration of the flashes themselves—not the scent or appearance of the sugar.
“It was thrilling to see that bumblebees could actually learn to tell these different durations apart,” said PhD researcher Alex Davidson in a university release.
The bees’ choices in the reward-free tests remained consistent: most continued selecting the light with the previously correct duration, regardless of its position. These results, published in Biology Letters, provide clear evidence that bees can discriminate between long and short visual signals.
“Bees never encounter flashing lights in the wild, so their success on this task is extraordinary,” Davidson said. “Their ability to process how long a visual stimulus lasts may reflect a broader timing mechanism evolved for purposes like navigating through space or communication.”
He added that this capability might stem from a basic feature of neural systems—an intrinsic capacity of neurons to encode time duration.
Davidson and his supervisor, Dr. Elisabetta Versace, note that the neural circuitry behind time perception in insects remains poorly understood. Several hypotheses propose that animals may rely on one or multiple internal timing mechanisms.
Now that insects have been shown to discriminate between durations of flashing lights, researchers can use the tiny, sub–cubic-millimeter brains of bees to explore competing models of how animals perceive and process time.