A study shows that bumblebees can be trained to tell the difference between long and short light flashes.
Researchers at Queen Mary University of London have discovered, for the first time, that an insect can choose where to search for food by evaluating how long a light cue lasts. The study focused on the bumblebee Bombus terrestris, revealing that these insects can make foraging decisions based on the duration of a visual signal.
In Morse code, a brief flash or ‘dot’ represents the letter ‘E’, while a longer flash, or ‘dash’, represents the letter ‘T’. The ability to tell these two signals apart had previously been documented only in humans and a few vertebrate species, including macaques and pigeons.
Their findings were recently published in the journal Biology Letters.
PhD student Alex Davidson and his supervisor, Dr Elisabetta Versace, Senior Lecturer in Psychology at Queen Mary, directed the project exploring this capacity in bees. The team created a custom maze where each bee learned to locate a sugar reward at one of two circles that emitted either long or short flashes. In training sessions, a short flash or ‘dot’ signaled sugar, while the long flash or ‘dash’ indicated a bitter solution that bees naturally avoid.
Controlling for Position and Other Cues
In every section of the maze, the researchers shifted the locations of the ‘dot’ and ‘dash’ signals. This prevented the bees from using simple positioning to guide their decisions. Once the bees consistently headed toward the flashing circle linked to sugar, the team introduced a new test. The lights continued to flash, but no sugar was available. This allowed the researchers to determine whether the bees were choosing based on the light itself rather than any scent or visual trace left by the reward.
The results showed that the bees had indeed learned to identify the lights by how long they flashed. Most bees moved directly to the flashing duration that had previously indicated sugar, even when its position in the maze changed.
Alex Davidson said: “We wanted to find out if bumblebees could learn to the difference between these different durations, and it was so exciting to see them do it.”
“Since bees don’t encounter flashing stimuli in their natural environment, it’s remarkable that they could succeed at this task. 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.”
“Alternatively, this surprising ability to encode and process time duration might be a fundamental component of the nervous system that is intrinsic in the properties of neurons. Only further research will be able to address this issue.”
Understanding How Insects Track Time
The neural mechanisms involved in the ability to keep track of time for these durations remain mostly unknown, as the mechanisms discovered for entraining with the daylight cycle (circadian rhythms) and seasonal changes are too slow to explain the ability to differentiate between a ‘dash’ and a ‘dot’ with different durations.
Various theories have been put forward, suggesting the presence of a single or multiple internal clocks. Now that the ability to differentiate between durations of flashing lights has been discovered in insects, researchers will be able to test different models in these ‘miniature brains’ smaller than one cubic millimeter.
Elisabetta Versace continued: “Many complex animal behaviors, such as navigation and communication, depend on time processing abilities. It will be important to use a broad comparative approach across different species, including insects, to shed light on the evolution of those 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, which should seek to be as efficient as possible to be scalable, taking inspiration from biological intelligence.”
Reference: “Duration discrimination in the bumblebee Bombus terrestris” by Alexander Davidson, Ishani Nanda, Anita Ong, Lars Chittka and Elisabetta Versace, 31 October 2025, Biology Letters.
DOI: 10.1098/rsbl.2025.0440
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1 Comment
I think the researchers are overthinking things. I don’t think the bees have any sense of time. They just go from past experiences (in the study) of dealing with something that flashes a lot vs. something that flashes less. That’s even how I would think of it in that situation. I would think, wow, look how much that one is flashing and I got sugar from it before, let’s try it again. I get sugar. I see one that is not flashing as much and I get bitter stuff from it. Going to stay away from the lights that are not flashing very much. Time doesn’t enter into the thinking. I’ve simply learned to avoid the light that isn’t flashing a lot, and go to the one that is flashing a lot.