A new study finds that bumblebees can process the duration of flashes of light and use the information to decide where to find food.
According to doctoral student Alex Davidson, senior lecturer in psychology at Queen Mary University of London, and his supervisor Elisabetta Versace, this is the first evidence of such an ability in insects. Versace told CNN that the discovery could help resolve a long-standing debate among scientists about whether insects are capable of processing complex patterns.
“In the past, it was thought that they were just very basic reflex machines with no flexibility,” she said.
To reach their discovery, the team set up a maze through which individual bees traveled when they left their nest in search of food.
The researchers presented the insects with two visual cues: a circle that would flash with short flashes and the other with a longer flash of light.
Approaching these respective enclosures, the bees will find sweet food in one, which they like, and bitter food, which they do not like, in the other.
The circles were in different positions in each room of the maze, but the bees learned to fly toward the short flashes of light associated with the sweet food at different times.
Davidson and Versace then tested the bees’ behavior when there was no food present, to rule out the possibility that the bees could see or smell the sweet food.
They found that the bees were able to tell the circles apart based on the duration of the light flashes rather than other cues.
“And in this way, we show that the bee is actually processing the time difference between them to guide its forage choice,” Davidson said.
“We were pleased to see that, in fact, bees can process stimuli they have never seen before during evolution,” Versace said, referring to flashes of light.
“They are able to use innovative stimuli to solve tasks in flexible ways that they have never seen before,” Versace said. “I think it’s really remarkable.”
Researchers say bumblebees are one of only a few animals, including humans and other vertebrates like macaques and pigeons, that have been found to be able to distinguish between short and long flashes, in this case between 0.5 and five seconds.
For example, this ability helps humans understand Morse code, in which a short flash is used to transmit the letter “e” and a longer flash is used to transmit the letter “t”.
It’s not clear how bees are able to estimate time periods, but the team plans to investigate the neural mechanisms that allow the insects to do so.
The scientists plan to conduct similar research with bees that are able to move around freely in colonies, not individually, and investigate the cognitive differences that allow some bees to learn to assess time periods faster than others.
Davidson hopes the results will help people understand that bees and other insects are not simple “machines that operate essentially by instinct,” but rather “complex animals with internal lives that have unique experiences.”
“In fact, they have complex cognition, learning and memory, and flexibility in behavior,” he said.
This could help people understand bees as unhelpful pollinators, Versace said.
“They’re not just machines for our purposes,” he said.
According to Davidson, these findings also raise important ideas about our own understanding of time.
“It’s a fundamental part of our lives and the lives of all animals,” he said, “but we still don’t really understand what time is and how we deal with it in our brains.”
“I think this study is really interesting because it shows it’s not just a human question,” Davidson said.
The researchers reported their findings on Wednesday in the journal Biology Letters.
According to Cynthia Akemi Oei, a postdoctoral research fellow at the Center for Biodiversity and Environment Research at University College London, the study shows that “bees have a sophisticated sense of time.” Oei was not involved in the new research.
“This finding makes perfect sense, because bees must carefully manage their time to maximize rewards and minimize the costs of returning to the nest,” he said.
“Such studies not only help understand insect cognition, but also shed light on shared and unique features of their neuronal functions, providing valuable insights into the field.”
Julian Trosienko, a visual ecologist at the University of Exeter in England who was not involved in the study, told CNN that the results suggest that bees “may be using learning that can measure the length of time.”
The method shows that bees can learn using information from outside their normal ecological context, “which I find fascinating because it shows how this type of general learning can be achieved with systems many orders of magnitude smaller than the birds and rodents on which previous work has focused,” he said.
“So a big brain is not always necessary to show really impressive cognitive ability.”
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