Bumblebees and humans share one key complex trait, new study suggests
“We are not 100% sure what exactly they use it for."
Bumblebees can recognize objects by piecing together information from multiple senses — an incredibly complex skill that scientists thought humans shared with only a handful of vertebrate animals.
In a new study, scientists show that bumblebees recognize objects by sight even if they have only ever touched the object before — and vice versa. The skill is the same one that allows you to find your shoes in a dark room without turning the light on, or your keys at the bottom of your bag without looking.
The results suggest bumblebees, like humans, can create elaborate mental images of their surroundings from sight or touch alone, and then store them for future reference. Making and remembering mental maps is an incredibly complex cognitive feat for such a tiny creature with less than a million neurons in its brain.
For years, scientists had thought this skill was the preserve of animals with far larger and more complicated brains. Humans can do it — and we have some 86 billion neurons in our brains. A few other vertebrate animals, including apes and dolphins, can also accomplish this feat, but again, all of these animals share a common trait — relatively big brains.
The discovery that bees can do it too also marks the first time an invertebrate has been shown to possess this complex trait.
“This contributes to our understanding of the inner world of an animal, to what's going on in its mind, so to speak,” Lars Chittka, professor at Queen Mary University of London and an author on the study, tells Inverse.
The study was published Thursday in the journal Science.
“We already knew that bees can recognize shapes. We already knew that they use both senses and that they can also use both at the same time,” Chittka says.
“The specific challenge here is that they can actually only use one sense at a time, but access the information acquired from the respective other sense.”
This also begs the question: How do bumblebees squeeze so much intelligence into these tiny, tiny brains?
Inside the bee brain
To make their discovery, the researchers trained bees to recognize a cube and a sphere, one of which contained sugar water, while the other did not. Some bees trained in the dark, meaning they could not see the objects, while other bees trained in the light, but the objects were behind plexiglass, meaning they could not touch the objects.
When the conditions were switched, the bees that had only ever known what the reward object felt like were able to use sight to spot it correctly from afar without being able to touch it. The same was true for the bees that only knew what the reward looked like.
The mushroom body is part of the insect brain that receives sensory information, and bumblebees have very large mushroom bodies.
Whether the bees were solving this task by storing a picture of the entire shape — seeing the cube or sphere in their head — or whether they were recollecting a memory of more discreet object features — knowing the object has a general roundness or an edginess — is unclear, but the findings suggest we have underestimated bees' powerful memories.
“We are not 100 percent sure what exactly they use [the skill] for,” Gerhard von der Emde, professor at the University of Bonn, tells Inverse. But the fact that bees can rely on multiple senses to thrive points to their evolutionary success.
“To have several senses is always better than to just have one sense," von der Emde says. He was not involved in this study.
Bees searching for their reward shape in the dark.
Scientists should try to conduct more behavioral experiments to validate the findings and help parse out exactly what the bees are capable of, von der Emde says.
"What can they do and what can they not do?” are the key questions to answer now, he says.
“Maybe we probably have to go into the brain and record from certain nerve cells to find out all the information is processed.”
Do bees have consciousness?
The results suggest that completely different kinds of brains to those of humans can give rise to intelligence in different ways. They also jibe with the idea that certain animals develop the same cognitive skills but different brain features in order to adapt, survive, and thrive in their habitats.
“That is really remarkable. The problem is solved in a different way, but coming to the same result,” von der Emde tells Inverse.
Bees are already appreciated for their other complex behaviors, like building and organizing colonies, and using dance as a form of communication, Chittka says. But the new findings add an extra layer of nuance.
“[Bumblebees] were still regarded as sort of cleverly designed robots without very much going on inside their minds,” Chittka says.
“There was not necessarily an appreciation that they had a kind of virtual image of these flowers floating around in their heads. But what this new work, I think shows is that there is a kind of awareness of objects in the world around the animal.”
“I think we need to respect them for other reasons than that they're useful for pollinating our crops.”
Chittka and his colleagues ultimately want to answer a bigger question: Do bees have a form of consciousness?
One of the next things they hope to test is the extent to which bees make plans for the immediate future.
Video of test in light, but barred from touching objects. Bee spends more time exploring cubes, the shape they previously learned in the dark was rewarding.
The results also hold ethical implications for bee conservation, Chittka says. Other endangered animals like Arctic seals and Siberian tigers can seem aware of their changing environment and threats, which tends to inspire more empathy in us humans, he says.
We do not extend the same sort of sympathy to insects, however. That's because they are generally still thought of as unintelligent, or robotic.
“I think our increasing understanding of the richness of the inner world of insects lens also feeds into these conservation campaigns," Chittka says.
“I think we need to respect them for other reasons than that they are useful for pollinating our crops.”
