Being able to learn complex skills from others is considered a special human talent. But now a study shows that even social insects are capable of highly developed forms of social learning: bumblebees can learn new behaviors from their own species that are too complex for them to develop on their own. Apparently they also have the fundamental ability on which our cumulative culture is based, say the researchers.
From hand axes to smartphones: over the course of our evolutionary history, humans have continually refined their techniques and problem-solving strategies until they sometimes reach an extreme level of complexity. These achievements are based on our ability to significantly expand individual intelligence: We can learn from our fellow human beings in a highly developed way. Social communication of very complex knowledge and complex behaviors is also possible. This ability forms the basis of the so-called cumulative culture on which our current technologies are based. But to what extent is complex social learning a unique feature of our species?
Social learning ability of bumblebees explored
At least the basic abilities are already attributed to our closest relatives in the animal kingdom. For example, techniques such as nut cracking in chimpanzees appear to be based on cultural transmission. But as the study results from the research team led by Alice Bridges from Queen Mary University of London now suggest, even some insects could have the basic cognitive requirements for cultural learning. Basically, studies in recent years have already shown that these creatures are by no means as simple as was long assumed. Bees in particular have shown cleverness: the social insects can not only solve tasks and remember successful strategies. It has already been documented that they can also copy certain behaviors from other animals. Bridges and her colleagues have now further explored the limits of this social learning ability of bumblebees.
First, the scientists taught some terrestrial bumblebees (Bombus terrestris) to operate a complex experimental system in order to obtain a sugar solution as a reward. The test animals first had to learn to move a blue-colored mobile element. This removed its blocking function. Only after this step were the bumblebees able to move a red-colored element, thereby gaining access to the sugar solution. “It was an extremely difficult task: the bumblebees had to learn two steps to get the reward, with the first behavior in the sequence going unrewarded,” says Bridges. Without help in the learning process, no bumblebee was able to discover the two-stage success strategy through trial and error. Only after an initial reward after the first step were the bumblebees finally able to learn that the sequence of actions leads to success. But once they had grasped the system, they then moved the two elements in the correct order, even without the first reward.
Video: If bumblebees have been trained or “trained” by a conspecific, they can solve this two-stage task. ©Alice Bridges
On the trail of insect culture?
Then the actual tests to examine social learning ability followed: The researchers placed a partner in the test facility with the trained bumblebees who had not previously gotten to know the system. These bumblebees were then able to observe how the experts successfully operated the two-stage mechanism. These witnesses were then confronted with the task alone. As the researchers report, five of the 15 experimental bumblebees actually turned out to be docile students: They also operated the mobile elements in the correct order without having to be rewarded after the first step. The scientists concluded that, through social learning, the insects had adopted a behavior that they would not have been able to develop on their own.
According to them, the study once again sheds light on what amazing achievements the small brains of insects are capable of. Specifically, the results challenge the traditional assumption that only more highly developed organisms are capable of complex forms of social learning. This even implies the exciting possibility that some form of cumulative culture could also exist in some insects. Senior author Lars Chittka from Queen Mary University of London concludes: “Think, for example, of the sophisticated nesting architecture of bees and wasps or the agricultural activities of ants that breed aphids and fungi. “It seems possible that some of the most fascinating abilities in social insects arose through imitation by clever innovators before eventually becoming part of the species-specific behavioral repertoire,” says the scientist.
Source: Queen Mary University of London, specialist article: Nature, doi: 10.1038/s41586-024-07126-4