Researchers find that bumblebees can learn a "non-natural" foraging task by observation, and spread it culturally within colonies.

Scientists worldwide are in search of key evolutionary ingredients for the cultural processes that define us as humans. As of now, two such components of culture-like phenomena that were thought of as exclusively human have been highlighted in other animals: spreading of new behavior via social learning, and the persistence of such behavior in groups over time.

New research suggests that in insect societies, seemingly complex social information acquisition processes – gradual consensus that occurs when honeybee swarms decide on new nesting locations – can sometimes be mediated by relatively simple learning mechanisms. This suggests that cultural processes may not necessarily require “sophisticated learning abilities.” Still, scientists have long studied and know that social bees have a variety of impressive cognitive skills. Examples of such feats include object categorization, spatial concepts, numerosity, and social learning skills that enable bees to acquire information about valuable food sources by observing other bees.

In this study, a group of researchers decided to test the spread of novel foraging techniques by performing “a transmission chain experiment,” where an experimentally induced innovation (string pulling for food) was “seeded” into a group of bees. This has never been explored in insects, providing a unique opportunity to determine what the basic cognitive requirements for “culture” might be.

The experiments showed that, on average, it took around 5 hours to successfully train an individual bumblebee to pull a string to get a food reward. Later, other bumblebees needed to be shown 5 instances of string pulling by an experienced demonstrator bee before being able to pull the string and subsequently demonstrate the technique themselves. It is worth mentioning that several bees solved the string-pulling task spontaneously, without any guidance, but it was a rare occurrence and might either reflect unusually explorative personalities of the individuals or simply luck in the process of random exploration.

The researchers provided some detail on the learning progress in bees, which is worth highlighting:

A bee lands beside another one who had already pulled a string for reward, gaining the reward without pulling herself/himself.

The observer learns to associate the other bee with reward and typically begins following her/him around, keeping in close contact as they walk.

The observing bee would be in direct contact with the string-pulling bee throughout the pull, usually not touching the string, although sometimes ineffectively manipulating the string herself/himself as well, and ultimately gaining reward through the other bee’s efforts.

The learners progressively change their foraging behaviors from observers to competent string pullers.

Overall, the results suggest colony and individual variation in social learning abilities of bumblebees. Furthermore, by combining different forms of learning, the bees used local as well as stimulus enhancement and trial-and-error approaches when learning string pulling by observation.

When assessing cultural diffusion, the researchers found that the new skill spread rapidly from a single knowledgeable individual to the majority of the colony’s foragers. There were actually several “generations” of learners – the longevity of the skill in the population could outlast the lives of informed foragers. All in all, the results indicate that bees may not differ from birds, dogs or apes in this respect. Just as in birds and mammals, an introduced novel behavior can spread via cultural transmission in social insect groups and, potentially, be retained over long periods.

This study complements recent work documenting social learning in fruit flies, as it suggests that insects possess the essential cognitive elements for cultural transmission and that they can, similarly to many other animals, gain critical information about their environment by observing others. Based on this, it’s important to realise that cultural transmission does not require the high cognitive sophistication specific to humans, nor is it a distinctive feature of ours.

The bees’ abilities to learn by observation, and spread and retain the knowledge of a novel foraging skill are undoubtedly impressive. The fact that social insects possess traits enabling “culture-like phenomena” highlights their cognitive complexity. Animal advocates can use the findings of this study when trying to bridge the gap between people and insects, showcasing their impressive societies, and human-like individual variability and learning mechanisms.