Passing on shared knowledge from one generation to the next is a hallmark of culture and allows animals to quickly adapt to a changing environment.
While commonly evident in species ranging from human infants to naked mole rats or infant songbirds, early social learning has now been documented in insects.
Publication in the journal Science, a University of California San Diego researcher and his colleagues uncovered evidence that social learning is fundamental to honeybees. Professor James Nieh of the School of Biological Sciences and his collaborators discovered that the “waggle dance”, which signals the location of critical resources to nestmates through an intricate series of movements, is enhanced by learning and can be culturally transmitted.
The study demonstrates the importance of early social cue learning in one of the most complex known examples of non-human spatial referential communication.
“We are beginning to understand that animals, like us, can pass on information important to their survival through communities and families. Our new research shows that we can now extend such social learning to include insects,” said Professor Nieh at the Department of Ecology, Behavior and Evolution.
A social insect with a highly organized social structure, honeybees help ensure the survival of their colonies by communicating the location of food sources to each other through a wagging dance in which bees circle around in figure-eight patterns while wagging their bodies beneath the central part of the dance.
The movements of the dance, performed at breakneck speed (each bee moves a body length in less than a second), translate visual information from the environment around the hive and the location of the sun into the distance, direction and even quality of the resource for nestmates.
Transmitting this information accurately is a remarkable feat because bees must move quickly across an often uneven hive surface.
Nieh and co-researchers Shihao Dong, Tao Lin and Ken Tan from the Chinese Academy of Sciences (CAS) set up experiments that tested the details involved in wagging dance communication. They created colonies to study the information transfer process between skilled forager bees and their younger, less experienced nestmates.
The experimenters created colonies where bees were never able to observe or follow wagging dancers until they first danced. These colonies consisted of young bees that were all the same age. Bees start dancing when they reach the right age and always follow experienced dancers before they try dancing for the first time. In these experimental colonies, therefore, bees were never able to learn from more experienced dancers.
“Bees without the opportunity to follow any dancers before they first danced produced significantly more disordered dances with greater swing angle divergence errors and miscoded distance,” the researchers noted in the paper.
In contrast, bees shadowing other dances in control colonies suffered no such problems. Like humans, for whom early exposure to language development is crucial, the bees acquired social cues that were encoded and stayed with them for life (about 38 days). Those who did not learn the correct waggle dance early on were able to improve by subsequently watching other dancers and by practicing, but they were never able to code distance correctly.
This distance encoding creates the different “dialects” of different honey bee species. In other words, the bees who could never observe other dancers in their critical early learning phase developed a new dialect that they retained for the rest of their lives.
“Researchers believe that bi-dialects are shaped by their local environments. If so, it makes sense for a colony to pass on a dialect that is well adapted to that environment,” Nieh said. The results therefore provided evidence that social learning shapes honey bee signaling, as it does early communication in many vertebrate species that also benefit from learning.
With their new findings, Nieh and his colleagues now want to understand the role of the environment in shaping secondary language. In the future, they would like to find out whether older, more experienced bees in the colony, who know the distribution of food sources in their environment, might be able to pass on an optimized dialect to the next generation.
They are also concerned that external threats may disrupt this early language learning. Several studies, including those by Nieh and his collaborators, showed the harm that commonly used pesticides can cause to bees.
“We know that bees are quite intelligent and have the capacity to do remarkable things,” Nieh said. “Several papers and studies have shown that pesticides can damage honey bee cognition and learning, and therefore pesticides can damage their ability to learn to communicate and potentially even reshape how that communication is passed on to the next generation of bees in a colony.”
About this social learning research news
Author: Mario Aguilera
Contact: Mario Aguilera – UCSD
Image: Photo credited to Heather Broccard Bell
Original Research: The results will appear from Science