Does a version of autism affect honey bees similarly to the way it affects humans? In a close study of honey bees and their varying abilities to respond appropriately to social cues, researchers think that the human condition and the bee condition could be related, especially after finding similar genes in both species that affect behavior.
"Some honey bees are more active than others, and some appear indifferent to intruders that threaten the hive. This, in itself, is not unusual," explained study leader Gene Robinson from the University of Illinois at Urbana-Champaign. "Honey bees take on different roles at different stages of their lifecycle, and not every bee can - or should - function as a guard."
A little bit about “normal” honey bee behavior
Coming across occasionally indifferent honey bees was no surprise, but a bee behavior that turns heads would be bees who were also indifferent to the presence of queen larvae. According to bee experts, the normal response in this scenario is “diligent action,” not indifference. With this observation in mind, the “lack of social awareness” in the indifferent bees was compared to social behaviors observed in people with autism, which led to an analysis of the genetics behind the behavior. How are behavior and genetics related among species?
Robinson and his team conducted a study of 246 groups of bees from seven genetically distinct honey bee colonies and tested their social behavior in coordination with gene expression in the brain. They found that more than one thousand genes were regulated differently between different types of bees, including indifferent bees thought to be connected to human autism.
Next, they compared this library of genes to those genes known by scientists to be connected to human autism. Do several of the same genes also cause the indifferent, abnormal behavior observed in honey bees?
"We figured out a way to make an unbiased statistical test that will tell us whether a human gene list and a honey bee gene list overlap more or less than expected by chance," explained postdoctoral researcher Michael Saul, who headed up the statistical analysis portion of the study.
The statistical analysis revealed a significant overlap between indifferent honey bees’ gene expression and genes linked to human autism, but there was no significant overlap between indifferent honey bees and depression, schizophrenia, and other mental disorders. The connection seemed to be limited to autism.
"It's important to point out some caveats. Humans are not big bees and bees are not little humans,” Robinson clarified. “The social responsiveness depends on context, and is different in the two cases. Autism spectrum disorder is very complex, and unresponsiveness is not the only behavior associated with it."
With Robinson’s caution in mind, it's safe to say that it is likely that honey bees and humans independently evolved genes related to social behavior.
“There appears to be this kernel of similarity between us and honey bees, a common animal inheritance that potentially drives social behavior in similar ways," Saul explained. "We haven't proved this, but this work is telling us where to look for that in the future."
The present study is published in the journal Proceedings of the National Academy of Sciences.