Despite being separated by hundreds of millions of years of evolution, humans and honeybees can show similar social behavior. New research has now found that antisocial bees may even share a similar genetic profile with people who have autism spectrum disorders, who themselves can struggle in social situations.
Within a hive, it is not unusual for some honeybees to be more active than others, as the insects take on differing roles. Guard bees, for example, react to intruders who threaten the hive, while nurse bees respond dotingly to the queen larvae. But researchers have found that there are individuals within these groups that are either hyper-responsive to both intruders and queen larvae, or seemingly indifferent.
After conducting experiments with 246 groups of bees from seven genetically distinct colonies, exposing them to both unfamiliar bees and queen larvae, they found that while most bees responded to at least one of the stimuli, around 14 percent of the insects were "unresponsive" to either. However, rather than simply suggest this antisocial bee behavior bears similarities to people with autism, they took a look at the genes that drive this behavior instead.
The team tested each bee in various social contexts and then analyzed which genes were being expressed in the brain. They found that more than 1,000 genes were regulated differently between social and nonsocial bees.
After comparing this gene expression to the ones known to be implicated in autism spectrum disorder, depression, and schizophrenia, they found that there was a significant overlap between the gene expression in the brains of unsocial bees and humans with autism.
"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," said Michael Saul, a postdoctoral researcher who helped lead the statistical analysis, in a statement.
“It's important to point out some caveats,” added Gene Robinson, co-author of the paper published in the Proceedings of the National Academy of Sciences. “Humans are not big bees and bees are not little humans. 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.”
Due to the vast amounts of evolutionary time separating both honeybees and humans, the results hint at a molecular underpinning of social behavior that may be shared across the animal kingdom and may offer clues about its evolution. While the sociality of both bees and humans almost certainly evolved independently, these results seem to show that both animals have utilized a similar underlying genetic toolkit to do so.
