The study involved scientists from the University of Illinois, the U.S. Department of Agriculture, the Fyssen Foundation, the National Institutes of Health, the Illinois Sociogenomics Initiative, Purdue University, the University of Guelph and the National Program of Epidemiology in Mexico. It utilized microarray analysis to measure changes in gene expression in the brains of European honeybees and much more aggressive Africanized honeybees.
By comparing microarrays of bees in different environmental and social conditions, the researchers found changes occurring in the brain of a honeybee after it is exposed to alarm pheromones appear similar to the more gradual changes that occur over the bee's lifetime.
Even more striking, the scientists said, was the finding of a very similar pattern of brain gene expression in Africanized honeybees. They said in terms of brain gene expression, Africanized bees "look" as if they were just exposed to an alarm pheromone, even though they weren't.
"Some of the same genes associated with aggression that vary due to heredity also vary due to environment," said University of Illinois Professor Gene Robinson.
The findings, which might begin to explain how the evolutionary diversity of behavioral traits is achieved, appear in the Proceedings of the National Academy of Sciences.