Bees, even of the same species, vary widely in their propensity to attack people. Entomologists seeking to understand why some bees are peaceful and others hostile have found the genetics of the hive matters much more than those of the individual bee.
The question as to whether genetics or environment is the prime determinant of behavior is one of the great debates of our time. Unsurprisingly, the situation is far more multifaceted than that simple description suggests. The latest layer of complexity to be revealed is the way community genetics influence individuals.
Honey has so many fans bees evolved stings against those who would steal their gold. Some attack anyone who looks like a possible danger, but since stinging equals death, others restrict their battles to more unambiguous threats.
Interbreeding between East African lowland and European subspecies of honeybees produced a new strain of so-called “Africanized honeybees” that elicited so much fear they inspired several horror movies. Despite their fierce reputation, some Africanized honey bees, particularly in Puerto Rico, are considered “gentle”. Professor Matthew Hudson of the University of Illinois at Urbana-Champaign is investigating what causes this variation. “We wanted to know which parts of the genome are responsible for gentle behavior versus aggressive behavior,” Hudson said in a statement.
Hudson had people strike the tops of nine hives with a block and collect 177 bees that either attacked decoys or continued foraging for genetic analysis. At first, Hudson thought he had struck out. He and colleagues couldn’t find anything in the genomes of soldier bees, or foragers for that matter, that reliably predicted whether they would respond aggressively or peacefully to light disturbance.
However, in Proceedings of the National Academy of Sciences Hudson and co-authors report something much more interesting. A comparison of the average genome across the hive was predictive. “Mostly these bees’ genomes look like Africanized bees,” Hudson said. “But there was one chunk that looked very European. And the frequency of that European chunk in the hive seems to dictate how gentle that hive is going to be to a large extent.”
In other words, even if a bee’s personal genetics suggest it is prone to aggression, if most of its hive-mates have peaceable DNA, there is little to fear from it attacking, at least without good cause.
“We’ve always thought that the most significant aspects of an organism’s behavior are driven, at least in part, by its own genetic endowment and not the genomics of its society,” Hudson said.
“Our findings also add to the long-running “nature vs. nurture” debate, as the “nurture” (colony environment) of the bees appears to be the strongest factor in determining aggression,” the paper notes. “[But] nurture in turn was determined by “nature” in this case, as previously described in the indirect genetic effects literature.”
Hundreds of millions of years of evolution separate humans from bees, so any extrapolations require extreme care. Nevertheless, the findings certainly call for a more sophisticated approach than simply assuming an individual’s genes determine their response to attack. Nor do they stand alone. A genetic predisposition to addictive behavior among someone's peers is a risk factor for smoking, even without those genetics in the individual.
Aside from any implications for other animals, the research could be useful for apiarists. Africanized bees are hardier and more resistant to disease than their European cousins. Were it not for their aggression, beekeepers in warmer regions would prefer them, so there is plenty of interest in learning whether we can get the honey without the attitude.