The Secret Minds of Bees
Life hasn’t been kind to honeybees lately. Nearly five years ago, beekeepers began to report that their charges were evacuating hives and dying en masse. (OnEarth first reported on this phenomenon in "The Vanishing" from our Summer 2006 issue.) Colony Collapse Disorder, the name scientists gave the mysterious phenomenon, claims about 30 percent of the insects per year in the United States alone and could be the result of any number of stressors, from pesticides to pathogens. Meanwhile, about one-third of the world’s crops require honeybee pollination to survive. The problem has scientists and farmers worried.
But how do the bees feel? In a new study, researchers at Newcastle University in the United Kingdom have taken the first step toward finding out. Honeybees, it seems, "are a lot more sophisticated than perhaps we thought," says co-author and ethologist Melissa Bateson. She and colleagues have shown that bees even appear to have emotions similar to ours.
Honeybees are pretty clever. They’re famous for communicating with their hive-mates by doing a "waggle dance" that tells them where to find pollen. And they can also be trained. So the Newcastle team strapped worker Carniolan honeybees (Apis mellifera carnica) into tiny harnesses and gave them two odors to smell. After one, they offered the bees a taste of sugar; after the other, bitter quinine. Pretty soon, the bees learned the difference between the two, sticking their tongues out for the smell they associated with sweets but not for the other.
Then, the researchers shook half the bees to simulate an invasion of the hive by a predator, such as a badger, and offered the bees the original two smells plus three new blends. The shaken bees still stuck their tongues out for the scent they associated with the sugar reward, but they were much less likely to do so for unfamiliar smells than the group that hadn’t been stressed. It seemed the unpleasant disruption had turned the shaken bees into pessimists. Even though there was an equal chance the strange smell would taste good, they more often believed it would taste bad.
That pessimistic behavior is a lot like what happens "when humans are anxious or depressed," Bateson explains. "For example, if I’m feeling down and a friend tells me that they don’t have time to go out with me, I interpret that as them saying they don’t like me rather than them just saying they don’t have time to spend with me." And like people with mood disorders, the agitated bees also had lower levels of the brain hormone serotonin.
Of course, even these intelligent insects will never be able to tell us what it’s like to be a bee. But scientists can observe their patterns of decision-making -- which are known as cognitive biases -- and compare them to those of humans who can report their moods. The similarities between pessimistic bee behavior and pessimistic human behavior could mean one of two things, Bateson says. "Either cognitive bias is a poor measure of self-emotions" in animals other than humans, or "bees have feelings" that may or may not be akin to ours.
Bateson says similar testing techniques could reveal other bee emotions, and that might at least give scientists a way of "asking" Apis mellifera -- as well as other species -- how they’re doing, on their own terms, before they reach a state of crisis. For now, they can only say for certain that "the stressed bee’s glass is half empty." With their population in serious decline, that could mean honeybees spend their busy lives expecting the worst.