18 June 1999
Honeybees keep it in the family with chemicals
As families go, honeybees are pretty tight. You're quite unlikely, for example, to see a family of honeybees on the Jerry Springer show. But exactly how they can tell who is and who isn't family has been a mystery. They don't, after all, have a lot of visual cues - one bee looks pretty much like another, let's face it. However, research published in a recent edition of Nature identifies a chemical that increases a bee's ability to identify nestmates. It also makes the bees more aggressive to bees they aren't related to.
"This gives us the first glimpse of a neurochemical process in the brain that is involved in nestmate recognition," said Gene Robinson, a University of Illinois entomology professor and leader of the research team. "We know from studies of human stroke victims that there are specific regions of the brain involved in similar forms of recognition, but the role of brain chemistry in this context or in animals has remained obscure."
"Nestmate recognition is like a college rivalry," said Robert Hollingworth, a Michigan State University entomology professor and co-author of the Nature paper. "We recognize members of the rival school because of the colors they wear and once you see the difference it changes your behavior. So it is with the bees."
The brain chemical that underlies behavior is octopamine, a neurotransmitter that's similar to adrenaline in humans.
Bees injected with chemicals that acted like octopamine were friendlier to nestmates and significantly less enthusiastic towards strangers, Hollingworth said.
They joined researchers Laura Heuser from the University of Illinois, Urbana; and Yves LeConte and Fredric Lenquette in France to gain insight into the phenomenon of kin recognition.
It has been recognized that bees recognize family members by smell, but the chemistry behind that has been a mystery, Hollingworth said. Injecting the bees abdominally with compounds that mimic octopamine seemed to boost the bees' ability to process scent cues.
"Octopamine is the adrenaline of insects," Hollingworth said. "As adrenaline alerts us, we become more alert and receptive to sensory input. The nervous system goes into alert. Octopamine works that way in insects. They become more alert and more responsive to sensory clues."
The findings, Hollingworth said, open the door to greater questions of kin recognition - both in bees and other animals.