The electrical fields that build up on honeybees as they fly, flutter their wings or rub body parts together appear to allow the insects to talk to each other, a new study suggests. Tests show that the electrical fields, which can be quite strong, deflect the bees’ antennae, which, in turn, provide signals to the brain through specialized organs at their bases.
Scientists have long known that flying insects gain an electrical charge when they buzz around. That charge, typically positive, accumulates as the wings zip through the air, much as electrical charge accumulates on a person shuffling across a carpet. And because an insect’s exoskeleton has a waxy surface that acts as an electrical insulator, that charge isn’t easily dissipated, even when the insect lands on objects, said Randolf Menzel, a neurobiologist at the Free University of Berlin in Germany.
Now, in a series of lab tests, Menzel and colleagues have studied how honeybees respond to electrical fields. In experiments carried out in small chambers with conductive walls that isolated the bees from external electrical fields, the researchers showed that a small, electrically charged wand moved close to a honeybee can cause its antennae to bend. Other tests, using antennae removed from honeybees, indicated that electrically induced deflections triggered reactions in a group of sensory cells, called the Johnston’s organ, located near the base of the antennae. In yet other experiments, honeybees learned that a sugary reward was available when they detected a particular pattern of electrical field.
Altogether, these tests suggest that the electrical fields that buildup on bees that results from their flight or movement are stimuli that could be used in social communication, the researchers reported online in the Proceedings of the Royal Society B.
The team’s findings “are very significant,” said Fred Dyer, a behavioral biologist at Michigan State University in East Lansing. “I hadn’t heard about the possibility that honeybees could use electrical fields.”
One of the honeybees’ most renowned forms of communication is the “waggle dance.” When the insects have located a dense patch of flowers or a source of water, they skitter across the honeycomb in their hive in a pattern related to the direction of and the distance to the site. Fellow worker bees then take that information and forage accordingly. The biggest mystery about the dance, Dyer said, is which senses the bees use to conduct their communication. “People have proposed a variety of methods: direct contact between bees, air currents from the buzzing of their wings, odors, even vibrations transmitted through the honeycomb itself,” he said.
But the team’s new findings introduce yet another mode of communication, Dyer said.
Front Section, Pages 13 on 09/29/2013