Video: How bees sense a flower’s electric field

Bees don’t just recognize flowers by their color and scent; they can also pick up on their minute electric fields. Such fields—which form from the imbalance of charge between the ground and the atmosphere—are unique to each species, based on the plant’s distance from the ground and shape. Flowers use them as an additional way to advertise themselves to pollinators, but until now researchers had no idea how bees sensed these fields. In a new study, published online today in the Proceedings of the National Academy of Sciences, researchers used a laser vibrometer—a tiny machine that hits the bee hair with a laser—to measure how the hair on a bee’s body responds to a flower’s tiny electric field. As the hair moves because of the electric field, it changes the frequency of the laser light that hits it, allowing the vibrometer to keep track of the velocity of motion of the hair. When the bees buzzed within 10 centimeters of the flower, the electric field—like static electricity from a balloon—caused the bee’s hair to bend. This bending activates neurons at the base of bee hair sockets, which allows the insects to “sense” the field, the team found. Electric fields can only be sensed from a distance of 10 cm or so, so they’re not very useful for large animals like ourselves. But for small insects, this distance represents several body lengths, a relatively long distance. Because sensing such fields is useful to small animals, the team suspects this ability could be important to other insect species as well.