STARBUCKS FOR BEES

To lure bees and other pollinators to their flowers, several plants offer even better bait than bright colors and attractive smells: caffeine. Researchers were surprised to discover the drug in the nectar of citrus plants, not just coffee plants. To figure out what it was doing there, they trained bees to associate certain smells with either sugar water or sugar water laced with a low dose of caffeine. They discovered that the bees that had sipped the caffeine remembered the related scents three times more often after 24 hours than bees that didn’t get a jolt, and twice as often after 72 hours—making it that much more likely they would return to those flowers. “Using a psychoactive drug” to influence a pollinator’s memory is “a new trick in the book for plants,” Lars Chittka, a bee researcher at Queen Mary, University of London, tells The New York Times. The bees’ reaction to the caffeine also explains why human beings guzzle so much coffee, tea, and caffeine-containing soda. “Caffeine absolutely influences our behavior,’’ says Abraham Palmer of the University of Chicago. “It changes mood and performance.’’