Plants don’t make caffeine to help you get a morning buzz. In high concentrations, the chemical is a bitter deterrent against munching herbivores. But in smaller doses, according to a paper published today by Science, caffeine helps bees to remember a flower’s scent.
“Caffeine in nectar is likely to improve the bee’s foraging prowess while providing the plant with a more faithful pollinator,” the study’s lead author, Geraldine Wright of Newcastle University in the U.K., said in a statement.
It’s probably not a surprise to find caffeine in the nectar of species from the Coffea genus, but Citrus species also can produce caffeine, including in the nectar. In that sugary substance, the chemical is produced in a low enough dose that bees can’t taste it, but it does affect them, Wright’s group found. Using trained bees, the researchers showed that the insects were better able to learn a floral scent when it was laced with caffeine than when it only contained sucrose. And the bees remembered it for up to three days later.
This is a pretty good trick for a flower — drugging its client to return again and again, ensuring that the plant gets pollinated.
It’s not the first time that scientists have experimented with drugs on bees, though. A few years ago scientists in Australia gave cocaine to bees, but that time they had to paint the drug on the back of the insects.
Image Credit: Courtesy of Geraldine Wright and Science