Many humans love to start their day with a hot cup of coffee, and new research suggests honeybees feel the same way.
A team of researchers observed honeybees generally choose caffeinated nectar over non-caffeinated nectar, the University of Essex reported. The findings also suggest that the plants are using the addictive caffeine to trick bees into visiting them repeatedly, increasing pollination.
"These new findings are a reminder that, while mutually dependent, the interests of plants and pollinators don't always align," said study leader Margaret Couvillon, of the University's Laboratory of Apiculture and Social Insects. "Some plants, through the action of a secondary compound like caffeine that is present in nectar, may be tricking the honey bee by securing loyal and faithful foraging and recruitment [behaviors], perhaps without providing the best quality forage."
Past studies have found bees are better at learning and have improved memories when they are under the influence of caffeine, suggesting a role for the reward pathway in bees' brains.
"I could not help but wonder how caffeine would affect the natural behaviours as seen in the field," Couvillon said.
To make their findings, the researchers observed bees' response to a sucrose solution with or without a dose of caffeine similar to what occurs naturally in some plants. They determined the caffeine caused the bees to exhibit more foraging behaviors. The bees directed their peers to the caffeinated samples through what is referred to as a "waggle dance" four times more frequently than non-caffeinated samples. The bees were more likely to return to caffeinated sites, and less likely to search for other resources. The researchers noted this could be problematic if the caffeinated nectar were to run dry.
The findings were published in a recent edition of the journal Current Biology.