Flowers’ caffeine aids bees’ memory

NEW YORK – Talk about a caffeine buzz: A new study says honeybees get a shot of caffeine from certain flowers, and it perks up their memory.

That spurs them to return to the same type of plant, boosting its prospects for pollination and the future of the plant species.

Maybe it shouldn’t be a surprise that one of the flowers is the coffee plant. Its nectar offers about as much caffeine concentration as a cup of instant coffee, according to researchers.

But some citrus plants serve caffeine too, albeit in lower concentrations. It’s found in the nectar of orange and grapefruit blossoms.

The caffeine helps a bee remember that the flower’s scent promises a tasty payoff, the researchers said. So the bee will seek out those flowers, transferring their pollen.

How could researchers tell the caffeine boosts a bee’s memory? In an experiment that used lab tools instead of flowers, they trained individual bees to expect a sugary drink when they smelled a certain floral scent. Some bees got nectarlike concentrations of caffeine in their drink; others didn’t.

Then after a day or more, they exposed the insects to the same scent and watched to see if they extended their feeding tubes in response, a sign they were ready to sip. After 24 hours, the bees that had gotten caffeine were three times as likely to remember as bees that hadn’t. After 72 hours, they were twice as likely.

Bees can’t taste caffeine at levels found in nectar, but the researchers found it affects certain brain cells involved in memory.

The work, by Geraldine Wright of Newcastle University in England and co-authors, was reported Thursday by the journal Science.