Hooked on caffeine? So are bees, and according to scientists at the University of Sussex, plants are using this little quirk to their advantage.
It’s well known that bees pollinate plants in return for nectar. But now researchers have found that, all else being equal, honeybees would rather have nectar that gives them a caffeine fix. Writing in Current Biology, the team suggests that some plants may be exploiting this preference to hijack bees’ attention - and pollination efforts – all for themselves.
Honeybees live in colonies and forage for nectar collectively. A bee that finds a nice, sugary source of nectar, flies back to its hive and performs something known scientifically as the ‘waggle dance’. The dance involves a lot of shimmying, buzzing and turning around, and functions to inform other bees about the best route back to the new nectar bar.
Usually, the gusto and frequency of these dances are related to the sugariness or quantity of the nectar being advertised. But here, the researchers observed more waggle dances for caffeinated sources of nectar than uncaffeinated ones, even when there wasn’t any difference in the quality of the nectar itself.
"The effect of caffeine is akin to drugging, where the honeybees are tricked into valuing the forage as a higher quality than it really is," explained co-author Roger Schürch of the University of Sussex and the University of Bern (if you want to know what bees wired on caffeine look like check out this video).
The researchers believe that plants lacing their nectar with caffeine are reaping rewards in the form of loyal patronage from the bees, and with it, increased pollination.
According to first author Margaret Couvillon, the next step could be to investigate whether plants also use other drugs to keep bees coming back for more. “It may be that chemistry is a popular way in which plants can get the upper hand on their pollinators,” she said.
In the meantime, better keep a lid on that cup of coffee.
by Catherine E. Offord