Bees Love Getting High on Caffeine

It’s fun for a few hours, but bad for the hive.

Heinz-Peter Bader / Reuters

Every so often, the pun gods smile down upon us mortals, and they deliver a set of circumstances so perfect, so tailor-made for cheesy wordplay, that to not take advantage would be like slapping the universe in the face. Like, for example, a study about caffeinated honeybees.

Thankfully, one such study was published today in the journal Current Biology. So here it is: Talk about your caffeine buzz, am I right?

Now that that’s out of the way, on to the science.

For the study, a team of biologists from the Univesity of Sussex set up two feeders containing a sugar solution, adding caffeine to one of the feeders in a concentration that would naturally occur in nectar. They then trained groups of honeybees from three different hives to collect the solution from one of the two feeders as they would nectar from a plant. Observing the bees over a three-hour period, the researchers found that they returned much more frequently to the solution with caffeine than the one without.

But the bees weren’t just caffeine fans; they were caffeine evangelists. During the same time period, the study authors monitored the bees’ “waggle dances,” the movements that bees use to direct one another to a food source, and also something that sounds like a fitting kind of dance for the overcaffeinated. Bees will modify their moves based on how much sugar a food source contains: The sweeter the nectar, the more frequently they’ll waggle.

But caffeine, as it turned out, overrode that connection: Although the two feeders contained identical amounts of sugar, the bees who had fed on the caffeinated solution were more likely to dance when they returned to the hive, and, once they got started, more likely to keep dancing repeatedly, like someone who’s just discovered something totally mind-blowing and won’t rest until his friends see it, too. Hey guys!, the caffeinated bee will tell the hive, wiggling furiously in a caffeinated haze. Guys. There’s a real cool thing happening nearby. You should check it out. Guys! Field trip!

“The effect of caffeine is akin to drugging, where the honey bees are tricked into valuing the forage as a higher quality than it really is,” Roger Schürch, a biologist at the University of Sussex and one of the study’s co-authors, said in a statement. “The duped pollinators forage and recruit accordingly.”

After every high, though, there’s the inevitable crash. The day after exposing their test bees to the two solutions, the authors let them loose to head back to the feeders, which this time were empty. Bees who had been exposed to caffeine returned to their feeder more frequently, and were less likely to investigate the other feeder on their foraging trips out of the hive.

The willingness to explore other options once a source has been exhausted, or what the researchers called “low site specificity,” is an adaptive behavior for bees: If one plant has yielded food, maybe its neighbors will, too. Loyalty to a single source is bad for the bees, good for the plant, as the study authors wrote: “Overall, caffeine causes bees to overestimate forage quality, tempting the colony into sub-optimal foraging strategies, which makes the relationship between pollinator and plant less mutualistic and more exploitative.”

That must … sting. (Sorry.)