Humans aren’t the only ones who cannot function without their morning brew.
In a new study, researchers found that caffeinated bees are better equipped to find target crops — regardless of whether or not the crops contained caffeine.
In the study, published on Wednesday in Current Biology, researchers fed bees caffeinated food alongside a floral odor blend in their nest. They used robotic experimental flowers to “disentangle the effects of caffeine improving memory for learned food-associated cues versus caffeine as a reward.”
“Other studies have found that bees make more visits to caffeinated food sources, but it can be hard to work out whether that’s because the caffeine itself acts as a reward, or because it helps them remember that the particular characteristics of that location/flower indicate a good food source,” the study’s lead author Sarah Arnold, who is a senior lecturer of insect behavior and ecology at the University of Greenwich, told VICE.
According to the research, some bees were trained to associate a target odor resembling strawberry flowers with a sugary reward. One group of bees was given a caffeinated reward, while another group received a non-caffeinated version. A third group received the reward but did not learn to associate it with the strawberry.
Afterward, the bees entered a flight arena with floors covered with a green polypropylene sheet. The arena included both the strawberry-scented artificial flowers and flowers with a different “distractor odor.” Neither of the artificial flowers contained any caffeine. The electronic artificial flowers detected the bee visits and refilled automatically after 12 seconds.
Bees primed with caffeine made more initial visits to the robotic flowers emitting the target odor compared to the other bee groups. Seventy percent of the caffeinated bees went to the strawberry-scented flowers first, compared to 60% of the bees linking the strawberry scent to the non-caffeinated reward. Bees that did not learn the association visited the strawberry-scented flowers first at a 44.8% rate.
The caffeinated bees also had faster “floral handling” and flower-visiting speeds, revealing that food-locating behaviors in bumblebees can be enhanced by caffeine.
Surprisingly, the link between the strawberry odor and the sugar reward faded away as the study progressed. The caffeinated bees eventually stopped showing an affinity toward the strawberry scent, perhaps since they found out that both flowers yielded the same reward.
The study has wider implications for the impact of caffeine on overall crop pollination. If bees are caffeinated in their nests and taught to pollinate certain crops, they could boost farm production and reduce competition with wild bees.
“Providing caffeine and crop-specific odor to captive commercial bumblebees could prime inexperienced foraging bumblebees to visit a target crop preferentially to other flowers in the surroundings, reducing competition with wild bees and providing enhanced value for money from the colony,” the researchers concluded in the study.
