Caffeinated Bees Remember Their Nectar Sources
March 7, 2013

Bees Buzzed On Caffeine More Likely To Remember Nectar Sources

Brett Smith for - Your Universe Online

Most of us are more productive after the first fix of hot caffeine in the morning  — and according to a new study in the journal Science, so are honey bees.

In the study, a group of UK and US researchers found bees feeding on a sugar solution that contains caffeine are“¯three times more likely to recall a flower's scent than those given only sugar. The scientists said their findings not only reveal a novel interaction between plant and pollinators — they could also provide a clue about deep-seated brain chemistry that both bees and humans have in common.

"Remembering floral traits is difficult for bees to perform at a fast pace as they fly from flower to flower and we have found that caffeine helps the bee remember where the flowers are,” said lead author Geraldine Wright, from Newcastle University in the UK. "In turn, bees that have fed on caffeine-laced nectar are laden with coffee pollen and these bees search for other coffee plants to find more nectar, leading to better pollination.

"So, caffeine in nectar is likely to improve the bee's foraging prowess while providing the plant with a more faithful pollinator,” she added.

The researchers found nectar from coffee, grapefruit, lemon and orange plant all contained trace amounts of caffeine. The scientists said the presence of caffeine gives the plants an advantage over other competitors.

"Caffeine is a defense chemical in plants and tastes bitter to many insects including bees, so we were surprised to find it in the nectar,” said co-author Phil Stevenson from the Royal Botanic Gardens and University of Greenwich's Natural Resources Institute in the UK. “However, it occurs at a dose that's too low for the bees to taste but high enough to affect bee behavior."

The bees were three times more likely to remember the locations of their caffeinated nectar sources over a 24-hour period and twice as likely over a three day period compared to non-caffeinated plants.

"This work helps us understand the basic mechanisms of how caffeine affects our brains,” Wright said. “What we see in bees could explain why people prefer to drink coffee when studying."

"Although human and honeybee brains obviously have lots of differences, when you look at the level of cells, proteins and genes, human and bee brains function very similarly,” noted co-author Julie Mustard, of Arizona State University´s School of Life Sciences. “Thus, we can use the honeybee to investigate how caffeine affects our own brains and behaviors."

The study could have implications for beekeepers as well, which have seen their hives mysteriously decimated over the past decades.

"Understanding how bees choose to forage and return to some flowers over others will help inform how landscapes could be better managed,” Stevenson said. “Understanding a honeybee's habits and preferences could help find ways to reinvigorate the species to protect our farming industry and countryside."

Besides including various citrus flowers in their study, the team also used robusta coffee plants, which are typically used to produce freeze-dried coffee,  as well as arabica, which is used for most espresso and filter coffee.