Bees get a buzz from caffeine You may need a cup of coffee to kick start the day but it seems honeybees also get their buzz from drinking flower nectar containing caffeine. Publishing in Science, researchers have shown that caffeine improves a honeybee鈥檚 memory and could help the plant recruit more bees to spread its pollen. In tests honeybees feeding on a sugar solution containing caffeine, which occurs naturally in the nectar of coffee and citrus flowers, were three times more likely to remember a flower鈥檚 scent than those feeding on just sugar. Study leader , Reader in Neuroethology at 缅北禁地, explained that the effect of caffeine benefits both the honeybee and the plant: 鈥淩emembering 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. 鈥淚n 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.鈥淪o, caffeine in nectar is likely to improve the bee鈥檚 foraging prowess while providing the plant with a more faithful pollinator.鈥�In the study, researchers found that the nectar of Citrus and Coffea species often contained low doses of caffeine. They included 鈥榬obusta鈥� coffee species mainly used to produce freeze-dried coffee and 鈥榓rabica鈥� used for espresso and filter coffee. Grapefruit, lemons, pomelo and oranges were also sampled and all contained caffeine.Co-author from the Royal Botanic Gardens, Kew and the University of Greenwich's Natural Resources Institute said: 鈥淐affeine is a defence chemical in plants and tastes bitter to many insects including bees so we were surprised to find it in the nectar. However, it occurs at a dose that鈥檚 too low for the bees to taste but high enough to affect bee behaviour.鈥�The effect of caffeine on the bees鈥� long-term memory was profound with three times as many bees remembering the floral scent 24 hours later and twice as many bees remembering the scent after three days.Typically, the nectar in the flower of a coffee plant contains almost as much caffeine as a cup of instant coffee. Just as black coffee has a strong bitter taste to us, high concentrations of caffeine are repellent to honeybees. Dr Wright added: 鈥淭his work helps us understand the basic mechanisms of how caffeine affects our brains. What we see in bees could explain why people prefer to drink coffee when studying.鈥�Dr Julie Mustard, a contributor to the study from Arizona State University, explains further: 鈥淎lthough 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. Thus, we can use the honeybee to investigate how caffeine affects our own brains and behaviours.鈥�This project was funded in part by the Insect Pollinators Initiative which supports projects aimed at researching the causes and consequences of threats to insect pollinators and to inform the development of appropriate mitigation strategies. Population declines among bees have serious consequences for natural ecosystems and agriculture since bees are essential pollinators for many crops and wild flowering species. If declines are allowed to continue there is a risk to our natural biodiversity and on some crop production. Professor Stevenson said: 鈥淯nderstanding how bees choose to forage and return to some flowers over others will help inform how landscapes could be better managed. Understanding a honeybee鈥檚 habits and preferences could help find ways to reinvigorate the species to protect our farming industry and countryside.鈥� You can read more about this team's work on pollinators in the press release Reference: Doi 10.1126. Science. published on: 7 March 2013
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