Bees get a buzz from caffeine found naturally in flower nectar

March 7, 2013

You may need a cup of coffee to kick-start the day, but it seems honey bees also get their buzz from drinking flower nectar containing caffeine. Scientists from Arizona State University and the United Kingdom have discovered that caffeine improves a honey bee’s memory and may help plants recruit more bees to spread their pollen.

In an article published today in the journal Science, the researchers show that honey bees 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’s scent than those feeding on just sugar.  A honey bee feeds on the flower of a coffee plant. Download Full Image

Geraldine Wright, study leader and reader in Neuroethology at Newcastle University, explained that the effect of caffeine benefits both the honey bee and the plant. 

"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 Wright. “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.”

Julie Mustard, a co-author of the study and assistant research professor with ASU’s School of Life Sciences, in the College of Liberal Arts and Sciences, explains further.

“Flowers and nectar have evolved to attract pollinators to plants so that the bees will then carry the pollen to a flower on another plant of the same species,” said Mustard. “By including caffeine in their nectar, the plants are increasing the likelihood that the bees will keep returning to plants of the same species.”

In the study, researchers found that the nectar of Citrus and Coffea species often contained low doses of caffeine. They included ‘robusta’ coffee species used mainly to produce freeze-dried coffee and ‘arabica’ used for espresso and filter coffee. Grapefruit, lemons, pomelo and oranges were also sampled and all contained caffeine.

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 honey bees.

“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, professor at the Royal Botanic Gardens, Kew and the University of Greenwich's Natural Resources Institute. “However, it occurs at a dose that’s too low for the bees to taste but high enough to affect bee behavior.”

The effect of caffeine on the bees’ 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.

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

“Although human and honey bee brains obviously have lots of differences, when you look at the level of cells, proteins and genes, human and bee brains function very similarly,” Mustard said. “Thus, we can use the honey bee to investigate how caffeine affects our own brains and behaviors.”

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.

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

Sandra Leander

Manager, Media Relations and Marketing, School of Life Sciences


Study examines economic impact, community benefits of national monument

March 8, 2013

An ambitious study driven by Arizona State University is examining how national monuments and parks in the rocky mountain west can expand economic benefits and highlight and preserve the amenities that attract visitors and businesses to surrounding communities.

The 1,880,000-acre Grand Staircase-Escalante National Monument in southern Utah is the focus of the study led by Gyan Nyaupane, an associate professor and graduate program director with the School of Community Resources and Development in the College of Public Programs. Download Full Image

Through a $74,000 grant award from the U.S. Bureau of Land Management, the study aims to identify the relationships between community development, tourism and public lands using Appreciative Inquiry as a central driver of the research. Nyaupane, an international expert in the technique, describes Appreciative Inquiry as “a cooperative approach that focuses on identifying what is working well within a community or organization, understanding why it is working well and then building upon those strengths to encourage solutions and innovation.”

Ninety-six and 85.5 percent of the lands in Garfield and Kane counties, respectively, are public lands primarily managed by the three federal land management agencies: U.S. Forest Service; National Parks Service; and the Bureau of Land Management. Traditional commodity industries in the area, including agriculture, mining and timber, were becoming a smaller share of the overall economy in the region at the time of the designation.

“From the dozens of interviews we conducted in the 18 surrounding communities of the Grand Staircase-Escalante, we learned that the communities perceive tourism as a potential industry to support livelihoods in a declining rural economy,” Nyaupane said.

The preliminary findings are the result of a series of “mini-Appreciative Inquiry” sessions the ASU researchers have conducted over the last few months with local business owners and stakeholders from across the region.

“These AI sessions aim to evaluate the successes and strengths of the communities, which ultimately can lead to a new, tourism-related vision for the future,” Nyaupane said. “We hope that this project will encourage the exploration of some near-term and long-term actions to accomplish the vision and create a positive environment,” he said.

The team will lead an Appreciative Inquiry Summit on April 19 in Bryce Canyon City, Utah. Session findings will be summarized and provided to the communities involved.

“Millions of people visit national monuments, parks and recreation areas every year, creating opportunities to diversify the economy within surrounding communities in a number of ways,” said Kathleen Andereck, director of the School of Community Resources and Development. “Gyan Nyaupane’s research in the Grand Staircase-Escalante region is vital to helping raise public awareness regarding the important and beneficial role tourism can play in linking national parks and monuments to their surrounding communities and building better and more cooperative relationships among the communities and stakeholders.”

In addition to his research in southern Utah, Nyaupane’s recent study examining the economic impact of the Wings Over Wilcox Birding and Nature Festival (WOW) revealed that the annual event has infused nearly $2 million into the local economy during the last 20 years that the southern Arizona community has hosted the festival.

The 2011 “National Survey of Fishing, Hunting and Wildlife-Associated Recreation” indicates that $17.3 billion is spent annually on trip-related expenses to view wildlife nationwide. Bird-watching is estimated to generate 84 percent of all wildlife viewing.

The findings of the ASU study are helping to inform the efforts of festival organizers and Wilcox community leaders as they explore possible investments in birding and wildlife viewing enhancements that could help boost visitation to the area throughout the year.

Associate Director, Marketing & Communication, Educational Outreach & Student Services