Latest News

March 25, 2019

Honey Integrity Task Force Forms to Ensure

Highest Quality Across All Honey Products

Industry group is working on multiple fronts to protect honey purity


PHOENIX, Ariz. (March 12, 2019) – Representatives from the entire U.S. honey industry have formed a working group and pledged to cooperate on a range of strategies designed to ensure the purity of honey in the United States.  The Honey Integrity Task Force is leading a comprehensive effort to reduce instances of economically motivated adulteration of honey reaching U.S. consumers, and to ensure that honey has the proper country of origin label.  The industry watchdog group includes beekeepers, importers, packers, producers and marketing cooperative members along with an organization that specializes in honey supply chain management.


Honey is one of nature’s original products, and it is made by bees with no additives or preservatives of any kind.  It is one of many food products that can be vulnerable to what is known as economically motivated adulteration, a term used when unscrupulous players within the honey supply chain use cheaper ingredients to lower their production costs and then sell the product as pure honey. 


The Honey Integrity Task Force is now embarking on a number of initiatives designed to strengthen checkpoints in the honey production and supply chain so that consumers can have even greater confidence in the purity of honey products they are purchasing. 


Expert opinion on adulteration prevention

In 2018, the Task Force commissioned a study on honey adulteration from UCLA professor Dr. Michael Roberts, a food fraud expert.  Dr. Roberts made a series of recommendations to the group on additional steps the industry could take to police itself and minimize the chances that a product labeled as honey will be adulterated with sugar or syrup.  Some of the initiatives being pursued now by the Task Force were the result of the recommendations in the Dr. Roberts report. 


Food Chemicals Codex Honey testing standard

A Honey Expert Panel has been formed to support the Food Chemicals Codex (FCC) including members of the Task Force. The goal of the panel is to develop an international identity standard for honey, with an emphasis on the need for purity and country-of-origin testing, to be included in the FCC.  The FCC is published by U.S. Pharmacopeia (USP), a nonprofit organization whose mission is to improve global health through public standards and related programs.


Random Testing of Retail Honey on Shelves

The Task Force has committed to conducting independent tests of honey products sold in U.S. grocery stores.  The group will work with independent labs to test for adulteration and plans to make the results of the tests public.


Submitted comments to United States Department of Agriculture (USDA)

Working together as an industry voice, the Task Force submitted comments to the USDA for honey’s Commercial Item Description (CID), which is a product description that concisely describes the most important characteristics of a commercial product.  Having a Honey CID will help enforce the highest quality standards.  


Met with Customs and Border Protection (CBP)

The Task Force met with CBP as well as Homeland Security Investigations (HSI) to identify areas where collaboration could be most valuable, such as collecting global samples for their database and refining the definition of honey. 


“It is encouraging to see the entire honey industry working together on the issues that affect us all.  Consumers in the U.S. deserve to know that the honey they purchase is pure, and that they can trust the labeling on their favorite honey products.  We are committed to the purity and integrity of our industry’s products, and we will do everything in our power to insure the integrity of our supply chain” said Christi Heintz, Director of the Honey Integrity Task Force. 





Honey Integrity Task Force Finds No Adulteration in US Retail Test

Work being done by the industry to ensure honey’s purity will continue



PHOENIX, Ariz. (March 19, 2019) – An independent test of top selling honey products sold in U.S. grocery stores found zero instances of adulteration.  In all, the 30 top selling products were tested, all of which represented the top items in the honey category as determined by Nielsen’s recent 2018 honey category research.  These brands account for approximately 40 percent of the honey sold in the U.S. retail market.  The study was commissioned by the Honey Integrity Task Force, an organization made up of representatives from the entire honey industry including importers, packers, producers, marketing cooperative members and an organization that specializes in honey supply chain management.


An independent third party company, RQA Inc., was hired to conduct the study.  They pulled two sets of each of the 30 samples from retail shelves across the country.  The honey sample brand names were masked, and the samples were sent to two independent German laboratories that specialize in honey testing, QSI and Intertek.


Each lab conducted two adulteration tests, the AOAC-approved 998.12, 13C-Isotope Mass Spectrometry and 13C-IRMS (EA IRMS)/ +LC-IRMS method for C4/C3 adulteration.  Both tests are well recognized methods designed to determine if any sugar was added to the honey.


Of the 28 products that were labeled at retail locations as pure honey, the tests from both labs confirmed the samples were not adulterated.  Two of the 30 products were actually labeled as honey blends, not pure honey. Both labs correctly identified them as “adulterated.”  One was an imitation honey made with maltitol syrup and the other was a combination product with both corn syrup and honey.


“Consumers have every right to expect they’re getting pure honey when they purchase something labeled as such,” said Christi Heintz, Director for the Honey Integrity Task Force.  “While the results of this study are very encouraging, we certainly aren’t declaring victory.  We view it as validation that our efforts are working, and we hope it gives consumers more confidence in a system that’s been created to protect them.  However, our work is never complete and we will continue to work hard and find newer and better ways to ensure the purity of our products.”


The Honey Integrity Task Force plans to conduct more independent testing of honey products in 2019.


Honey is one of nature’s original products, and it is made by bees with no additives or preservatives of any kind.  It is one of many food products that can be vulnerable to what is known as economically motivated adulteration, a term used when unscrupulous players within the honey supply chain use cheaper ingredients to lower their production costs and then sell the product as pure honey.  The honey industry has put safeguards in place over the years to minimize the chances that a product labeled as honey will be adulterated with sugar or syrup.




For Media Inquiries and Press Information:

Kylie Banks:, (310) 754-4126

Honey Bee Health Coalition members release corn, canola guides for bee protection

National Corn Growers Association, U.S. Canola Association partner with Coalition to develop best practices growers can use to reduce risk to honey bees, other pollinators


Two Honey Bee Health Coalition member organizations — the National Corn Growers Association and the U.S. Canola Association — recently unveiled best management practices for growers to help protect bees in and around corn and canola fields

At roughly 80 million acres, field corn covers more land than any other crop in the country, and in the Midwest Corn Belt it often makes up 40 percent of the landscape or more. The corn best management practices (BMPs), facilitated by the Coalition, identify potential impacts of agricultural practices on bees at each stage of production and recommend ways to mitigate those impacts, such as specific strategies for reducing dust and drift while planting pesticide-treated seed.

“While corn does not rely on honey bees for pollination, bees depend on neighboring plants for forage," said Nathan Fields, National Corn Growers Association vice president of market development. "As good stewards of the land, corn growers can follow these BMPs to help protect honey bee health, ensuring productive agricultural systems for all.”

Canola is another important crop for pollinator protection because canola flowers are very attractive to bees. And for growers, the stewardship recommendations in the Coalition-facilitated canola BMPs are even more of a win-win.

“Canola is an excellent source of nutrition for bees, which are essential for hybrid canola production,” said Rob Rynning, U.S. Canola Association president. “These beneficial pollinators also increase seed germination and encourage higher canola yields with better ripening."

Corn growers who rotate with soybeans could also see added benefits from their pollinator stewardship because bees can increase soybean yields by up to 18 percent, according to a 2005 study

Both the corn and canola guides feature season-long BMPs for growers and beekeepers and a summary of key practices. These include:


  • communicating about hive locations, crop management practices, and any related concerns and coordinating with beekeepers

  • checking extension recommendations, considering multiple strategies for pest control, and verifying in-field needs before applying pesticides

  • planting and preserving flowering plants in non-crop areas


“Many growers don't realize that how they spray, and what time of day especially, can hurt bees," said Chris Hiatt, vice president of the American Honey Producers Association and a member of the Coalition's Steering Committee. "These BMPs will promote better communication between beekeepers and growers, reduce pesticide exposure, and improve bee health in the spring and summer, a crucial time for beekeepers recovering from significant winter colony losses."

Each set of best practices, available online for free download, was developed by an expert team of agronomists, entomologists, beekeepers, and extension and regulatory agents and reviewed by growers, crop consultants, agribusiness representatives, retail suppliers, conservation NGOs, and other stakeholders.

Both crop associations announced the new BMPs at the 2019 Commodity Classic tradeshow in Orlando, Florida, on Friday, March 1. This made corn and canola the latest crops to develop BMPs for pollinator protection with the help of the Coalition. The United Soybean Board released its soybean BMPs in 2018, and the Coalition is now pursuing opportunities with other crop and landscape associations.

About the Honey Bee Health Coalition


The Honey Bee Health Coalition brings together beekeepers, growers, researchers, government agencies, agribusinesses, conservation groups, manufacturers, brands and other key partners to improve the health of honey bees and other pollinators. Its mission is to collaboratively implement solutions that help achieve a healthy population of honey bees while also supporting populations of native and managed pollinators in the context of productive agricultural systems and thriving ecosystems. The Coalition focuses on accelerating the collective impact of efforts in four key areas: forage and nutrition; hive management; crop pest management; and communications, outreach and education. 


The Honey Bee Health Coalition is a project of the Keystone Policy Center, a nationally recognized nonprofit that brings together diverse stakeholders to find collaborative, actionable solutions to public policy challenges.

Monsanto Beats Farmers in Suit Over Pesticide-Resistant Seeds

‘Indirect purchasers’ can’t bring antitrust claims

Licensing agreement not a direct purchase

By Mike Leonard | March 14, 2019 10:24AM ET

Monsanto Co. has fended off an antitrust class action by farmers who say they are forced to buy its herbicide-resistant seeds because the company’s herbicides “drift” from one crop to another.

The farmer plaintiffs bought their seeds from downstream retailers, not from Monsanto itself, so they failed to overcome the bar on Sherman Act claims by “indirect purchasers,” Judge Stephen N. Limbaugh Jr. of the U.S. District Court for the Eastern District of Missouri ruled March 13.

“Courts have uniformly declined to recognize exceptions to the direct purchaser rule where the plaintiff did not actually transact its purchase with the alleged monopolistic supplier,” Limbaugh wrote.

He dismissed without prejudice the suit’s monopolization claims under Section 2 of the Sherman Act, part of a consolidated multidistrict litigation against the chemicals giant.

The plaintiffs argued that Monsanto’s “XtendiMax” brand of dicamba-based herbicides—which the company advertises as less prone to drift—had forced them to “defensively purchase” XtendiMax-resistant seeds. The need to buy those “Xtend” seeds defensively artificially boosted demand for them, giving Monsanto the chance to reap monopolistic profits, the suit claimed.

The judge rejected the plaintiffs’ argument that even though they didn’t buy their seeds from Monsanto, the mandatory licensing agreement they signed had made them direct purchasers of the “trait”—XtendiMax resistance—that the seeds incorporated.

A similar claim failed in a 2006 lawsuit involving Microsoft software, Limbaugh noted. In that case, consumers who signed a licensing agreement with Microsoft after buying its products from third-party retailers still counted as indirect purchasers, he said.

The judge also said the argument for an “agency exception” to the indirect purchaser rule, covering situations in which a retailer sold products on behalf of an upstream manufacturer, was “a stretch.”

The plaintiffs are represented by Gray & Ritter. Bryan Cave LLP represents Monsanto.

The case is In re Dicamba Herbicide Litig., E.D. Mo., No. 18-md-2820, 3/13/19.

To contact the reporter on this story: Mike Leonard in Washington at

A hive of activity: Using honeybees to measure urban pollution

Bees are startlingly intelligent creatures who form an essential part of the planet’s ecosystem, and now a new study shows they could help us understand urban pollution as well. A team from the Pacific Centre for Isotopic and Geochemical Research (PCIGR) at the University of British Columbia has found an innovative way to measure the level of source of pollution in urban environments: by analyzing honey.

The team analyzed honey collected from urban hives in Vancouver and found the tiny amounts of lead isotopes in the honey were distinctive and could be used as a “fingerprint” to identify where the lead originated from. This meant the team could track the relationship between the location of a hive and sources of pollution such as traffic or industrial activity very closely.

“The instruments at PCIGR are very sensitive and measure these elements in parts per billion, or the equivalent of one drop of water in an Olympic-sized swimming pool,” Dominique Weis, the paper’s senior author and director of PCIGR, explained in a statement.

“The good news is that the chemical composition of honey in Vancouver reflects its environment and is extremely clean,” Kate E. Smith, lead author of the study and Ph.D. candidate at PCIGR, said. “We also found that the

concentration of elements increased the closer you got to downtown Vancouver, and by fingerprinting the lead we can tell it largely comes from manmade sources.”

The team also compared the fingerprints of the honey from Vancouver to other locations in the British Columbia area. They saw that the lead in urban locations was not from a local source of naturally occurring lead, suggesting it originated elsewhere. “We found [honeys from downtown Vancouver] had fingerprints similar to aerosols, ores, and coals from large Asian cities,” said Weis. “Given that more than 70 per cent of cargo ships entering the Port of Vancouver originate from Asian ports, it’s possible they are one source contributing to elevated lead levels in downtown Vancouver.”

The scientists gathered data in partnership with Hives for Humanity, a non-profit which promotes urban beekeeping, and they see potential for citizen scientists in other locations to collect honey samples too. Next they want to investigate how honey sampling can complement other environmental monitoring techniques like air and soil monitoring.

The study is published in the journal Nature Sustainability.

CRISPR gene-editing used to understand links between diet and genetics to make a future honey bee queen

How a queen bee achieves her regal status that elevates her from her sterile worker sisters has been a long-standing question for scientists studying honey bees.

To get at the heart of the question, scientists have now used for the first time the gene-editing tool CRISPR/Cas9 to selectively shut off a gene for necessary for general female development.

By doing so, they have shown that a dramatic difference in gonad size between honey bee queens and their female workers in response to their distinct diets requires the switching on of a specific genetic program, according to a new study published in the open-access journal PLOS Biology by Arizona State University honey bee expert and School of Life Sciences Regents' Professor Robert Page, and colleagues Annika Roth and Martin Beye of Heinrich-Heine University in Dusseldorf, Germany.

"This study focused on a critically important and missing connection between nutrition and the developmental processes that make a queen,” said Page, who is also a distinguished sustainability scholar in ASU's Julie Ann Wrigley Global Institute of Sustainability. “This has been a major unanswered question in developmental biology for more than a century.”

The finding is likely to allow more detailed analysis of the interplay of genes and nutrition that drives the selection of queens from worker bees.  

Queen bees differ physically from their sterile sister workers, with a much larger body and ovaries that are needed for her prime responsibility in life — to be tended to just so to produce all the future offspring in the hive. As such, future queens are fed a bee delectable, sugar-rich “royal jelly” from the time they emerge as larvae — while future workers receive relatively sugar-poor “worker jelly.” But the degree to which diet alone determines the difference in gonadal size between queen and worker has been unclear.

To explore the genetic influences on gonad size, the authors first showed that reduced sugar had no effect on male gonad size, indicating that diet isn’t the sole influence. Next, using CRISPR, they knocked out the so-called feminizer gene in early worker larvae.

With the feminizer gene turned off by CRISPR, they found that a low-sugar diet had no effect on gonad size. In fact, their gonad size was similar to those typically found in male drones. The authors conclude that the feminizer gene must be switched on not only to produce ovaries but also to permit nutrient level to affect gonad size.

“Because of the ability to rapidly screen mutations in honey bees allowed by gene editing, this study is likely to set the stage for much more extensive investigations of the role of individual genes and gene pathways in immune defense and behavioral and developmental control,” Beye said.

These results will spur further work to determine if the same gene is needed to allow development of large ovaries in future queens.

March 11, 2019

February 28, 2019


Contact: Kami Capener (Hoeven) 202-224-8185

Shannon Beckham (Bennet) 202-740-3158



Bipartisan Legislation Would Ensure ELD, HOS Reforms Work in Real-World Conditions


WASHINGTON – Senators John Hoeven (R-N.D.) and Michael Bennet (D-Colo.) today reintroduced the Modernizing Agricultural Transportation Act, bipartisan legislation to reform the Hours of Service (HOS) and Electronic Logging Device (ELD) regulations at the U.S. Department of Transportation (DOT). Further, the bill would delay enforcement of the ELD rule until the required reforms are formally proposed by the Transportation Secretary.


“Livestock haulers need a permanent solution to the HOS and ELD rules that provides flexibility while also ensuring road safety and the humane transportation of animals,” said Senator Hoeven. “We’ve worked hard to secure regulatory relief under these rules, including the 150 air-mile agriculture exemption and the flexibility the FMCSA provided for all commercial drivers last fall. Our legislation builds on these past efforts, putting the ELD rule on hold and helping ensure the DOT advances reforms that will work in the real world.”


“Providing farmers and ranchers a seat at the table will lead to more sensible rules around the transportation of agricultural goods,” said Senator Bennet. “It is important that we maintain safe roads, while also recognizing the unique flexibility needed to move Colorado’s agricultural products to market.”


Specifically, the Hoeven-Bennet bill would establish a working group at DOT to identify obstacles to the safe, humane and market-efficient transport of agricultural commodities, including livestock, and, within one year of the group’s establishment, develop guidelines for regulatory or legislative action to improve the transportation of these commodities. The working group will be comprised of representatives from the transportation and agriculture industries, transportation safety representatives and the U.S. Department of Agriculture, and is required to consider:


  • The impact, incompatibilities and other challenges and concerns of existing HOS rules and ELD rules under the Federal Motor Carrier Safety Administration (FMCSA) on the commercial transport of livestock, insects and agricultural commodities.

  • Initiatives and regulatory changes that maintain and protect highway safety and allow for the safe, efficient and productive marketplace transport of livestock, insects and agricultural commodities.

  • Other related issues that the Transportation Secretary considers appropriate.


Within 120 days of receiving the working group’s report, the Transportation Secretary must propose regulatory changes to the HOS and ELD regulations, taking into account the findings and recommendations of the working group.


In addition to Hoeven and Bennet, the legislation introduced today is cosponsored by Senators Steve Daines (R-Mont.), Michael Rounds (R-S.D.), Tina Smith (D-Minn.), Mike Crapo (R-Idaho), James Risch (R-Idaho), Doug Jones (D-Ala.), Joni Ernst (R-Iowa), Cindy Hyde-Smith (R-Mo.) and Jon Tester (D-Mont.).


The Modernizing Agricultural Transportation Act is supported by the National Pork Producers Council (NPPC), National Cattlemen’s Beef Association (NCBA), United States Cattlemen’s Association (USCA), Livestock Marketing Association (LMA), American Farm Bureau Federation (AFBF), the American Honey Producers Association (AHPA) and the Rocky Mountain Farmer’s Union (RMFU). A summary of the Hoeven-Bennet legislation can be found here, and industry statements of support can be found here. The full text of the bill is available here.

Clarification on HopGuard II and Bee Health

By Fabiana Ahumada, Business Manager, BetaTec Hop Products, Inc.


This article is to clarify information that was recently presented in relation to HopGuard®, BetaTec’s natural miticide for Varroa mite control.  In January, the 50th Annual American Honey Producers Association Conference included a presentation titled Confirmation Bias… It Happens to All of Us that included discussion of several miticides currently on the market, including HopGuard.  Unfortunately, we believe that the information presented about HopGuard was incomplete and therefore misleading to an audience interested in using acaricides in their field colonies.  HopGuard is not only highly effective against Varroa mites, but very safe for bees, honey, and the environment when used at the recommended dosage rate in field colonies.



The above-referenced presentation presented some results from the study Toxicity of Selected Acaricides to Honey Bees (Apis mellifera) and Varroa (Varroa destructor Anderson and Trueman) and Their Use in Controlling Varroa within Honey Bee Colonies, 9 May 2018.  The presentation included a graph with results from a laboratory-based study where a “full dose” of HopGuard resulted in a high mortality rate of both Varroa mites and bees.  However, this graph illustrated only a small part of the study’s results and does not reflect the true safety of HopGuard in bee hives.  


Laboratory-Caged Conditions

The cited academic article indeed shows that under a laboratory-caged condition, a “full dose” of HopGuard induced high bee mortality.  However, because this laboratory trial used a cage and group of bees much smaller than a typical colony, the authors used only a partial HopGuard strip (even in what they call their “full dose” treatment group), and it is unclear how they determined the size of this partial strip.  BetaTec makes no claims that the application of HopGuard can be scaled down proportionately, and only recommends that the product be used as instructed on its packaging (i.e. 1 strip per 5 frames of bees or 2 strips per 10 frames of bees).


Additionally, the article explains that cutting the HopGuard dosage in half (still in the laboratory-caged testing) drastically reduced bee mortality, while maintaining a desirable rate of Varroa mortality.  The authors state: 


Nevertheless, the HopGuard was an efficacious acaricide that killed >90% of the mites, and it remained equally efficacious after halving the full test dose.  This reduced rate of the HopGuard kept the bee mortality to an acceptable level, just slightly above the control bee mortality.  Therefore, we propose that acaricide treatments, including HopGuard, that are applied at doses that cause >70% mite mortality, with less than 30% bee kill, should be considered as mite selective and acceptable for mite management.


This supports our belief that the high bee mortality rate in the “full dose” treatment was due to a disproportionately high dosage level for the small number of bees in the study, and not due to any inherent characteristics of HopGuard itself.


Field Testing

Furthermore, and more importantly, the study results differed when testing the acaricides in honeybee colonies in the field.  When discussing the effectiveness of HopGuard in the field test, the authors state:


Throughout the season, all of the treated and control colonies developed normally and remained strong without any mass deaths occurring among worker bees or queens.  It was noteworthy that the efficacy of controlling the Varroa in cages corresponded to the efficacy of the Varroa control in the colonies.


In the field, when HopGuard was applied as directed on the packaging, bees remained at a safe and healthy level.



The presentation at the recent AHPA conference, presented information from an academic article that described one lab-based study in which HopGuard had a high bee mortality rate.  However, the rest of the article demonstrates that when HopGuard is properly dossed at the instructed rate, bee mortality is not a concern. 


Numerous bee colony field studies have proven the safety and effectiveness of HopGuard in controlling Varroa mites.  This natural treatment is safe to use any time of the year, even during honey flow, without disrupting foraging behavior or tainting the honey.  BetaTec stands behind its HopGuard product as well as the safety of bees, beekeepers, and the environment.  If you have any questions or would like more information, please contact us at


We would like to thank AHPA for the opportunity to publish this article.

Pesticide Exposure Changes Bees’ Genes

By Olivia Rosane

Mar. 08, 2019 07:53AM EST

A new study has found that exposure to certain pesticides can alter bees' genes, leading researchers to call for tougher regulations on the widely-used chemicals.


The study, published Wednesday in Molecular Ecology, looked at the impact of two neonicotinoid pesticides on bumblebee populations and found that they impacted genes involved in a variety of important biological processes.


"Governments had approved what they thought were 'safe' levels but pesticides intoxicate many pollinators, reducing their dexterity and cognition and ultimately survival," lead study author Dr. Yannick Wurm of Queen Mary's School of Biological and Chemical Sciences said in a press release. "This is a major risk because pollinators are declining worldwide yet are essential for maintaining the stability of the ecosystem and for pollinating crops."

Previous studies had looked at the impact of neonicotinoids on the behaviors of bees, showing that exposure impaired their ability to forage and develop colonies. But this study, conducted by researchers at Queen Mary University of London and Imperial College London, focused on how those impacts occur on the molecular level.


"Our work reveals that neurotoxic pesticides not only directly target the cells of the nervous system, but also indirectly affect the normal activity of the exposed organism's genes," study author Dr. Richard Gill of the Department of Life Sciences at Imperial College London said in a press release.


The researchers studied the impact of realistic concentrations of two neonicotinoids on bumblebees: clothianidin and imidacloprid. They found that clothianidin had a stronger effect and that queens and workers were impacted differently. Clothianidin exposure altered the activity levels of 55 worker genes, making 31 more active and the rest less active.


"This could indicate that their bodies are reorienting resources to try to detoxify, which the researchers suspect is what some of the genes are doing. For other genes, the changes could represent the intermediate effects of intoxication that lead to affected behavior," the Queen Mary press release explained.


For queens, 17 genes saw their activity levels altered, with 16 becoming more active.

While neonicotinoids were banned in the EU in 2018, they are still widely used elsewhere.

The researchers thought that the study mechanism could be used to assess the specific impact of pesticides on other pollinators.


"We examined the effects of two pesticides on one species of bumblebee. But hundreds of pesticides are authorised, and their effects are likely to substantially differ across the 200,000 pollinating insect species which also include other bees, wasps, flies, moths, and butterflies," first study author Dr. Joe Colgan of Queen Mary University said.


The study comes about a month after another study warned that insect populations around the world are in grave danger, and the widespread use of pesticides is one of the main reasons why.

Tracking pollen with quantum dots

Date: February 14, 2019

Source: Stellenbosch University

Summary: Most plant species on earth are reliant on insects for pollination, including more than 30% of the food crops we eat. With insects facing rapid global decline, it is crucial that scientists understand which insects are important pollinators of different plants--this starts with tracking pollen.

A pollination biologist from Stellenbosch University in South Africa is using quantum dots to track the fate of individual pollen grains. This is breaking new ground in a field of research that has been hampered by the lack of a universal method to track pollen for over a century.

In an article published in the journal Methods in Ecology and Evolution this week, Dr Corneile Minnaar describes this novel method, which will enable pollination biologists to track the whole pollination process from the first visit by a pollinator to its endpoint -- either successfully transferred to another flower's stigma or lost along the way.

Despite over two hundred years of detailed research on pollination, Minnaar says, researchers do not know for sure where most of the microscopically tiny pollen grains actually land up once they leave flowers: "Plants produce massive amounts of pollen, but it looks like more than 90% of it never reaches stigmas. For the tiny fraction of pollen grains that make their way to stigmas, the journey is often unclear -- which pollinators transferred the grains and from where?"

Starting in 2015, Minnaar decided to tread where many others have thus far failed, and took up the challenge through his PhD research in the Department of Botany and Zoology at Stellenbosch University (SU).

This bee was caught after it visited a flower of which the pollen grains were labelled with quantum dots. Under the microscope one can see where the pollen was placed, and actually determine which insects carry the most pollen from which flower. Credit: Corneile Minnaar

"Most plant species on earth are reliant on insects for pollination, including more than 30% of the food crops we eat. With insects facing rapid global decline, it is crucial that we understand which insects are important pollinators of different plants -- this starts with tracking pollen," he explains.

He came upon the idea for a pollen-tracking method after reading an article on the use of quantum dots to track cancer cells in rats. Quantum dots are semiconductor nanocrystals that are so small, they behave like artificial atoms. When exposed to UV light, they emit extremely bright light in a range of possible colours. In the case of pollen grains, he figured out that quantum dots with "fat-loving" (lipophilic) ligands would theoretically stick to the fatty outer layer of pollen grains, called pollenkitt, and the glowing colours of the quantum dots can then be used to uniquely "label" pollen grains to see where they end up.

The next step was to find a cost-effective way to view the fluorescing pollen grains under a field dissection microscope. At that stage Minnaar was still using a toy pen from a family restaurant with a little UV LED light that he borrowed from one of his professors.

"I decided to design a fluorescence box that can fit under a dissection microscope. And, because I wanted people to use this method, I designed a box that can easily be 3D-printed at a cost of about R5,000, including the required electronic components." (view video at

So far, the method and excitation box have proven itself as an easy and relatively inexpensive method to track individual pollen grains: "I've done studies where I caught the insects after they have visited the plant with quantum-dot labelled anthers, and you can see where the pollen is placed, and which insects actually carry more or less pollen."

But the post-labelling part of the work still requires hours and hours of painstaking counting and checking: "I think I've probably counted more than a hundred thousand pollen grains these last three years," he laughs.

As a postdoctoral fellow in the research group of Prof Bruce Anderson in the Department of Botany and Zoology at Stellenbosch University, Minnaar will continue to use the method to investigate the many unanswered questions in this field.

Story Source:

Materials provided by Stellenbosch University. Note: Content may be edited for style and length.

Journal Reference:

Corneile Minnaar, Bruce Anderson. Using quantum dots as pollen labels to track the fates of individual pollen grains. Methods in Ecology and Evolution, 2019; DOI: 10.1111/2041-210X.13155

Flowers can hear buzzing bees—and it makes their nectar sweeter

“I’d like people to understand that hearing is not only for ears.”

By Michelle Z. Donahue

PUBLISHED January 15, 2019


Even on the quietest days, the world is full of sounds: birds chirping, wind rustling through trees, and insects humming about their business. The ears of both predator and prey are attuned to one another’s presence.


Sound is so elemental to life and survival that it prompted Tel Aviv University researcher Lilach Hadany to ask: What if it wasn’t just animals that could sense sound—what if plants could, too? The first experiments to test this hypothesis, published recently on the pre-print server bioRxiv, suggest that in at least one case, plants can hear, and it confers a real evolutionary advantage.

Hadany’s team looked at evening primroses (Oenothera drummondii) and found that within minutes of sensing vibrations from pollinators’ wings, the plants temporarily increased the concentration of sugar in their flowers’ nectar. In effect, the flowers themselves served as ears, picking up the specific frequencies of bees’ wings while tuning out irrelevant sounds like wind.


The sweetest sound

As an evolutionary theoretician, Hadany says her question was prompted by the realization that sounds are a ubiquitous natural resource—one that plants would be wasting if they didn’t take advantage of it as animals do. If plants had a way of hearing and responding to sound, she figured, it could help them survive and pass on their genetic legacy.


Since pollination is key to plant reproduction, her team started by investigating flowers. Evening primrose, which grows wild on the beaches and in parks around Tel Aviv, emerged as a good candidate, since it has a long bloom time and produces measurable quantities of nectar. To test the primroses in the lab, Hadany’s team exposed plants to five sound treatments: silence, recordings of a honeybee from four inches away, and computer-generated sounds in low, intermediate, and high frequencies. Plants given the silent treatment—placed under vibration-blocking glass jars—had no significant increase in nectar sugar concentration. The same went for plants exposed to high-frequency (158 to 160 kilohertz) and intermediate-frequency (34 to 35 kilohertz) sounds.


But for plants exposed to playbacks of bee sounds (0.2 to 0.5 kilohertz) and similarly low-frequency sounds (0.05 to 1 kilohertz), the final analysis revealed an unmistakable response. Within three minutes of exposure to these recordings, sugar concentration in the plants increased from between 12 and 17 percent to 20 percent.


A sweeter treat for pollinators, their theory goes, may draw in more insects, potentially increasing the chances of successful cross-pollination. Indeed, in field observations, researchers found that pollinators were more than nine times more common around plants another pollinator had visited within the previous six minutes.


“We were quite surprised when we found out that it actually worked,” Hadany says. “But after repeating it in other situations, in different seasons, and with plants grown both indoors and outdoors, we feel very confident in the result.”


Flowers for ears

As the team thought about how sound works, via the transmission and interpretation of vibrations, the role of the flowers became even more intriguing. Though blossoms vary widely in shape and size, a good many are concave or bowl-shaped. This makes them perfect for receiving and amplifying sound waves, much like a satellite dish.


To test the vibrational effects of each sound frequency test group, Hadany and her co-author Marine Veits, then a graduate student in Hadany’s lab, put the evening primrose flowers under a machine called a laser vibrometer, which measures minute movements. The team then compared the flowers’ vibrations with those from each of the sound treatments. “This specific flower is bowl- shaped, so acoustically speaking, it makes sense that this kind of structure would vibrate and increase the vibration within itself,” Veits says.


And indeed it did, at least for the pollinators’ frequencies. Hadany says it was exciting to see the vibrations of the flower match up with the wavelengths of the bee recording.


“You immediately see that it works,” she says.


To confirm that the flower was the responsible structure, the team also ran tests on flowers that had one or more petals removed. Those flowers failed to resonate with either of the low-frequency sounds.


What else plants can hear

Hadany acknowledges that there are many, many questions remaining about this newfound ability of plants to respond to sound. Are some “ears” better for certain frequencies than others? And why does the evening primrose make its nectar so much sweeter when bees are known to be able to detect changes in sugar concentration as small as 1 to 3 percent?


Also, could this ability confer other advantages beyond nectar production and pollination? Hadany posits that perhaps plants alert one another to the sound of herbivores mowing down their neighbors. Or maybe they can generate sounds that attract the animals involved in dispersing that plant’s seeds.


“We have to take into account that flowers have evolved with pollinators for a very long time,” Hadany says. “They are living entities, and they, too, need to survive in the world. It’s important for them to be able to sense their environment—especially if they cannot go anywhere.”


This single study has cracked open an entirely new field of scientific research, which Hadany calls phytoacoustics.


Veits wants to know more about the underlying mechanisms behind the phenomenon the research team observed. For instance, what molecular or mechanical processes are driving the vibration and nectar response? She also hopes the work will affirm the idea that it doesn’t always take a traditional sense organ to perceive the world.


“Some people may think, How can [plants] hear or smell?” Veits says. “I’d like people to understand that hearing is not only for ears.”


Richard Karban, an expert in interactions between plants and their pests at the University of California Davis, has questions of his own, in particular, about the evolutionary advantages of plants’ responses to sound.


“It may be possible that plants are able to chemically sense their neighbors, and to evaluate whether or not other plants around them are fertilized,” he says. “There’s no evidence that things like that are going on, but [this study] has done the first step.”

American Honey
Producers Association

  • Facebook Social Icon

Cassie Cox
Executive Secretary
PO Box 435
Mendon, UT 84325