Latest Research on Bee Attrition: Why We Need to Act and What We Need to Do

Honeybee disorders and high colony losses are serious global phenomena and this threatens our food system. The latest evidence suggests that there is an interrelationship between pesticides, fungicides, and parasites. In addition to the agricultural impacts of bee attrition, there are pervasive ecosystem implications that extend far beyond croplands. The study, Single pollinator species losses reduce floral fidelity and plant reproductive function, published in the Proceedings of the National Academy of Sciences, shows the wider consequences of bee losses on plant reproduction as well as on overall ecosystem health.

Bees are Essential to Agriculture

Bees are well known for providing honey and wax, but as pollinators, they are also indispensable to agriculture.  Bees are an essential part of food production and according to some estimates, they are responsible for one of every three bites of food we eat. The economic value of pollination services from honeybees alone are estimated at $14 billion in the U.S. and hundreds of millions in Canada.

Bees are nature’s best pollinators because, unlike some other species, they seek out both nectar and pollen. Bees fertilize crops ranging from almonds to zucchini. They are especially important to crops like watermelons, pumpkins, cucumbers, and cranberries and farmers who grow apples and blueberries are almost entirely dependent on bees for pollination.

Die-offs & Colony Weakness

Early explanations for disintegrating bee numbers were attributed to what is known as “colony collapse disorder.” In this theory, colonies that seemed pretty healthy suddenly collapsed as bees abandoned their hives. Now it appears that bee colonies are just getting smaller and weaker. In bee colonies, size matters as more bees make it easier to generate heat and rear their brood, heat is also required for bees to fly.

A new survey of America’s beekeepers indicates that almost a third of U.S. honeybee colonies did not make it through last winter. This is a repeat of massive bee die-offs that have been occurring almost every year since the U.S. Department of Agriculture began this annual survey in 2007.

Successive years of massive bee die-offs are a serious concern. Commercial beekeepers can afford to lose only about 15 percent of their colonies each year. With numbers more than twice the acceptable limit, the future of the commercial bee industry is in doubt and as a consequence, crop production. In places like West Bath, Maine, the number of bees is already so low that there may not be enough to pollinate major crops.

There have been a number of theories put forth to explain why bees are being decimated. Some of the more prominent theories include pesticides, fungicides, parasites and poor nutrition.

Pesticides and fungicides

A recent study conducted by researchers at the University of Maryland and U.S. Department of Agriculture (USDA) found that pollen collected by honeybees was contaminated with a toxic mix of pesticides and fungicides.

As reported in the study, Recent research is uncovering diverse sub-lethal effects of pesticides on bees. Even at low levels, pesticides and fungicides have been linked to foraging and navigational disruptions, immune suppression and learning/memory disorders in bees.

Researchers found 35 different pesticides in pollen including oxadiazines, neonicotinoids, carbamates, cyclodienes, formamidines, organophosphates, and pyrethroids. Pollen samples contained an average of nine different agricultural pesticides and fungicides and as many as 21 in one case. Researchers most frequently found fungicides in pollen samples, particularly chlorothalonil, which is a broad-spectrum fungicide ubiquitously used on apples and other crops.

One particular class of pesticides called neonicotinoids is garnering a lot of attention. Water-soluble pesticides such as neonicotinoids are a real danger because they are systemic. This class of pesticide is readily absorbed by plant roots and transported throughout the plant’s vascular system to other portions of the plant, including their pollen and nectar. Residues remain in the plant for their lifetime, continually endangering any pollinators that forage or pollinate these contaminated plants.

An international team of scientists led by Holland’s Utrecht University concluded that”Large scale prophylaxic use in agriculture, their high persistence in soil and water, and their uptake by plants and translocation to flowers, neonicotinoids put pollinator services at risk.”

Neonicotinoids are also used in planting corn and some other crops. Neonicotinoids are used to coat corn seeds and new seeders disperse the pesticide into the air.  There is considerable anecdotal evidence pointing to the correlation between the planting of corn and bee death. Here are three examples from Ontario, Canada.

Beekeeper Dave Schuit lost 600 hives this year and a total of 37 million bees.  As explained by Schuit, “once the corn started to get planted our bees died by the millions.”

Schuit is hardly the only one suffering bee loses directly after corn is planted. At the farm of Gary Kenny, eight of the 10 hives died this spring just after corn was planted in neighboring fields. Similar occurrences were also observed near Gulph Ontario.

A Pest Management Regulatory Agency investigation confirmed that corn seeds treated with clothianidin or thiamethoxam, “contributed to the majority of the bee mortalities.”  Researchers found pesticides in every single pollen sample, even those that were collected from nearby wildflowers that were not sprayed. “The air seeders are the problem,” said Ontario Federation of Agriculture director Paul Wettlaufer.

According to research from American Purdue University, “Bees exhibited neurotoxic symptoms, analysis of dead bees revealed traces of thiamethoxam/clothianidin in each case.” They concluded that, “Seed treatments of field crops (primarily corn) are the only major source of these compounds.”

The adverse impact of neonicotinoids on bees has been observed around the world. An extensive overview of the major studies showing the effects of neonicotinoids on pollinator health can be found on Beyond Pesticides’ What the Science Shows.

Susceptibility to Parasites

Some research suggests that there is a relationship between pesticides, fungacides and parasites. One of the parasites singled out is Varroa Mite, but more recent research suggests that pesticides may make the bees more vulnerable to a parasite called Nosema Ceranae. The Maryland report links eight pesticides as increasing the risk of Nosema gut parasite infestations.

Lead researcher Jeff Pettis, PhD at the Bee Research Laboratory in Beltsville, MD explained that honeybees that were fed pollen containing the fungicide chlorothalonil and collected at the hive entrance were almost three times more likely to become infected when exposed to the parasite Nosema, compared with control bees, which were not fed contaminated pollen.

The newest USDA research adds to the growing body of evidence that shows pesticide exposure weakens honeybees’ immune systems making them more susceptible to parasites and pathogens. It appears that the toxins make the bees more vulnerable to parasites, which is now believed to be the cause of colony collapse disorder.

While pesticides and fungicides are most often studied in isolation, the problem may be most likely to occur when used in combination. According to the Maryland study’s lead author, Dennis vanEngelsdorp, quoted in the online news outlet Quartz, “It’s a lot more complicated than just one product, which means of course the solution does not lie in just banning one class of product.”

Poor Nutrition

Bees are also under threat from poor nutrition due to drought and habitat loss. These factors decrease the number of flowering plants that bees depend on for nectar and pollen. This causes malnutrition which also makes bees more susceptible to disease.

Drought, which is expected to increase due to global warming, will further decrease the number of flowering plants on which bees depend.  A recent study published in Science found half the wild bee species in the U.S. were wiped out during the 20th century and habitat loss may have figured prominently in this decline.

Home Gardening

Home gardens may also be contributing to the decline of bee populations. A recent Grist article, by John Upton cites a new report by Friends of the Earth and the Pesticide Research Institute. Their investigation revealed that more than half (7 of 13) of supposedly “bee-friendly” nursery plants sold at major hardware stores are contaminated with neonicotinoid pesticides. (Nurseries commonly apply neonicotinoids as soil injections, granular or liquid soil treatments, foliar sprays, and seed treatments.)

What is Being Done

Friends of the Earth, Pesticide Action Network, The Xerces Society, and other nonprofits are sending letters and signing petitions to major garden retailers asking them to stop selling plants that have been pre-treated with pesticides.

Many people and businesses are mobilizing to try to raise awareness about the serious threats faced by bees. One such initiative comes from Ted Dennard who is a lifelong beekeeper and owner of a Savannah Bee Company. He has started an awareness campaign called The Bee Cause Project, this non-profit teaches children the ABCs of honeybees, beekeeping, and the importance of both. Dennard is also behind the “God Save the Queen (bee)” campaign in his retail outlets.

In June, a Whole Food Market store in Rhode Island pulled more than half of the produce department’s products off of shelves to show what the food supply would look like without bees. This campaign sought to graphically illustrate how major declines in honeybee populations threaten the availability of many fresh ingredients.

Others are taking legal action. On March 21, 2013, Beyond Pesticides joined beekeepers, environmental and consumer groups in filing a lawsuit in Federal District Court against the EPA for its failure to protect pollinators from dangerous pesticides.

New EPA guidelines will prohibit the use of some neonicotinoid pesticides when bees are present, and include information on routes of exposure and spray drift precautions.

Although Europe is planning to ban some uses of pesticides harmful to bees, agrochemical company Syngenta has indicated that it may initiate a legal challenge to stop the EU’s plan to limit the use of pesticides.

What Else Can Be Done?

One of the most obvious things individuals can do is stop using pesticides and fungicides. People can also grow more flowering plants. The best way to ensure that they are bee-friendly is to buy organic plants.  We can also end the use of air seeders where pesticides are present. People can also work to spread the word in their local communities and call for a ban on the pesticides and fungicides that are known to be detrimental to bees.

Federal legislation may be the most effective way to address the problem. In the middle of July, bee protection legislation was introduced by Reps. John Conyers (D-MI) and Earl Blumenauer (D-OR).  The Save America’s Pollinators Act, (H.R. 2692) calls upon the EPA to suspend the use of neonicotinoids and to conduct a full review of scientific research before allowing the entry of other neonicotinoids into the market.

Sadly, without widespread support from voters, it is unlikely that the bill will win approval from the GOP that rules the House. Click here to tell your representative in Congress to save America’s bees.

Image credit: Rick and Brenda Beerhorst, courtesy Flickr


Richard Matthews
Richard Matthews
Richard Matthews is a consultant, eco-entrepreneur, sustainable investor, and writer. He is the owner of THE GREEN MARKET, one of the Web’s most comprehensive resources on the business of the environment. He is also the author of numerous articles on sustainable positioning, green investing, enviro-politics, and eco-economics.

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