Bee Alert: Is a Controversial Herbicide Harming Honeybees?

Yale Environment 360 By Michael Balter May 7, 2019

A honeybee pollinates a blossom in an almond orchard in McFarland, California. DAVID KOSLING/ USDA

A honeybee pollinates a blossom in an almond orchard in McFarland, California. DAVID KOSLING/USDA

Recent court cases have focused on the possible effects of glyphosate, found in Monsanto’s Roundup, on humans. But researchers are now investigating whether this commonly used herbicide could also be having adverse effects on the health and behavior of honeybees.

Is one of the world’s most widely used herbicides a danger not only to annoying weeds, but also to honeybees? While debates rage over whether certain powerful insecticides are responsible for so-called colony collapse disorder — or even whether bee populations are declining at all — recent research suggests that glyphosate, the active ingredient in weed killers such as Monsanto’s Roundup, could be having subtle effects on bee health.

Glyphosate has been in the news in recent months, but not for its possible harm to bees. Rather, some studies have suggested an association between exposure to glyphosate and higher risk of non-Hodgkin lymphoma (NHL), a cancer of the white blood cells. Glyphosate garnered headlines last August when a jury in California awarded groundskeeper DeWayne Johnson a massive judgement against Monsanto’s parent company, the German pharmaceutical giant Bayer. Johnson, along with more than 13,000 other plaintiffs, alleges that glyphosate caused his case of NHL.

But concerns about glyphosate are not limited to humans. Researchers have been accumulating evidence that glyphosphate may also be having deleterious effects on the environment and be harmful to fish, crustaceans, and amphibians, as well as to beneficial bacteria and other microorganisms in soil and water.

A University of Texas study reported evidence that glyphosate disrupts microorganisms in the guts of bees.

In recent years, a number of studies have concluded that glyphosate could also be hazardous to bees. Although the herbicide does not appear as toxic to bees as some other pesticides (notably neurotoxins known as neonicotinoids), researchers have found that glyphosate may impact bees in more subtle ways — for example, impeding the growth of bee larvae, diminishing bees’ navigational skills, altering their foraging behavior, or even disrupting their gut microorganisms, known as the microbiome.

The research is controversial because defenders of glyphosate use have long argued that it is benign in the environment. The herbicide is uniquely designed to target an enzyme that plants need to grow. That enzyme is essential to the so-called shikimate pathway, a metabolic process required for the production of certain essential amino acids and other plant compounds. However, the shikimate pathway is also used by some bacteria and other microorganisms, raising the possibility that glyphosate could have widespread and unexpected effects on a variety of natural organisms.

In a September study in the Proceedings of the National Academy of Sciences, Nancy Moran, an evolutionary biologist and entomologist at the University of Texas, Austin, and her coworkers found evidence that glyphosate disrupts microorganisms found in bees’ guts.

Monsanto's Roundup at a store in San Rafael, California. The product's manufacturer maintains that glyphosate is safe when used as directed.JOSH EDELSON/AFP/ GETTY IMAGES

Monsanto's Roundup at a store in San Rafael, California. The product's manufacturer maintains that glyphosate is safe when used as directed.JOSH EDELSON/AFP/GETTY IMAGES

Mature bees have eight dominant gut bacterial species. Those strains are responsible for such benefits as promoting weight gain and providing resistance to harmful pathogens. The University of Texas team found almost all of them declined when the bees were exposed to concentrations of glyphosate commonly found in the environment. Young worker bees exposed to glyphosate were more susceptible to dying from infections. Moreover, the gut bacteria were more sensitive to the effects of glyphosate if the bacteria possessed an enzyme known to play a key role in the shikimate pathway.

Bayer disputes research findings suggesting Roundup or glyphosate is hazardous to bees. Utz Klages, Bayer’s head of external communications, says the “good news is that honeybee colonies are not in decline and rumors of their demise are greatly exaggerated.” Klages notes that regulatory authorities in a number of countries, including the United States, Canada, and the nations of the European Union, “have determined that glyphosate is safe when used as directed.”

A number of studies have suggested that glyphosate is not highly toxic to bees, including research performed by Monsanto and several other agrochemical companies. That research considered the “realistic worst-case” exposures to the herbicide and found no significant effect on bee mortality. Similarly, a series of studies led by Yu Cheng Zhu, a research entomologist at the U.S. Department of Agriculture, concluded that glyphosate did not seem to kill bees outright. “We did not find an unusual number of dead bees after spraying a bee yard with Roundup a few times each year,” Zhu said.

Scientists have found that glyphosate appears to interfere with the growth and survival of honeybee larvae.

But Walter Farina, a researcher at the University of Buenos Aires in Argentina, says that the very fact that glyphosate is not immediately toxic to bees facilitates the harm it does. “Since glyphosate does not cause lethal effects, it can enter the colony and [be] assimilated by the younger individuals,” Farina says. “The negative effects of [glyphosate] are worse for younger bees, promoting an increased disorganization of the collective task within the hives.”

Farina and his team have looked at some of these effects in Argentina, where glyphosate is intensively used in agriculture. In a 2014 study, published in The Journal of Experimental Biology, they found that the “appetitive behavior” of honeybees — including how well they could detect sucrose and their ability to learn and remember where food sources were located — was significantly diminished after exposure to doses of glyphosate commonly found in farmlands.

In a second study, published in 2015 in the same journal, Farina’s team used harmonic radar to track how long it took honeybees to find their way back to their hives. They found that exposure to relatively low doses of glyphosate appeared to hinder the bees’ ability to navigate back to the hive, and concluded that glyphosate “impairs the cognitive capacities needed to retrieve and integrate spatial information for a successful return.”

A farmer in Argentina, where glyphosate is used intensively, sprays a soybean field in Entre Rios province in February 2018. PABLO AHARONIAN/AFP/ GETTY IMAGES

A farmer in Argentina, where glyphosate is used intensively, sprays a soybean field in Entre Rios province in February 2018. PABLO AHARONIAN/AFP/GETTY IMAGES

In other research, scientists have found that glyphosate appears to interfere with the growth and survival of honeybee larvae. For example, in a studypublished last year in the Journal of Agricultural and Food Chemistry, Pingli Dai of the Institute of Apicultural Research in Beijing, China, and his colleagues found that elevated exposures to glyphosate can lower both the weight of bee larvae and the larval survival rate. This study also showed that glyphosate markedly decreased the diversity and richness of bacteria in the larvae’s intestines, indicators of reduced resilience.

As concerns about how glyphosate may be affecting honeybees mount, researchers are getting a boost from funding agencies that see this as an important research avenue. In March, the National Science Foundation awarded nearly $1 million in grant money to researchers at Virginia Tech and Eastern Washington University to further study the honeybee microbiome.

Meanwhile, Moran, at the University of Texas, says her lab has done follow-up confirmatory experiments using antibiotics to target the honeybee gut bacteria, with similar results on bee mortality as in the previous experiments. She emphasizes that these results have little to say so far about how important a factor glyphosate might be in the declines in bee populations. “We have to say that we don’t know at this point,” she says. “Our results suggest that it is worth studying further, which is what we are doing, and hope others will do also.”

https://e360.yale.edu/features/bee-alert-is-a-controversial-herbicide-harming-honeybees

Not Just Bumble and Honey: Ground Nesting Bees Impaired by Neonicotinoid Exposure

Beyond Pesticides March 19, 2019

Honey bees and neonicotinoids.jpg

(Beyond Pesticides, March 19, 2019) Research is beginning to explain how systemic neonicotinoid insecticides affect often overlooked species of ground nesting bees. While much of the current scientific literature has focused on the impacts of pesticides to bumblebees and honey bees, a study, Chronic contact with realistic soil concentrations of imidacloprid affects the mass, immature development speed, and adult longevity of solitary bees, recently published in Scientific Reports, confirms that wild, soil-dwelling bees are at similar risk. As policy makers consider ways to protect pollinators, this research finds that uncontaminated soil is an important aspect of ensuring the health of wild, native bees.

“This is an important piece of work because it’s one of the first studies to look at realistic concentrations of pesticides that you would find in the soil as a route of exposure for bees,” said Nick Anderson, co-author of the study. “It’s a very under-explored route, especially for some of the more solitary species that nest in the ground.”

In order to study the impact of neonicotinoids on ground nesting bees, researchers used orchard mason bees and leafcutter bees as proxies, as they are easier to gather and rear in the lab, and have a similar ecology to ground nesting species. Roughly 300 bees of each species were taken into the lab as larva, and exposed every 48 hours to either 7.5, 15, or 100 ppb of the neonicotinoid imidacloprid. A control with no exposure was also established as a baseline. The authors explain that these amounts represent realistic exposure patterns that wild bees are likely to encounter in soil.

Researchers monitored the bees every day until they reached adulthood, recording longevity, development speed, and mass. Results show that male and female bees have different reactions to exposure. Female mason bees subject to the highest concentrations of imidacloprid live much shorter lives than those unexposed, while the authors had difficulty determining effects on male bees due to an equipment malfunction. Male leafcutter bees actually lived longer than control bees, but developed much faster and to a smaller size than bees not exposed to a pesticide. Female leafcutter development appeared to depend on the concentration of exposure, with the 15ppb group developing slower than other treatment levels and the 100ppb group developing two days faster than control bees.

The changes are likely a result of a hormetic response by the pollinators. This is a phenomena that results from exposure to pesticides; changes in development occur in order to compensate for energy the bee diverts into physical and biological protections from pesticide exposure. This has important implications for the long term health of ground-nesting bees. Any change in development that distracts or alters normal functioning can affect fitness in the field.

Previous research on the environmental fate of neonicotinoids shows that they have the potential to remain in soil from 200 days to as long as 19 years. This means that the type of chronic exposure tested in the current study could occur years or even a decade after an initial pesticide application. Although scientific literature on wild pollinators is limited, past research on mason bees revealed 50% reduced total offspring and a significantly male-biased offspring sex ratio.

The pollinator crisis is broader than honey and bumble bees, and extends not only to native, ground nesting bees but also butterflies and birds. The New York Times has identified the precipitous decline in insect populations over the past several decades as an insect apocalypse.

While bombastic “apocalyptic” language may be criticized for stoking panic and fear, even these warnings have been generally ignored by many policy makers, begging the question of what it will actually take in order to get action on this critical issue. We need to protect not only honey bees, but the wide diversity of native pollinators in order to maintain agricultural production, floral resources, and other ecosystem services that enable our environment, and ultimately human civilization to thrive.

U.S. Representatives Earl Blumenauer, Jim McGovern, and the 33 current cosponsors of the Saving America’s Pollinators Act are listening to these warnings, and have introduced legislation that would substantive address the threats pesticides pose to pollinators. But in order for change to happen, we need a significant outpouring of public support in favor of this proposal. Take action today by urging your member of Congress to cosponsor SAPA. And if you’re also interested in working on this issue in your state or local community, contact Beyond Pesticides at info@beyondpesticides.org or 202-543-5450.

All unattributed positions and opinions in this piece are those of Beyond Pesticides.

Source: University of Illinois Press ReleaseScientific Reports (peer reviewed journal)

https://beyondpesticides.org/dailynewsblog/2019/03/not-just-bumble-and-honey-ground-nesting-bees-impaired-by-neonicotinoid-exposure/

Improved Regulation Needed As Pesticides Found to Affect Genes in Bees

EurekAlert From: Queen Mary University of London March 6, 2019

Bumblebee Colony Credit: TJ Colgan

Bumblebee Colony Credit: TJ Colgan

Scientists are urging for improved regulation on pesticides after finding that they affect genes in bumblebees, according to research led by Queen Mary University of London in collaboration with Imperial College London.

For the first time, researchers applied a biomedically inspired approach to examine changes in the 12,000 genes that make up bumblebee workers and queens after pesticide exposure.

The study, published in Molecular Ecology, shows that genes which may be involved in a broad range of biological processes are affected.

They also found that queens and workers respond differently to pesticide exposure and that one pesticide they tested had much stronger effects than the other did.

Other recent studies, including previous work by the authors, have revealed that exposure even to low doses of these neurotoxic pesticides is detrimental to colony function and survival as it impairs bee behaviours including the ability to obtain pollen and nectar from flowers and the ability to locate their nests.

This new approach provides high-resolution information about what is happening at a molecular level inside the bodies of the bumblebees.

Some of these changes in gene activity may represent the mechanisms that link intoxification to impaired behaviour.

Lead author of the study Dr Yannick Wurm, from Queen Mary University of London, said: "Governments had approved what they thought were 'safe' levels but pesticides intoxicate many pollinators, reducing their dexterity and cognition and ultimately survival. This is a major risk because pollinators are declining worldwide yet are essential for maintaining the stability of the ecosystem and for pollinating crops.

"While newer pesticide evaluation aims to consider the impact on behaviour, our work demonstrates a highly sensitive approach that can dramatically improve how we evaluate the effects of pesticides."

The researchers exposed colonies of bumblebees to either clothianidin or imidacloprid at field-realistic concentrations while controlling for factors including colony social environment and worker age.

They found clothianidin had much stronger effects than imidacloprid - both of which are in the category of 'neonicotinoid' pesticides and both of which are still used worldwide although they were banned in 2018 for outdoor use by the European Union.

For worker bumblebees, the activity levels of 55 genes were changed by exposure to clothianidin with 31 genes showing higher activity levels while the rest showed lower activity levels after exposure.

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 intoxification that lead to affected behaviour.

The trend differed in queen bumblebees as 17 genes had changed activity levels, with 16 of the 17 having higher activity levels after exposure to the clothianidin pesticide.

Dr Joe Colgan, first author of the study and also from Queen Mary University of London, said: "This shows that worker and queen bumblebees are differently wired and that the pesticides do not affect them in the same way. As workers and queens perform different but complementary activities essential for colony function, improving our understanding of how both types of colony member are affected by pesticides is vital for assessing the risks these chemicals pose."

The researchers believe that the approach they have demonstrated must now be applied more broadly. This will provide detailed information on how pesticides differ in the effects they have on beneficial species, and why species may differ in their susceptibility.

Dr Colgan said: "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."

Dr Wurm added: "Our work demonstrates that the type of high-resolution molecular approach that has changed the way human diseases are researched and diagnosed, can also be applied to beneficial pollinators. This approach provides an unprecedented view of how bees are being affected by pesticides and works at large scale. It can fundamentally improve how we evaluate the toxicity of chemicals we put into nature."

###

Research paper: 'Caste- and pesticide-specific effects of neonicotinoid pesticide exposure on gene expression in bumblebees'. Thomas J. Colgan, Isabel K. Fletcher, Andres N. Arce, Richard J. Gill, Ana Ramos Rodrigues, Eckart Stolle, Lars Chittka and Yannick Wurm. Molecular Ecology.

https://www.eurekalert.org/pub_releases/2019-03/qmuo-irn030519.php

Culprit Found For Honeybee Deaths In California Almond Groves

PHYS.ORG   By Misti Crane     February 4, 2019

Credit: CC0 Public Domain

Credit: CC0 Public Domain

It's about time for the annual mass migration of honeybees to California, and new research is helping lower the chances the pollinators and their offspring will die while they're visiting the West Coast.

Each winter, professional beekeepers from around the nation stack hive upon hive on trucks destined for the Golden State, where February coaxes forward the sweet-smelling, pink and white blossoms of the Central Valley's almond trees.

Almond growers rent upwards of 1.5 million colonies of honeybees a year, at a cost of around $300 million. Without the bees, there would be no almonds, and there are nowhere near enough native bees to take up the task of pollinating the trees responsible for more than 80 percent of the world's almonds. The trouble was, bees and larvae were dying while in California, and nobody was sure exactly why. The problem started in adults only, and beekeepers were most worried about loss of queens.

Then in 2014, about 80,000 colonies—about 5 percent of bees brought in for pollination—experienced adult bee deaths or a dead and deformed brood. Some entire colonies died.

With support from the Almond Board of California, an industry service agency, bee expert Reed Johnson of The Ohio State University took up the task of figuring out what was happening. Results from his earlier research had shown that some insecticides thought safe for bees were impacting larvae. Building on that, Johnson undertook a new study, newly published in the journal Insects, that details how combinations of insecticides and fungicides typically deemed individually "safe" for honeybees turn into lethal cocktails when mixed.

Johnson, an associate professor of entomology, and his study co-authors were able to identify the chemicals commonly used in the almond groves during bloom because of California's robust and detailed system for tracking pesticide applications. Then, in a laboratory in Ohio, they tested combinations of these chemicals on honeybees and larvae.

In the most extreme cases, combinations decreased the survival of larvae by more than 60 percent when compared to a control group of larvae unexposed to fungicides and insecticides.

"Fungicides, often needed for crop protection, are routinely used during almond bloom, but in many cases growers were also adding insecticides to the mix. Our research shows that some combinations are deadly to the bees, and the simplest thing is to just take the insecticide out of the equation during almond bloom," he said.

"It just doesn't make any sense to use an insecticide when you have 80 percent of the nation's honeybees sitting there exposed to it."

The recommendation is already catching on and has been promoted through a wide array of presentations by almond industry leaders, beekeepers and other experts and has been included in the Almond Board's honeybee management practices. Many almond growers are rethinking their previous practices and are backing off insecticide use during almond bloom, Johnson said.

That's good news for bees, and doesn't appear to be harming the crops either, he said, because there are better opportunities to control problematic insects when almonds are not in bloom.

"I was surprised—even the experts in California were surprised—that they were using insecticides during pollination," Johnson said.

While these products were considered "bee-safe," that was based on tests with adult bees that hadn't looked into the impact they had on larvae.

"I think it was a situation where it wasn't disallowed. The products were thought to be bee-safe and you've got to spray a fungicide during bloom anyway, so why not put an insecticide in the tank, too?"

Insecticides are fairly inexpensive, but the process of spraying is labor-intensive, so growers choosing to double up may have been looking to maximize their investment, he said.

"The thing is, growers were using these insecticides to control a damaging insect—the peach twig borer—during this period, but they have other opportunities to do that before the bees enter the almond orchards or after they are gone," Johnson said.

This research could open the door to more study of fungicide and pesticide use on other bee-dependent crops, including pumpkins and cucumbers, Johnson said.

Explore further: Almond-crop fungicides a threat to honey bees

More information: Andrea Wade et al, Combined Toxicity of Insecticides and Fungicides Applied to California Almond Orchards to Honey Bee Larvae and Adults, Insects (2019). DOI: 10.3390/insects10010020

Provided by: The Ohio State University

https://phys.org/news/2019-02-culprit-honeybee-deaths-california-almond.html

Bee Mite Arrival in Hawaii Causes Pathogen Changes in Honeybee Predators

UC Riverside By Iqbal Pittalwala January 8, 2019

bee mite arrival in Hawaii.jpg

UC Riverside-led research, done on the Big Island, shows effects of mite introduction have cascaded through entire pathogen communities

The reddish-brown varroa mite, a parasite of honeybees and accidentally introduced in the Big Island of Hawaii in 2007-08, is about the size of a pinhead. Yet, its effects there are concerning to entomologists because the mite is found nearly everywhere honeybees are present.

A team led by entomologists at the University of California, Riverside, performed a study on the Big Island and found viruses associated with the mite have spilled over into the western yellowjacket, a honeybee predator and honey raider. The result is a hidden, yet remarkable, change in the genetic diversity of viruses associated with the larger pathogen community of the mite and wasp, with repercussions yet to be understood.

Erin Wilson Rankin examines a western yellowjacket. (I. Pittalwala/UC Riverside)

Erin Wilson Rankin examines a western yellowjacket. (I. Pittalwala/UC Riverside)

“Already, we are seeing that the arrival of the varroa mite in honeybee populations in Hawaii has favored a few virulent strains,” said Erin E. Wilson Rankin, an assistant professor of entomologyand lead investigator of the study published Jan. 9 in the Proceedings of the Royal Society B. “We do not know what the effects of these strains will be. What we know is that the effects of the varroa mite have cascaded through entire communities in Hawaii and probably around the world.”

In particular, the researchers saw a loss in the diversity of deformed wing virus, or DWV, variants, resulting in new strains whose impact is hard to predict. DWV, widespread in honeybee populations globally and made up of several variants, is thought to be partly responsible for global die-off of honeybee colonies. DWV infects bumblebees and has been detected in other insects. The yellowjacket wasps can acquire this virus directly or indirectly from honeybees.

The western honey bee.

The western honey bee.

By a stroke of luck, the researchers had the benefit of studying the honeybee and yellowjacket populations on the Big Island both before and after the varroa mite was introduced there. They saw more association of honeybees with pathogens after the appearance of the mite. Indeed, some pathogens were detected in the honeybee and wasp populations only after the mite was introduced to the island.

“This is one of the first descriptions of pathogens in the western yellowjacket,” Wilson Rankin said. “Evidently, pathogens known to be associated with varroa have spread into non-bee species, despite the mite itself being a bee specialist. We suspect the spread in yellowjackets is partly due to the wasp’s propensity to prey upon bees, which is one way the wasps may be exposed to the pathogens.”

Wilson Rankin noted the pathogens are often incorrectly called “bee pathogens” because they were first found in bees. The pathogens, however, are found in a wide variety of insects.

“We are seeing entirely different predators being affected,” she said. “The mite is not vectoring viruses to the wasps. The viral spread is happening through predation and through flowers. Predators may be passing on pathogens to other species. The yellowjacket, for example, preys on both honeybees and native bees, and may explain why both bee populations are showing the same viruses.”

Wilson Rankin explained wasps have been overlooked by researchers because these arthropods do not have “warm, fuzzy, and furry connotations.”

The western yellowjacket is a honey bee predator and honey-raider.

The western yellowjacket is a honey bee predator and honey-raider.

“They look scary,” she added. “People also get stung by them. People are more afraid of wasps than bees. But our work shows we can examine the health of the arthropod community by using species other than bees. We show for the first time that a predator is being affected by a parasite that does not even infect it.”

The researchers sampled 25-45 bees and wasps for one part of the study, and then about 100 individuals, analyzed in groups, for each of the species during the period before and after the mite was introduced to the Big Island. The researchers did not study native bees, focusing instead on honeybees and yellowjacket wasps, neither of which is native to Hawaii. 

“Our findings suggest that pathogen transmission from domesticated bees, such as honeybees, may be important even for non-bee insects like the wasps we studied,” said Kevin J. Loope, the research paper’s first author, who worked as a postdoctoral scholar in the Wilson Rankin lab during the study. “The impacts may be more subtle than previously observed: we found changes in the genetic variation of viruses found in the wasps, but not changes in the amount of virus. These findings suggest we should look more broadly and in greater detail to figure out how moving domesticated bees for agriculture may influence wild populations of insects.

Loope, now a research assistant professor in the Department of Biology at Georgia Southern University, explained that finding overlap in the pathogens of yellowjacket wasps and domesticated bees also means that using pathogens to control undesirable wasp populations is risky.

“Any biological control efforts using pathogens should be carefully evaluated to prevent inadvertent harm to beneficial bees,” he said.

Kevin Loope excavates a yellowjacket nest in Volcano, Hawaii. (Jessica Purcell/UC Riverside)

Kevin Loope excavates a yellowjacket nest in Volcano, Hawaii. (Jessica Purcell/UC Riverside)

He added that the research team was surprised to find a dramatic difference in the viral genetic diversity between the wasp samples from the two periods — before and after the varroa mite was detected on the Big Island.

“We had predicted we would observe a decline in wasp viral diversity matching the decline described in honeybees in Hawaii, but we were still surprised to see this borne out in the data,” he said. “It’s not so often that you see what you’ve predicted in biology.”

Wilson Rankin and Loope were joined in the research by Philip J. Lester of Victoria University of Wellington, New Zealand; and James W. Baty of Malaghan Institute of Medical Research, New Zealand. Genetic analyses on the bee and wasp samples were performed at UCR and in New Zealand.

Wilson Rankin was supported by grants from the National Science Foundation and the Hellman Fellows Fund. Loope was supported by a postdoctoral fellowship from the National Institute of Food and Agriculture of the U.S. Department of Agriculture.

https://news.ucr.edu/articles/2019/01/08/bee-mite-arrival-hawaii-causes-pathogen-changes-honeybee-predators

Stronger Pesticide Regulations Likely Needed To Protect All Bee Species, Say Studies

Wild bee Credit: Nigel Raine

Wild bee Credit: Nigel Raine

December 11, 2018, University of Guelph

Pesticide regulations designed to protect honeybees fail to account for potential health threats posed by agrochemicals to the full diversity of bee species that are even more important pollinators of food crops and other plants, say three new international papers co-authored by University of Guelph biologists.

As the global human population grows, and as pollinators continue to suffer declines caused by everything from habitat loss to pathogens, regulators need to widen pesticide risk assessments to protect not just honeybees but other species from bumblebees to solitary bees, said environmental sciences professor Nigel Raine, holder of the Rebanks Family Chair in Pollinator Conservation.

"There is evidence that our dependency on insect-pollinated crops is increasing and will continue to do so as the global population rises," said Raine, co-author of all three papers recently published in the journal Environmental Entomology.

With growing demands for crop pollination outstripping increases in honeybee stocks, he said, "Protecting wild pollinators is more important now than ever before. Honeybees alone simply cannot deliver the crop pollination services we need."

Government regulators worldwide currently use honeybees as the sole model species for assessing potential risks of pesticide exposure to insect pollinators.

But Raine said wild bees are probably more important for pollination of food crops than managed honeybees. Many of those wild species live in soil, but scientists lack information about exposure of adult or larval bees to pesticides through food or soil residues.

The papers call on regulators to look for additional models among solitary bees and bumblebees to better gauge health risks and improve protection for these species.

"Everybody is focused on honeybees," said Angela Gradish, a research associate in the School of Environmental Sciences and lead author of one paper, whose co-authors include Raine and SES Prof. Cynthia Scott-Dupree. "What about these other bees? There are a lot of unknowns about how bumblebees are exposed to pesticides in agricultural environments."

She said bumblebee queens have different life cycles than honeybee counterparts that may increase their contact with pesticides or residues while collecting food and establishing colonies.

"That's a critical difference because the loss of a single bumblebee queen translates into the loss of the colony that she would have produced. It's one queen, but it's a whole colony at risk."

Like honeybees, bumblebees forage on a wide variety of flowering plants. But because bumblebees are larger, they can carry more pollen from plant to plant. They also forage under lower light conditions and in cloudier, cooler weather that deter honeybees.

Those characteristics make bumblebees especially vital for southern Ontario's greenhouse growers.

"Greenhouse tomato producers rely on commercial bumblebee colonies as the only source of pollination for their crops," said Gradish.

The new studies stem from workshops held in early 2017 involving 40 bee researchers from universities and representatives of agrochemical industries and regulatory agencies in Canada, the United States and Europe, including Canada's Pest Management Regulatory Agency.

"I hope we can address shortfalls in the pesticide regulatory process," said Raine, who attended the international meeting held in Washington, D.C.

"Given the great variability that we see in the behaviour, ecology and life history of over 20,000 species of bees in the world, there are some routes of pesticide exposure that are not adequately considered in risk assessments focusing only on honeybees."

Read at: https://phys.org/news/2018-12-stronger-pesticide-bee-species.html#jCp

Explore further: Bee flower choices altered by exposure to pesticides

More information: Environmental Entomology (2018). DOI: 10.1093/ee/nvy103 , https://academic.oup.com/ee/advance-article/doi/10.1093/ee/nvy103/5216322 

Provided by: University of Guelph

The More Pesticides Bees Eat, The More They Like Them

Science Daily / Imperial College London     August 28, 2018

Bumblebee. Credit: © Jolanta Mayerberg / FotoliaBumblebees acquire a taste for pesticide-laced food as they become more exposed to it, a behaviour showing possible symptoms of addiction.

This study of bumblebee behaviour indicates that the risk of pesticide-contaminated food entering bee colonies may be higher than previously thought, which can have impacts on colony reproductive success.

In research published today in Proceedings of the Royal Society B, a team from Imperial College London and Queen Mary University of London (QMUL) have shown that bumblebee colonies increasingly feed on pesticide-laced food (sugar solution) over time.

The researchers tested the controversial class of pesticides the 'neonicotinoids', which are currently one of the most widely used classes of pesticides worldwide, despite the near-total ban in the EU. The impact of neonicotinoids on bees is hotly debated, and the ban is a decision that has received mixed views.

Lead researcher Dr Richard Gill, from the Department of Life Sciences at Imperial, said: "Given a choice, naïve bees appear to avoid neonicotinoid-treated food. However, as individual bees increasingly experience the treated food they develop a preference for it.

"Interestingly, neonicotinoids target nerve receptors in insects that are similar to receptors targeted by nicotine in mammals. Our findings that bumblebees acquire a taste for neonicotinoids ticks certain symptoms of addictive behaviour, which is intriguing given the addictive properties of nicotine on humans, although more research is needed to determine this in bees."

The team tracked ten bumblebee colonies over ten days, giving each colony access to its own foraging arena in which bees could choose feeders that did or did not contain a neonicotinoid.

They found that while the bees preferred the pesticide-free food to begin with, over time they fed on the pesticide-laced food more and visited the pesticide-free food less. They continued to prefer the pesticide-laced food even when the positions of the feeders were changed, suggesting they can detect the pesticide inside the food.

Lead author Dr Andres Arce, from the Department of Life Sciences at Imperial, said: "Many studies on neonicotinoids feed bees exclusively with pesticide-laden food, but in reality, wild bees have a choice of where to feed. We wanted to know if the bees could detect the pesticides and eventually learn to avoid them by feeding on the uncontaminated food we were offering.

"Whilst at first it appeared that the bees did avoid the food containing the pesticide, we found that over time the bumblebees increased their visits to pesticide-laden food. We now need to conduct further studies to try and understand the mechanism behind why they acquire this preference."

Dr Gill added: "This research expands on important previous work by groups at Newcastle and Dublin Universities. Here, we added a time dimension and allowed the bees to carry out more normal foraging behaviour, to understand the dynamics of pesticide preference. Together these studies allow us to properly assess the risks of exposure and not just the hazard posed.

"Whilst neonicotinoids are controversial, if the effects of replacements on non-target insects are not understood, then I believe it is sensible that we take advantage of current knowledge and further studies to provide guidance for using neonicotinoids more responsibly, rather than necessarily an outright ban."


Story Source:

Materials provided by Imperial College London. Original written by Hayley Dunning. Note: Content may be edited for style and length.


Journal Reference:

Andres N. Arce, Ana Ramos Rodrigues, Jiajun Yu, Thomas J. Colgan, Yannick Wurm, Richard J. Gill. Foraging bumblebees acquire a preference for neonicotinoid-treated food with prolonged exposure. Proceedings of the Royal Society B: Biological Sciences, 2018; 285 (1885): 20180655 DOI: 10.1098/rspb.2018.0655

https://www.sciencedaily.com/releases/2018/08/180828204911.htm?utm_source=dlvr.it&utm_medium=facebook

National Honey Bee Day 2018: Brush Up On Your Knowledge of Bee Protection

University of California - Kearney News Updates    By Stephanie Parreira    August 15, 2018

Honey bee on almond blossom. Photo by Jack Kelly Clark.Celebrate National Honey Bee Day by brushing up on your knowledge of bee protection—check out the newly revised Best Management Practices to Protect Bees from Pesticides and Bee Precaution Pesticide Ratings from UC IPM. These resources will help you strike the right balance between applying pesticides to protect crops and reducing the risk of harming our most important pollinators.

The best management practices now contain important information regarding the use of adjuvants and tank mixes, preventing the movement of pesticide-contaminated dust, and adjusting chemigation practices to reduce bee exposure to pesticide-contaminated water. The Bee Precaution Pesticide Ratings have also been updated to include ratings for 38 new pesticides, including insecticides (baits, mixtures, and biological active ingredients), molluscicides (for snail and slug control), and fungicides.

Most tree and row crops are finished blooming by now, but it is a good idea to learn about bee protection year-round. Visit these resources today to choose pesticides that are least toxic to bees and learn how you can help prevent bees from being harmed by pesticide applications.

http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=27973

Protecting Honey Bees and Wild Pollinators From Pesticides

Beyond Pesticides

Beyond Pesticides advocates for widespread adoption of organic management practices as key to protecting pollinators and the environment, and has long sought a broad-scale marketplace transition to organic practices that legally prohibits the use of toxic synthetic pesticides, and encourages a systems-based approach that is protective of health and the environment. Learn more (below) on the role that pesticides play in pollinator decline, and actions you can take to BEE Protective. For information on growing plants to protect pollinators, see our Pollinator-Friendly Seeds and Nursery Directory. Use the Bee Protective Habitat Guide to plant a pollinator garden suited for your region, and consider seeding white clover into your lawn; learn more from Taking a Stand on Clover.

Read more: https://www.beyondpesticides.org/programs/bee-protective-pollinators-and-pesticides/bee-protective

Breakthrough Could Aid Development of Bee-Friendly Pesticides

Science Daily    University of Exeter     March 22, 2018

A new discovery opens up the door to designing bee-friendly insecticides. Credit: © Igor / Fotolia

Efforts to create pesticides that are not toxic to bees have been boosted by a scientific breakthrough.

A joint study by the University of Exeter, Rothamsted Research and Bayer AG has discovered the enzymes in honeybees and bumblebees that determine how sensitive they are to different neonicotinoid pesticides.

The potential impact of neonicotinoids on bee health is a subject of intensive research and considerable controversy, with the European Union having restricted three compounds on crops that are attractive to bees in 2013.

However, both honeybees and bumblebees exhibit profound differences in their sensitivity to different members of this insecticide class. The researchers aimed to understand why this is, in order to aid the development of pesticides that are non-toxic to them.

Just as in other organisms, toxins in bees can be broken down by enzymes called cytochrome P450s. The study identified one subfamily of these enzymes in bees -- CYP9Q -- and found it was responsible for the rapid breakdown of certain neonicotinoids.

"Identifying these key enzymes provides valuable tools to screen new pesticides early in their development to see if bees can break them down," said Professor Chris Bass, who led the team at the University of Exeter.

"It can take a decade and $260 million to develop a single pesticide, so this knowledge can help us avoid wasting time and money on pesticides that will end up with substantial use restrictions due to intrinsic bee toxicity."

Dr Ralf Nauen, insect toxicologist and lead investigator of the study at Bayer added: "Knowing the mechanisms contributing to inherent tolerance helps us and regulators to better understand why certain insecticides have a high margin of safety to bees."

"The knowledge from our study can also be used to predict and prevent potential harmful effects that result from inadvertently blocking these key defence systems, for instance by different pesticides (such as certain fungicides) that may be applied in combination with insecticides."

Professor Lin Field, Head of the Department of Biointeractions and Crop Protection at Rothamsted Research added: "Some neonicotinoids are intrinsically highly toxic to bees but others have very low acute toxicity, but in public debate they tend to get tarred with the same brush.

"Each insecticide needs to be considered on its own risks and merits, not just its name."

The researchers carried out the most comprehensive analysis of bee P450 detoxification enzymes ever attempted.

Comparing the effects of two neonicotinoids, they found bees metabolise thiacloprid very efficiently, while they metabolise imidacloprid much less efficiently.

Although previous work had suggested rate of metabolism might explain why bees react differently to different neonicotinoids, the specific genes or enzymes were unknown until now.

The research was part funded by Bayer, which is a manufacturer of neonicotinoid insecticides.


Story Source:

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


Journal Reference:

Cristina Manjon, Bartlomiej J. Troczka, Marion Zaworra, Katherine Beadle, Emma Randall, Gillian Hertlein, Kumar Saurabh Singh, Christoph T. Zimmer, Rafael A. Homem, Bettina Lueke, Rebecca Reid, Laura Kor, Maxie Kohler, Jürgen Benting, Martin S. Williamson, T.G. Emyr Davies, Linda M. Field, Chris Bass, Ralf Nauen. Unravelling the Molecular Determinants of Bee Sensitivity to Neonicotinoid Insecticides. Current Biology, 2018; DOI: 10.1016/j.cub.2018.02.045

https://www.sciencedaily.com/releases/2018/03/180322125021.htm

How Bees Defend Against Some Controversial Insecticides

ScienceNews.org     By Dan Garisto    March 22, 2018

Researchers have discovered enzymes that can help resist some neonicotinoids

WHAT’S THE BUZZ Honeybees (shown) and bumblebees can resist a type of neonicotinoid insecticide thanks to a family of enzymes that metabolize toxic compounds.

Honeybees and bumblebees have a way to resist toxic compounds in some widely used insecticides.

These bees make enzymes that help the insects break down a type of neonicotinoid called thiacloprid, scientists report March 22 in Current Biology. Neonicotinoids have been linked to negative effects on bee health, such as difficulty reproducing in honeybees (SN: 7/26/16, p 16). But bees respond to different types of the insecticides in various ways. This finding could help scientists design versions of neonicotinoids that are less harmful to bees, the researchers say.

Such work could have broad ramifications, says study coauthor Chris Bass, an applied entomologist at the University of Exeter in England. “Bees are hugely important to the pollination of crops and wild flowers and biodiversity in general.”

Neonicotinoids are typically coated on seeds such as corn and sometimes sprayed on crops to protect the plants from insect pests. The chemicals are effective, but their use has been suspected to be involved in worrisome declines in numbers of wild pollinators (SN Online: 4/5/12).  

Maj Rundlöf, of Lund University in Sweden, helped raise the alarm about the insecticides. In 2015, she reported that neonicotinoid-treated crops reduced the populations of bees that fed from the plants. Rundlöf, who was not involved with the new study, says the new research is important because it clarifies differences between the insecticides. “All neonicotinoids are not the same,” she says. “It’s a bit unrealistic to damn a whole group of pesticides.”

Bass and his colleagues, which include scientists from Bayer, one of the main producers of neonicotinoids, investigated resistance to thiacloprid by looking at bees’ defense systems. The team focused on enzymes known as P450s, which can metabolize toxic chemicals, breaking them down before they affect the bee nervous system. The researchers used drugs to inhibit groups of P450 enzymes. When the family enzymes called CYP9Q was inhibited, bees became 170 times as sensitive to thiacloprid, dying from a much smaller dose, the researchers found. Discovering the enzymes’ protective power could lead to more effective ways to simultaneously avoid harming bees and help crops.

“We live in an era that uses pesticides,” Rundlöf says. “We need to figure out the ones that are safest.”

Citations:
C. Manjon et al. Unravelling the molecular determinants of bee sensitivity to neonicotinoid insecticides. Current Biology. Published online March 22, 2018. doi:10.1016/j.cub.2018.02.045.

Further Reading:
L. Hamers. Much of the world’s honey now contains bee-harming pesticides. Science News. Vol. 192, October 28, 2017, p. 16.

S. Milius. Neonicotinoids are partial contraceptives for male honeybees. Science News. Vol. 190, August 20, 2016, p. 16.

S. Milius. Bees may like neonicotinoids, but some may be harmed. Science News. Vol. 187, May 16, 2015, p. 13.

J. Raloff. Yet another study links insecticide to bee losses. Science News Online, April 5, 2012.

https://www.sciencenews.org/article/how-bees-defend-against-some-controversial-insecticides

NC State Researcher Awarded Grant to Improve Honeybee Health

NC State University     By Dee Shore     March 14, 2018

David Tarpy, of the Department of Entomology and Plant Pathology, leads new CALS research related to honeybee health.With a grant from the Foundation for Food and Agriculture Research’s Pollinator Health Fund, NC State University scientist David Tarpy is researching the impact of pesticide exposure on honeybee colony disease prevalence and reproductive potential.

Tarpy, a professor of entomology and plant pathology and the NC State Extension apiculturist, recently received a $217,000 grant from FFAR, a nonprofit established through bipartisan congressional support in the 2014 Farm Bill. The FFAR grant is being matched by a graduate fellowship from the North Carolina Agricultural Foundation Inc., supporting a Ph.D. student in the NC State Apiculture Program, Joe Milone.

Milone and Tarpy’s research will generate new knowledge about the multiple interacting stressors that lead to declines in pollinator populations. “By studying the interactions among queens, pesticides and disease, we are determining how the entire exposome – or all of the things that the queen and colony are exposed to – affects overall bee health,” Tarpy said.

Noting that managed and native pollinators are vital to many crop production systems and the ecological resources that support them, FFAR Executive Director Sally Rockey congratulated Tarpy and NC State for undertaking research that will inform science-based approaches to improving pollinator health.

FFAR established its Pollinator Health Fund in response to the agricultural threat posed by declining pollinator health. Insect pollinators contribute an estimated $24 billion to the United States economy annually.

NC State is one of 16 organizations that received a total of $7 million in FFAR funding toward research and technology development designed to contribute to healthy pollinator populations that support crop yields and agricultural ecosystems.

To learn more about the FFAR Pollinator Health Fund, please visit foundationfar.org/pollinator-health-fund/.

https://cals.ncsu.edu/news/nc-state-researcher-awarded-grant-to-improve-honeybee-health/

Weed-Killer Prompts Angry Divide Among US Farmers

MSN News    By Juliette Michael     November 12, 2017

© Getty Brian Smith and his cousin Hughes, both fifth generation soybean farmers, stand in soybean fields their family tend to that show signs of having been affected by Dicamba use.Little Rock (United States) (AFP) - When it comes to the herbicide dicamba, farmers in the southern state of Arkansas are not lacking for strong opinions.

"Farmers need it desperately," said Perry Galloway.

"If I get dicamba on (my products), I can't sell anything," responded Shawn Peebles.

The two men know each other well, living just miles apart in the towns of Gregory and Augusta, in a corner of the state where cotton and soybean fields reach to the horizon and homes are often miles from the nearest neighbor.

But they disagree profoundly on the use of dicamba.

Last year the agro-chemical giant Monsanto began selling soy and cotton seeds genetically modified to tolerate the herbicide.

The chemical product has been used to great effect against a weed that plagues the region, Palmer amaranth, or pigweed -- especially since it became resistant to another herbicide, glyphosate, which has become highly controversial in Europe over its effects on human health.

The problem with dicamba is that it vaporizes easily and is carried by the wind, often spreading to nearby farm fields -- with varying effects.

Facing a surge in complaints, authorities in Arkansas early this summer imposed an urgent ban on the product's sale. The state is now poised to ban its use between April 16 and October 31, covering the period after plants have emerged from the soil and when climatic conditions favor dicamba's dispersal.

- A bitter dispute -

"Dicamba has affected my whole family," said Kerin Hawkins, her voice trembling. Her brother, Mike Wallace, died last year during an altercation with a worker from a neighboring farm whom he had met to discuss his concerns over the herbicide.

A jury is set to rule on whether Wallace's fatal shooting constituted homicide or self-defense.

This year, the family says, drifting dicamba has affected some 75 acres (30 hectares) of peanuts and 10 acres of new varieties of vegetables planted on their farm, sharply reducing profits.

To protect themselves against the product's impact, the family has decided to plant cotton seeds genetically modified to resist dicamba.

"This is not just a dicamba issue, this is not just a Monsanto issue, this is about how we as human beings treat other people," Kerin Hawkins said.

She was testifying Wednesday at a public hearing in Little Rock, the state capitol, organized by the agency that regulates pesticide and herbicide use in Arkansas.

Immediately afterward the agency called for curbs on the use of dicamba, a decision subject to legislative approval.

So large was the turnout for the hearing that the agency had to move it from its own offices to a meeting room in a hotel. In all, 37 people stepped up to the microphone to explain -- often in voices shaking with emotion -- why they favored or strongly opposed the product.

- Dealing with diversity -

"I'm here to tell you we used dicamba and we had a wonderful year," said Harry Stephens, who with his son grows soybeans in Phillips County.

At a time when some younger farmers are struggling to make ends meet, he said, banning dicamba could "put them out of business."

Richard Coy, who raises bees, said dicamba has had a devastating impact on hives located near farm fields where dicamba is in use.

"I lost $500,000 in honey production and $200,000 worth of pollination contracts to California farms due to the poor health of my beehives," he said.

On the edge of his farm field, Perry Galloway points out some of the weeds -- dead but still standing, many of them head-high -- that ruined several of his past crops.

He has since sprayed dicamba twice over an area of 4,000 acres, and says that "we had the cleanest fields we had in a long time."

He favors a compromise, allowing the herbicide to be applied only once, after plants have sprouted.

But Shawn Peebles, who grows organic vegetables, was able to deal with pigweed by hiring workers to pull them up by hand.

"It is known for a fact dicamba will move," he said. If he gets any in his fields -- which has not happened this year -- "I have to destroy the crop."

"Diversity is what made agriculture what it is today," he said.

"It is not just dicamba (and) soybeans; there is organic farms such as myself, there is vineyards in Arkansas, and we all need to work together."

https://www.msn.com/en-us/news/us/weed-killer-prompts-angry-divide-among-us-farmers/ar-BBET8RH?li=BBnb7Kz

Bee-Harming Pesticides In 75 Percent Of Honey Worldwide: Study

 PHYS.ORG    By Kerry Sheridan     October 5, 2017

Bees help pollinate 90 percent of the world's major crops, but in recent years have been dying off from "colony collapse disorder" Read more at: https://phys.org/news/2017-10-bee-harming-pesticides-percent-honey-worldwide.

Traces of pesticides that act as nerve agents on bees have been found in 75 percent of honey worldwide, raising concern about the survival of these crucial crop pollinators, researchers said Thursday.

Human health is not likely at risk from the concentrations detected in a global sampling of 198 types of honey, which were below what the European Union authorizes for human consumption, said the report in the journal Science.

However, the study found that 34 percent of honey samples were contaminated with "concentrations of neonicotinoids that are known to be detrimental" to bees, and warned that chronic exposure is a threat to bee survival.

Bees help pollinate 90 percent of the world's major crops, but in recent years have been dying off from "colony collapse disorder," a mysterious scourge blamed on mites, pesticides, virus, fungus, or some combination of these factors.

"The findings are alarming," said Chris Connolly, a neurobiology expert at the University of Dundee, who also wrote a Perspective article alongside the research in Science.

"The levels detected are sufficient to affect bee brain function and may hinder their ability to forage on, and pollinate, our crops and our native plants."

Neonicotinoids have been declared a key factor in bee decline worldwide, and the European Union issued a partial ban on their use in 2013.

For the Science study, the European samples were collected largely before this ban took effect, Connolly said. Further research is needed to gauge the effectiveness of the EU steps.

Five common pesticides

Bees collect nectar as they pollinate plants, and over time this sugary liquid accumulates into the thick syrup of honey.

To test contamination levels, samples of honey were taken from local producers worldwide, and researchers tested for five commonly used neonicotinoids: acetamiprid, clothianidin, imidacloprid, thiacloprid, and thiamethoxam.

These pesticides, introduced in the mid 1990s, are based on the chemical structure of nicotine and attack the nervous systems of insect pests.

"Overall, 75 percent of all honey samples contained at least one neonicotinoid," said the study, led by Edward Mitchell of the University of Neuchatel in Switzerland.

"Of these contaminated samples, 30 percent contained a single neonicotinoid, 45 percent contained two or more, and 10 percent contained four or five."

The frequency of contamination was highest in the North American samples (86 percent), followed by Asia (80 percent) and Europe (79 percent).

The lowest concentrations were seen in South American samples (57 percent).

"These results suggest that a substantial proportion of world pollinators are probably affected by neonicotinoids," said the study.

'Serious concern'

Our planet is home to some 20,000 species of bees, which fertilize more than 90 percent of the world's 107 major crops.

The United Nations warned in 2016 that 40 percent of invertebrate pollinators—particularly bees and butterflies—risk global extinction.

Experts said that while the findings are not exactly a surprise, the threat posed by neonicotinoids should be taken seriously.

"The levels recorded (up to 56 nanogram per gram) lie within the bioactive range that has been shown to affect bee behavior and colony health," said plant ecologist Jonathan Storkey, who was not involved in the study.

"Scientists showed earlier this year that levels of less than 9 ng/g reduced wild bee reproductive success," he added.

"I therefore agree with the authors that the accumulation of pesticides in the environment and the concentrations found in hives is a serious environmental concern and is likely contributing to pollinator declines."

According to Lynn Dicks, natural environment research council fellow at the University of East Anglia, the findings are "sobering" but don't offer a precise picture of the threat to bees.

"The severity of the global threat to all wild pollinators from neonicotinoids is not completely clear from this study, because we don't know how the levels measured in honey relate to actual levels in nectar and pollen that wild pollinators are exposed to," she said.

The levels of exposure to harmful pesticides may be far higher than what can be measured in honey, said Felix Wackers, a professor at Lancaster University who was not involved in the research.

"This shows that honeybees are commonly exposed to this group of pesticides while collecting neonicotinoid-contaminated nectar from treated crops or from flowers that have come into contact with spray drift or soil residues," he said.

"The actual level of exposure can be substantially higher, as the honey samples analyzed in this study represents an average of nectar collection over time and space."

Read more at: https://phys.org/news/2017-10-bee-harming-pesticides-percent-honey-worldwide.html#jCp

Field Tests Show How Pesticides Can Wreak Havoc on Honeybees

Los Angeles Times/Science Now   By Mira Abed     June 29, 2017

CLICK IMAGE TO VIEW VIDEO AT LA TIMES: York University Professor Amro Zayed explains how a class of pesticides known as neonicotinoids can leach into the environment, harming honeybee workers and queens. (Credit: York University)

Humans are big fans of bees. We rely on them to pollinate crops like almonds, watermelons and apples.

But bees probably aren’t big fans of humans — at least, not of our agricultural practices.

In particular, they ought to be offended by our fondness for a widely used class of pesticides called neonicotinoids (neonics, for short).

Studies in the lab have shown that some doses of neonics are outright lethal to many bees and that even sub-lethal doses can shorten a colony’s lifespan and harm its overall health. Results have been similar in small-scale field studies.

A red-belted bumblebee covered in pollen visits a chive flower in Canada. (Jeremy T. Kerr)

Still, exactly how these pesticides, which are applied to seeds before planting, would affect bees in the real world remains something of a mystery. Scientists have been locked in a fierce debate over how much — and for how long — bees encounter these pesticides in their daily lives. After all, the conditions in a field are far more complex than those in a lab.

Now, two studies published side by side in the journal Science attempt to answer this contentious question.

One of the studies was conducted in Canada. It combined large-scale field work and laboratory experiments to better understand real-world neonic exposure levels and their effects on honeybees.

The other was conducted in large fields in Hungary, Germany and the U.K. Its goal was to understand how the effects of neonics vary between countries and how exposure during the flowering season affects the long-term health of a bee colony.

The research, published Thursday, provides a lot of new information and poses still more questions. Here are some of the key takeaways:

Bees are exposed to neonicotinoids for longer than we thought

In the Canadian study, biologist Amro Zayed and his team at York University in Toronto monitored 55 honeybee colonies in 11 locations from May through September 2014, a longer time than previously measured. They found that honeybees placed near cornfields planted with neonic-coated seeds were exposed to detectable levels of neonicotinoids for three to four months.

Even some of the bees placed far away from agricultural crops were exposed for around one month as the pesticide moved through the ecosystem. (More on that in a bit).

Ecologists from the Centre for Ecology and Hydrology assess rapeseed crops planted with neonicotinoids (Centre for Ecology & Hydrology)

In the European study, a team led by Ben Woodcock and Richard Pywell from the Centre for Ecology and Hydrology in England studied bees in 33 sites, each split into areas that were treated with pesticides and areas that weren’t. They found that bees were exposed to neonics even in the untreated fields. This was particularly surprising considering that the chemicals have been restricted in Europe since 2014.

The researchers said this indicates that the pesticides remain in the environment long after a treated crop has been harvested.

Real-world doses of neonicotinoids are bad for bees

In general, both studies showed that the concentrations of neonicotinoids that bees actually encounter in fields are indeed dangerous for bees.

Woodcock’s team found that, in Hungary and the U.K., the more neonicotinoids there were in the ecosystem, the smaller the size of the honeybee colonies and the lower the fertility rate of wild bees.

Zayed and his team showed that worker honeybees died around five days sooner when exposed to neonics. That amounted to a 23% decrease in lifespan.

Exposed worker bees also displayed different behavior than unexposed bees. They tended to fly farther from the hive, as if they were lost. That symptom has been seen in previous studies.

A honeybee worker has an RFID attached to its back that allows York University researchers to monitor when it leaves and returns to the colony, as well as when it no longer is active and presumed dead. (Amro Zayed, York University)

A honeybee worker has an RFID attached to its back that allows York University researchers to monitor when it leaves and returns to the colony, as well as when it no longer is active and presumed dead. (Amro Zayed, York University)

The worker bees also were slower to recognize and remove dead or dying bees from the hive. This is important because removal keeps colonies healthy by eliminating potential sources of disease, Zayed said.

Perhaps most devastating, exposed honeybee colonies had difficulty keeping a laying queen. This can be catastrophic because if a replacement queen is not raised within three days of the previous queen’s death, no new eggs can be produced, and the colony will quickly die.

Between 70% and 80% of Zayed’s exposed colonies would have died without outside help, he said.

Neonic exposure can come from untreated plants

In both studies, neonicotinoids were found in untreated areas and plants.

Zayed’s group found that most of the contaminated pollen collected by Canadian honeybees actually was from untreated wildflowers, not from treated corn or soy.

While scientists don’t know how neonicotinoids spread in the environment, there are several plausible explanations.

Since these pesticides can dissolve in water, it is likely that dispersal occurs when neonic-contaminated water is sucked up by other plants, Zayed said.

Richard Shore and Pywell, both researchers from the Centre for Ecology and Hydrology, said that water, soil and dust are all possible ways that neonics might spread.

Environment matters — and it’s really, really complicated

One of the biggest messages from the European study is that the real world is incredibly complex, said Maj Rundlöf, who studies bees at UC Davis and Lund University and was not involved in either of the new studies. The variation is so great, both within and between countries, she said, that there must be a wide variety of factors at play.

One is the particular combination of agrochemicals to which bees are exposed. Farmland may be treated with pesticides, herbicides, fungicides and more. Just as some medications can interact with others, Zayed said, agrochemicals can join forces to intensify harm to bees.

Zayed’s team analyzed the toxicity effects of the two most common combinations found in their field tests. In one case, the results were startling: When the neonicotinoid thiamethoxam was combined with the fungicide boscalid, the neonic became twice as toxic to honeybees.

An eastern bumblebee pollinates lupine flowers in Canada. (Jeremy T. Kerr)

Additionally, the Woodcock team found that neonics had different effects in different countries. The pesticides did the least damage in Germany, and the team has a number of ideas as to why.

The German bee colonies were much healthier overall, with fewer instances of disease and parasites. They also had different diets, consisting of only about 15% neonic-treated rapeseed; in Hungary and the U.K., by contrast, rapeseed accounts for 40% to 50% of the diet.

This doesn’t necessarily mean we should ban neonicotinoids

The study authors and multiple other experts said it would be premature to ban neonicotinoids.

Norman Carreck, who researches bees at the University of Sussex and did not work on the new studies, said the EU’s 2014 moratorium on neonics has led to pest problems in England. The moratorium forced farmers to use alternative pesticides, and their effects on bees are mostly unknown.

“Farmers do an important job,” Zayed said. In making a decision about neonicotinoid use, we need to find a solution that “would reduce the cost to pollinators but at the same time still allow farmers to produce an economically viable crop.”

http://www.latimes.com/science/sciencenow/la-sci-sn-bees-pesticides-neonicotinoids-20170629-htmlstory.html

Probiotics Could Improve Survival Rates in Honey Bees Exposed to Pesticides, Study Finds

Science Daily     Source: Lawson Health Research Institute    June 19, 2017

In a new study from Lawson Health Research Institute (Lawson) and Western University, researchers have shown that probiotics can potentially protect honey bees from the toxic effects of pesticides.

Honey bees are critical to agriculture as they pollinate approximately 35 per cent of the global food crop, contributing an estimated $4.39 billion per year to the Canadian economy. Pesticides are currently used to maximize crop yields, but the most common pesticides, neonicotinoid insecticides, are a major factor in colony collapse disorder which is killing honey bee populations.

"The demise of honey bees would be disastrous for humankind. A current dilemma in agriculture is how to prevent bee decline while mitigating crop losses," says Dr. Gregor Reid, Director for the Canadian Centre for Human Microbiome and Probiotic Research at Lawson, and Professor at Western's Schulich School of Medicine & Dentistry. "We wanted to see whether probiotics could counter the toxic effects of pesticides and improve honey bee survival."

The study was performed by trainees Brendan Daisley and Mark Trinder in Dr. Reid's lab at St. Joseph's Hospital in London, Ontario. The researchers utilized fruit flies as a well-known model for studying pesticide toxicity in honey bees. Both insects are affected similarly by neonicotinoids, have very similar immune systems, and share many common microbes present in their microbiota -- the collection of microorganisms found in each insect.

The researchers found that fruit flies exposed to one of the world's most commonly used pesticides, imidacloprid (IMI), experienced changes to their microbiota and were more susceptible to infections. The flies were exposed to a comparable amount of pesticide as honey bees in the field.

By administering a specific strain of probiotic lactobacilli, survival among fruit flies exposed to the pesticide improved significantly. The mechanism involved stimulating the immune system through a pathway that insects use to adapt to infection, heat and other stresses.

"Our study showed that probiotic lactobacilli can improve immunity and potentially help honey bees to live longer after exposure to pesticides," says Daisley, an MSc candidate. He notes that probiotic lactobacilli could be easily administered through pollen patties, which are used by beekeepers to provide nutritional support and anti-pesticide effects to honey bees.

Over the winter months, honey bee mortality has been steadily increasing with ranges of 38 to 58 per cent in recent years, two to three times higher than the sustainable level. In Ontario alone, 340 bee keepers reported an abnormally high number of bee deaths, with over 70 per cent of dead bees testing positive for neonicotinoid residues (Government of Ontario).

"While cessation of pesticide use would be ideal, farmers currently have little alternative to obtain the yields that keep their businesses viable," says Dr. Reid. "Until we can cease using pesticides, we need to find ways to protect humans and wildlife against their side effects. Probiotics may prove as an effective protective intervention against colony collapse disorder."

The researchers hope to further study the mechanisms involved in this process and perform field tests on honey bee populations in Ontario.

Story Source: Materials provided by Lawson Health Research Institute. Note: Content may be edited for style and length.

Journal Reference: Brendan A. Daisley, Mark Trinder, Tim W. McDowell, Hylke Welle, Josh S. Dube, Sohrab N. Ali, Hon S. Leong, Mark W. Sumarah, Gregor Reid. Neonicotinoid-induced pathogen susceptibility is mitigated by Lactobacillus plantarum immune stimulation in a Drosophila melanogaster model. Scientific Reports, 2017; 7 (1) DOI: 10.1038/s41598-017-02806-w

https://www.sciencedaily.com/releases/2017/06/170619101827.htm

After Massive Bee Kill, Beekeepers Want Answers From Fresno County

Capital Public Radio / News     By Julia Metric    May 16, 2017

Dead bees in Reedley, CA from colonies belonging to Rafael Reynaga. (Photo courtesy of Rafael Reynaga.) 

The Beekeeper

When Rafael Reynaga came to check on his bee colonies in a Fresno almond orchard, he found a carpet full of dead bees on the ground.

Reynaga picked up a hive and found two inches of bees at the bottom. He says most were dead, but a few were still moving.

Dead bees reek, Reynaga says, like a dead rat.

He's been working with bees since the 1980s but he says he'd never experienced a bee kill firsthand until this February.

He'd lent two hundred hives to his brother, fellow beekeeper Raul Reynaga. The latter had a pollination contract with an almond grower in Reedley on the east side of Fresno. 

He suspects his honeybees died from pesticide exposure.

“The bees act in a specific way when they are poisoned,” adds Reynaga. “They fly in circles close to the ground.”

Apiarist Rafael Reynaga checks bee colonies in Tulare County

To Reynaga these bee deaths point to a pesticide spray to blooming crops. But he says his hives went in before the almond bloom. The closest blooming crop were nectarines.

Reynaga filed a "Report of Loss” with the Fresno County Agricultural Commissioner’s office. He says it’s a big hit to his business - a $100,000 loss.

Protecting The Bees

Almond pollination is the busiest time of year for California’s commercial beekeepers. They scramble around the state as they move their colonies into orchards just ahead of the bloom.

Gene Brandi is president of the American Beekeeping Federation and a longtime beekeeper from Madera.

Brandi says he works with fifteen different growers across the state during pollination. It’s a logistical feat to move thousands of hives into place just before almond bloom while weather changes hour by hour. Keeping the bees healthy and safe is a huge priority.

During pollination, some beekeepers rely on a notification system to find out about pesticide applications close to their hives.

Here’s how the notification system works in Fresno County. Beekeepers can register the location of hives as they place them for pollination. It’s voluntary. The county pins those locations to a digital bee map.

This interactive map shows approximate bee locations in Fresno County. (Credit: County of Fresno)

Growers, or the pesticide applicators they work with, must file a "Notice of Intent" with the Fresno County Agricultural Commissioner if they plan to apply anything toxic to bees according to the label. 

The county has 16 hours to check the spray location against the bee map and reply to the grower (or pesticide applicator) with contact details for anyone with registered hives within a one mile radius.

The last step: the grower (or pesticide applicator) is required to message registered beekeepers with a heads-up 48 hours ahead of the spray application.

Some beekeepers choose to register their hives and receive notification, but many do not, according to the Fresno County Agricultural Commissioner's office. They say several beekeepers in the bee kill areas were not registered for February pollination.

Gene Brandi says he registers his hives with the county. It’s a valuable source of information.

But here’s the catch. Brandi says the notification system is not the main safeguard in protecting honeybees from pesticide exposure.

It’s the label.

The Label Is The Law

Just because a beekeeper gets a phone or email notification about a pesticide application does not mean they’ll move their bees out, explains Gene Brandi.

The bees are in the almond orchards to do a job - pollination. “We can’t move them out until it’s done,” says Brandi.

In California, protection for honey bees comes in the form of bee warnings on specific pesticide labels.  Carzol SP insecticide bee warning label

The label is the law. That means regardless of where hives are registered, growers (and pesticide applicators on staff) are required to follow the label’s language.

Brandi is confident growers, pesticide applicators, beekeepers and county ag officials all understand following the label to mean: only apply these pesticides at night, when honey bees are not working.

Brandi is counting on the Fresno County Agricultural Commissioner to get to the bottom of what caused the bee kills in February. Regardless of the cause, he says, “This shouldn’t have happened.”

For Brandi, seeing pictures of Reynaga’s dead bees from Reedley brought back unwelcome memories of a bee kill his brother experienced decades ago.

“You can see it’s more than a claim,” says Brandi.

“It’s losses they have experienced. It’s real. And it’s a major negative economic impact on their businesses and on the growers, too. The growers are paying for good bees and they got these dead ones that aren’t going to pollinate one nut.”

Brandi says it’s key for the entire agriculture community to follow best practices so bees are protected while crops get treated.

The Almond Board of California adopted best management practices in 2014. Those include not applying insecticides during bloom and ensuring fungicides are applied late in the day and into the evening when bees are not out collecting pollen.

“Many growers have adopted these practices, but there are still quite a few that have not. They don’t have to. It’s strictly advisory,” explains Brandi.

Earlier this spring Brandi had a meeting at the Environmental Protection Agency in Washington, DC. Brandi urged them to take a closer look at the impact of popular tank mixes on the health of honey bee colonies and consider bee warning labels for them.

(A tank mix is a cocktail of pesticides in single tank.) 

"After all, tank mixes are what our bees 'see' in the field, not just individual pesticides," says Brandi. 

Brandi argues that even if a tank mix doesn't kill adult bees outright, it may impact the brood and hurt the bee colony longterm. 

According to Brandi, the acting head of the EPA's Office of Pesticide Programs said the agency would look into tank mixes later this year.

The Investigation

There were several clusters of bee kills in Fresno this winter. They happened on the east side of Fresno County in Sanger and Reedley, where Rafael Reynaga’s colonies were.

The other area is Kerman, on the west side of the county, where loss reports from several beekeepers total in the ballpark of $2 million.

Tom Ullmann works for the Fresno County Agricultural Commissioner’s office and he’s investigating the Kerman incident. On a tour of the Kerman area, he points out one spot where honeybee colonies got hit, between two vast almond orchards.

Tom Ullmann works for the Fresno County Department of Agriculture

The county collected bee bodies and swabs from outside the hives at this site and sent them to a lab at the California Department of Pesticide Regulation

As part of the investigation, Ullmann’s examined pesticide use reports in Kerman for the days leading up to the bee kill.

“So far, there’s nothing we’ve found that has been done that is in violation of any regulatory requirements according to the label,” says Ullmann.

In other words, pesticide applications were reportedly completed by midnight.

But the preliminary finding leaves bee broker Joe Traynor doubtful.

“I can’t totally blame the county,” Traynor says, “but they depend on use reports and those are only as good as the honesty of the guy that signs them, saying what he put on and what time of day he put it on. Anybody can fudge a use report.”

Traynor’s been wrangling bees for 50 years.

Think of the bee broker as the middleman for pollination. They gather bee hives from various beekeepers to fill contracts with growers. The bee broker gets a cut from both parties.

Traynor was the one who brought Rafael Reynaga’s hives to Reedley. Bee colonies Traynor put in Kerman also got hit. And, he says, bees he placed for pollination in Sanger orchards were hit even worse.

 Bee broker Joe Traynor, left, and beekeeper Rafael Reynaga in Tulare County.

To Traynor, the volume of dead bees and their location suggest exposure to a pesticide – the kind with a bee warning on the label. He suspects a spray was applied into the early morning hours.

Stace Leoni is Fresno County Deputy Agricultural Commissioner and she’s leading the bee kill investigation.

Leoni concedes that pesticide use reports, filed after the application occurs, rely on an honor system. But she doesn’t find it credible that pesticide applicators would intentionally break the rules.

“Why would you want to spend money on a product and apply it if it wasn’t going to work? Or do it at the wrong time or use too much?” asks Leoni.

In his search for answers, Traynor’s focused on the timing of the bee kill and what was going on nearby. He placed the hives in almond orchards before bloom, so there was no forage.

“But bees will visit nearby orchards up to two or three miles away to find bloom,” Traynor explains. He points to nearby blooming nectarines.

The county’s bee lab results are not yet available. But USDA lab reports show several insecticides in bee bodies and bee pollen from Kerman. One of them is Carzol. It’s commonly used by nectarine growers to control an insect called thrips. 

In both bee kill areas there are nectarines within three miles of almonds.

Leoni says the county’s preliminary finding is that a Carzol application to nearby nectarines was completed by midnight.

The county has come under vocal criticism from bee brokers, including Traynor, who say the county must do more to enforce night-time sprays for pesticides with bee warning labels.

“A lot of statements are being made that we don't care or that we're not turning over every stone to figure this out. That’s just not true,” Leoni says.

Leoni insists the county is looking into every possible cause of the February bee deaths. And she says the investigation takes time.

“We're doing the very best we can do because we don't want it to happen again,” explains Leoni.

“But we don't go out in the beginning with accusations. We ask questions. The whole point is to stay objective and try to figure out what happened.”

Leoni says it’s too early to say what lessons could come out of the bee kill. But she concedes that “some materials that are registered may need to be looked at again as far as their toxicity to bees.”

“It could be that the window (for spraying) has to be even shorter in the evening, that you have to finish six hours before the next time bees actively visit. Or maybe a lower dosage. I don’t know,” Leoni says.

Regenerating The Bee Colonies

Rafael Reynaga stands on a grassy mound nestled along the Fresno foothills. The fragrance of citrus blossom filters through the air. 

Citrus trees in Fresno County

This idyllic bee yard is where he brought his hives after the bee kill in Reedley. 

Reynaga cleaned out the stricken hives with bleach to remove possible contamination from dead bee bodies. Then he added brood from healthy colonies and a queen cell for each colony.

He put the bee boxes in their own spot where there’s plenty of forage from citrus bloom. It's like a bee sanctuary.

“I put them where they can thrive. Now, only time will tell,” says Reynaga as he looks out over the hives.

“I’m not going to make honey with these bees – they are just recovering. But at least I can rebuild the hive and put this thing behind me.”

Reynaga doubts he’ll put his bees in the Fresno County bee kill areas for almond pollination next year. “Even if I don’t put bees there again, I want this to stop,” says Reynaga.

“Because in the future, I don’t want this to happen to anybody else or me, down the road, in another place.”

At least six different beekeepers (or bee brokers) claimed losses of an estimated 8,000 bee hives in Fresno County.

Despite what happened in February, you can see from the green fuzzy nuts on almond trees that Fresno’s almond orchards were pollinated.

The county investigation is ongoing. It could be six months to a year before they issue a final report. 

Green nuts on almond trees in Fresno County

READ ARTICLE, LISTEN TO TWO RADIO BROADCASTS, AND LINK TO MORE RELATED STORIES: http://www.capradio.org/95104

 

California Considers Plant Warning Labels as Walmart & True Value Commit to Phasing Out Bee-Killing Pesticides

Pesticide Action Network North America  For Immediate Release May 3, 2017


Facing pressure from the pesticide lobby, California’s Pollinator Protection Act (SB 602) would create consistent and clear labels for seeds and plants pre-treated with neonicotinoid pesticides.

Sacramento, CA – As California considers legislation that would provide labels for seeds and plants that are pre-treated or pre-coated with bee-harming pesticides, two major retailers — True Value and Walmart — announced steps today to phase out the use of the products in their supply chain.  

“Despite pressure from the pesticide industry, gardeners and retailers are responding to the science. As two more major retailers commit to phasing out neonicotinoid pesticides on plants they sell, California legislators have an opportunity to create clear and consistent labels to allow consumers to purchase plants that are better for bees,” said Paul Towers, organizing director and policy advocate at PAN.  

California’s Pollinator Protection Act (Senate Bill 602, Allen-Wiener) would require mandatory labeling for any seed or plant that has been pre-coated or pre-treated with neonicotinoids, or “neonics.” But the legislation has faced significant opposition from pesticide manufacturers, and some industrial agricultural interest groups, that challenge both the science behind bee declines and the preponderance of evidence linking pollinator die-offs to pesticide exposure, among other factors.  

“It is great to see well-known retailers taking action to phase out products that include these harmful pesticides. I look forward to the passage of SB 602 so that California can enact a similar policy statewide,” said Senator Ben Allen (D-Santa Monica), a lead author of the bill, which is sponsored by Bee Smart California, a coalition of beekeepers, farmers, food and environmental organizations dedicated to protecting bees and other pollinators.  

Testing analyses conducted by PAN North America, Friends of the Earth, Center for Food Safety and the Pesticide Research Institute in 20132014 and 2016demonstrated the presence of bee-toxic neonics in more than half of bee-attractive flowers tested. The 2016 analysis found that 23 percent of flowers and trees tested nationally — and 15 percent tested in California — contain neonicotinoid insecticides at levels that can harm or kill bees. And all of the nursery plant samples where neonics were detected had the potential to harm or even kill bees.  

Large retailers Home Depot and Lowe's already made commitments to phase out use of these pesticides, and have also started to provide some form of labeling. Last year’s data demonstrated that these two companies are making progress toward that goal. With today’s news, True Value will phase out neonics on plants and products by 2018 and Walmart has already removed neonics from 80 percent of their flowering plants and nearly all of their products. 

“The actions taken by these national retailers show that there is broadening support for reducing and eliminating use of these awful pesticides. We need to continue to work to prevent the rapid and unprecedented collapse of bee colonies, which is threatening food security in the entire country, by enacting policies like SB 602,” said Scott Wiener (D-San Francisco), co-author of the bill.    

Greenhouse Grower’s 2016 State Of The Industry Survey found 74 percent of growers who supply mass merchants and home improvement chains said they would not use neonicotinoid insecticides in 2016. 

“With today’s announcement, fewer nurseries and garden stores are selling plants pre-treated with systemic neonicotinoid insecticides,” said Terry Oxford, a beekeeper with UrbanBeeSF. “Yet it’s still not possible for gardeners and landscapers to be sure that the seeds, plants and trees they select at the store will be safe for bees and other pollinators. Labels would provide that level of security. California legislators should support SB 602.”  

Bees and other pollinators, essential for every one in three bites of food we eat, are in great peril. The United Nations estimates that 40 percent of invertebrate pollinator species, including bees and butterflies, are on the brink of extinction. Research indicates that bee-harming neonicotinoids are a primary factor of declining populations. These insecticides have been responsible for several high profile bee kills from high doses of the pesticides, and a strong and growing body of science shows that neonics contribute to bees’ impaired reproduction, learning and memory, hive communications and immune response at doses far below those that are lethal.   

Contact: Paul Towers, PAN, 916-216-1082, ptowers@panna.org(link sends e-mail)

Pesticide Action Network (PAN) North America works to create a just, thriving food system. For too long, pesticide and biotech corporations have dictated how we grow food, placing the health and economic burdens of pesticide use on farmers, farmworkers and rural communities. PAN works with those on the frontlines to tackle the pesticide problem — and reclaim the future of food and farming.

http://www.panna.org/press-release/california-considers-plant-warning-labels-walmart-true-value-commit-phasing-out-bee?utm_source=web&utm_medium=fb&utm_campaign=bees

Scientists Say Agriculture is Good for Honey Bees

Phys.org    By Ginger Rowsey    May 2, 2017

In a recent study, researchers with the University of Tennessee Institute of Agriculture found the overall health of honey bees improved in the presence of agricultural production, despite the increased exposure to agricultural pesticides. Credit: Scott Stewart While recent media reports have condemned a commonly used agricultural pesticide as detrimental to honey bee health, scientists with the University of Tennessee Institute of Agriculture have found that the overall health of honey bee hives actually improves in the presence of agricultural production.

The study, "Agricultural Landscape and Pesticide Effects on Honey Bee Biological Traits" which was published in a recent issue of the Journal of Economic Entomology, evaluated the impacts of row-crop agriculture, including the traditional use of pesticides, on honey bee health. Results indicated that hive health was positively correlated to the presence of agriculture. According to the study, colonies in a non-agricultural area struggled to find adequate food resources and produced fewer offspring.

"We're not saying that pesticides are not a factor in honeybee health. There were a few events during the season where insecticide applications caused the death of some foraging bees," says Mohamed Alburaki, lead author and post-doctoral fellow with the University of Tennessee Department of Entomology and Plant Pathology (EPP). "However, our study suggests that the benefits of better nutrition sources and nectar yields found in agricultural areas outweigh the risks of exposure to agricultural pesticides."

Alburaki and fellow researchers established experimental apiaries in multiple locations in western Tennessee ranging from non-agricultural to intense agricultural production. Over the course of a year, colonies were monitored for performance and productivity by measuring colony weight, brood production and colony thermoregulation. Colony thermoregulation, or the ability to maintain an optimal temperature within a hive, is an important factor in brood development and the health of the resulting adult bees.

According to the study, hives located in areas with high to moderate agricultural vegetation grew faster and larger than those in low or non-agricultural areas. Researchers suggest the greater population sizes enabled better colony thermoregulation in these hives, as well.

Meanwhile, bees located in a non-agricultural environment were challenged to find food. Although fewer pesticide contaminants were reported in these areas, the landscape did not provide sustainable forage. In fact, during the observations, two colonies in the non-agricultural areas collapsed due to starvation.

Disruptions and fluctuations in brood rearing were also more notable in a non-agricultural environment. Interestingly, brood production was highest in the location that exhibited a more evenly distributed mix of agricultural production, forests and urban activity.

"One possible explanation for this finding could be the elevated urban activity in this location," says Alburaki. "Ornamental plantings around homes or businesses, or backyard gardens are examples of urban activity that increase the diversity of pollen in an area. Greater pollen diversity has been credited with enhancing colony development."

Researchers also evaluated trapped pollen from each colony for pesticide residues. Low concentrations of fungicides, herbicides and insecticides were identified, but at levels well below the lethal dose for honey bees. Imidacloprid was the only neonicotinoid detected, also at sub-lethal levels.

Agricultural pesticides, particularly neonicotinoids, are considered by some to be a key factor in declining honeybee populations. The UTIA study found that higher exposure to pesticides in agricultural environments did not result in measurable impacts on colony productivity.

"We train agricultural producers on careful selection and conscientious application of pesticides to reduce bee exposure," says Scott Stewart, Integrated Pest Management Specialist with UT Extension, "but it's becoming more clear that the influences of varroa mite and food availability are more important factors in honey bee health than agricultural pesticides."

 Journal reference: Journal of Economic Entomology

https://phys.org/news/2017-05-scientists-agriculture-good-honey-bees.html

Common Pesticide Hampers Honey Bee's Ability to Fly

Phys.org

A honey bee (Apis mellifera) is harnessed for study on a flight mill in biology professor James Nieh’s laboratory, UC San Diego. – Credit: Simone Tosi

A honey bee (Apis mellifera) is harnessed for study on a flight mill in biology professor James Nieh’s laboratory, UC San Diego. – Credit: Simone Tosi

A honey bee (Apis mellifera) is harnessed for study on a flight mill in biology professor James Nieh's laboratory, UC San Diego. Credit: Simone Tosi

Biologists at the University of California San Diego have demonstrated for the first time that a widely used pesticide can significantly impair the ability of otherwise healthy honey bees to fly, raising concerns about how pesticides affect their capacity to pollinate and the long-term effects on the health of honey bee colonies.

Previous research has shown that foraging honey bees that ingested neonicotinoid pesticides, crop insecticides that are commonly used in agriculture, were less likely to return to their home nest, leading to a decrease in foragers.

A study published April 26 in Scientific Reports by UC San Diego postdoctoral researcher Simone Tosi, Biology Professor James Nieh, along with Associate Professor Giovanni Burgio of the University of Bologna, Italy, describes in detail how the neonicotinoid pesticide thiamethoxam damages honey bees. Thiamethoxam is used in crops such as corn, soybeans and cotton. To test the hypothesis that the pesticide impairs flight ability, the researchers designed and constructed a flight mill (a bee flight-testing instrument) from scratch. This allowed them to fly bees under consistent and controlled conditions.

Months of testing and data acquisition revealed that typical levels of neonicotinoid exposure, which bees could experience when foraging on agricultural crops—but below lethal levels—resulted in substantial damage to the honey bee's ability to fly.

"Our results provide the first demonstration that field-realistic exposure to this pesticide alone, in otherwise healthy colonies, can alter the ability of bees to fly, specifically impairing flight distance, duration and velocity" said Tosi. "Honey bee survival depends on its ability to fly, because that's the only way they can collect food. Their flight ability is also crucial to guarantee crop and wild plant pollination."

Long-term exposure to the pesticide over one to two days reduced the ability of bees to fly. Short-term exposure briefly increased their activity levels. Bees flew farther, but based upon other studies, more erratically.

"Bees that fly more erratically for greater distances may decrease their probability of returning home," said Nieh, a professor in UC San Diego's Division of Biological Sciences.

This pesticide does not normally kill bees immediately. It has a more subtle effect, said Nieh.

"The honey bee is a highly social organism, so the behavior of thousands of bees are essential for the survival of the colony," said Nieh." We've shown that a sub-lethal dose may lead to a lethal effect on the entire colony."

Honey bees carry out fundamentally vital roles in nature by providing essential ecosystem functions, including global pollination of crops and native plants. Declines in managed honey bee populations have raised concerns about future impacts on the environment, food security and human welfare.

Neonicotinoid insecticides are neurotoxic and used around the world on broad varieties of crops, including common fruits and vegetables, through spray, soil and seed applications. Evidence of these insecticides has been found in the nectar, pollen and water that honey bees collect.

"People are concerned about honey bees and their health being impaired because they are so closely tied to human diet and nutrition," said Nieh. "Some of the most nutritious foods that we need to consume as humans are bee-pollinated."

Read more at: https://phys.org/news/2017-04-common-pesticide-honey-bee-ability.html#jCp