Pesticide Cocktail Can Harm Honey Bees

PHYS.ORG University of California at San Diego April 10, 2019

A honey bee collects pollen. Credit: James Nieh, UC San Diego

A honey bee collects pollen. Credit: James Nieh, UC San Diego

A recently approved pesticide growing in popularity around the world was developed as a "bee safe" product, designed to kill a broad spectrum of insect pests but not harm pollinators.

A series of tests conducted over several years by scientists at the University of California San Diego focused on better investigating the effects of this chemical. They have shown for the first time that Sivanto, developed by Bayer CropScience AG and first registered for commercial use in 2014, could in fact pose a range of threats to honey bees depending on seasonality, bee age and use in combination with common chemicals such as fungicides.

The study, led by former UC San Diego postdoctoral fellow Simone Tosi, now at ANSES, University Paris Est, and Biological Sciences Professor James Nieh, is published April 10 in Proceedings of the Royal Society B.

Pesticides are a leading health threat to bees. After years of growing concerns about systemic toxic pesticides such as neonicotinoids and their harm on pollinators, Sivanto was developed as a next-generation product.

Sivanto's "bee safe" classification allows it to be used on blooming crops with actively foraging bees. Currently, pesticides are approved for widespread use with only limited testing. Perhaps most importantly, the interactions between new pesticides and other common chemicals such as fungicides are not fully tested. Sivanto's product label does prohibit the pesticide from being mixed in an application tank with certain fungicides. However, bees can still be exposed to Sivanto and other chemicals (pesticide "cocktails") that are commonly used in adjacent crops or that persist over time.

Honey bee workers inside their nest. Credit: Heather Broccard-Bell

Honey bee workers inside their nest. Credit: Heather Broccard-Bell

Starting in 2016, after reviewing documents describing Sivanto's risk assessments, the scientists conducted several honey bee (Apis mellifera) studies investigating effects that were not previously tested, particularly the behavioral effects of chemical cocktails, seasonality and bee age. The scientists provided the first demonstration that pesticide cocktails reduce honey bee survival and increase abnormal behaviors. They showed that worst-case, field-realistic doses of Sivanto, in combination with a common fungicide, can synergistically harm bee behavior and survival, depending upon season and bee age. Bees suffered greater mortality—compared with control groups observed under normal conditions—and exhibited abnormal behavior, including poor coordination, hyperactivity and apathy.

The results are troubling, the researchers say, because the official guidelines for pesticide risk assessment call for testing in-hive bees, likely underestimating the pesticide risks to foragers. Honey bees have a division of labor in which workers that are younger typically work inside the colony (in-hive bees) and foragers work outside the colony. Foragers are therefore more likely to be exposed to pesticides.

"We found foragers more susceptible," said Nieh. "They tend to be older bees and therefore because of their age they can suffer greater harm."

The harmful effects of Sivanto were four-times greater with foragers than with in-hive bees, the UC San Diego study showed, threatening their foraging efficiency and survival. Both kinds of workers also were more strongly harmed in summer as compared to spring.

"This work is a step forward toward a better understanding of the risks that pesticides could pose to bees and the environment," said Tosi, a postdoctoral fellow and project manager at the Epidemiology Unit. According to the authors, the standard measurements of only lethal effects are insufficient for assessing the complexity of pesticide effects.

A honey bee forages on flower. Credit: Heather Broccard-Bell

A honey bee forages on flower. Credit: Heather Broccard-Bell

"Our results highlight the importance of assessing the effects pesticides have on the behavior of animals, and demonstrate that synergism, seasonality and bee age are key factors that subtly change pesticide toxicity," Tosi said. Cocktail effects are particularly relevant because bees are frequently exposed to multiple pesticides simultaneously.

"Because standard risk assessment requires relatively limited tests that only marginally address bee behavior and do not consider the influence of bee age and season, these results raise concerns about the safety of multiple approved pesticides, not only Sivanto," said Nieh, a professor in the Section of Ecology, Behavior and Evolution. "This research suggests that pesticide risk assessments should be refined to determine the effects of commonly encountered pesticide cocktails upon bee behavior and survival."

Sivanto is available in 30 countries in America, Africa, Asia and Europe, with 65 additional countries preparing to approve the product soon. Tosi points out that "because Sivanto was only recently approved, and no monitoring studies have yet investigated its co-occurrence with other pesticides after typical uses in the field, further studies are needed to better assess its actual environmental contamination, and consequent risk for pollinators."

"The idea that this pesticide is a silver bullet in the sense that it will kill all the bad things but preserve the good things is very alluring but deserves caution," said Nieh.
https://phys.org/news/2019-04-pesticide-cocktail-honey-bees.html

Explore further Pesticides and poor nutrition damage animal health

More information: S. Tosi et al. Lethal and sublethal synergistic effects of a new systemic pesticide, flupyradifurone (Sivanto ® ), on honeybees, Proceedings of the Royal Society B: Biological Sciences (2019). DOI: 10.1098/rspb.2019.0433

Journal information: Proceedings of the Royal Society B 

Provided by the University of California - San Diego https://phys.org/partners/university-of-california---san-diego/

Neonicotinoid Insecticides Can Serve As Inadvertent Insect Contraceptives

The Royal Society Biological Sciences    July 27, 2016

Abstract: There is clear evidence for sublethal effects of neonicotinoid insecticides on non-target ecosystem service-providing insects. However, their possible impact on male insect reproduction is currently unknown, despite the key role of sex. Here, we show that two neonicotinoids (4.5 ppb thiamethoxam and 1.5 ppb clothianidin) significantly reduce the reproductive capacity of male honeybees (drones), Apis mellifera. Drones were obtained from colonies exposed to the neonicotinoid insecticides or controls, and subsequently maintained in laboratory cages until they reached sexual maturity. While no significant effects were observed for male teneral (newly emerged adult) body mass and sperm quantity, the data clearly showed reduced drone lifespan, as well as reduced sperm viability (percentage living versus dead) and living sperm quantity by 39%. Our results demonstrate for the first time that neonicotinoid insecticides can negatively affect male insect reproductive capacity, and provide a possible mechanistic explanation for managed honeybee queen failure and wild insect pollinator decline. The widespread prophylactic use of neonicotinoids may have previously overlooked inadvertent contraceptive effects on non-target insects, thereby limiting conservation efforts. 

1. Introduction:Factors affecting reproductive success have a profound influence not only on a single individual's fitness, but on the dynamics of entire populations [1,2]. This principle provides a framework for pest control strategies that target reproduction. For example, modern-day agricultural practices frequently demand intensive insect pest management to ensure high-quality crops...

Read more: http://rspb.royalsocietypublishing.org/content/283/1835/20160506

Beekeeper, Farmers, and Public Interest Groups Sue EPA over Failed Oversight of Neonicotinoid-coated Seeds

Center for Food Safety    Press Release    January 6, 2016

Widespread and unregulated use of insecticide threatens bees, birds,
livelihoods and ecosystems

WASHINGTON, DC —Center for Food Safety, on behalf of several beekeepers, farmers and sustainable agriculture and conservation groups, filed a lawsuit today challenging the Environmental Protection Agency’s (EPA) inadequate regulation of the neonicotinoid insecticide seed coatings used on dozens of crops. EPA has allowed millions of pounds of coated seeds to be planted annually on more than 150 million acres nationwide. The lawsuit alleges the agency has illegally allowed this to occur, without requiring the coated seeds to be registered under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), without enforceable labels on the seed bags, and without adequate assessments of the serious ongoing environmental harm. 

“EPA’s actions surrounding neonicotinoid seed coatings have led to intensifying and destructive consequences. These include acute honey bee kills, as well as chronic effects to numerous species, nationwide water and soil contamination, and other environmental and economic harms,” said Peter Jenkins, attorney with Center for Food Safety. “This lawsuit aims to hold EPA accountable to dramatically reduce this harm in the future.” 

Neonicotinoids are a class of insecticides known to have acute and chronic effects on honey bees and other pollinator species and are considered a major factor in overall bee population declines and poor health. Up to 95 percent of the applied seed coating ends up in the surrounding air, soil and water rather than in the crop for which it was intended, leading to extensive contamination. 

“My honey farm business is not capable of surviving another three to five years if EPA chooses to 'drag out' the treated article exemption in the courts at the request of the pesticide industry instead of properly regulating these pesticides. People need pollinated food; somebody must stand up and say no to unregulated killing of pollinators,” said Jeff Anderson, beekeeper and the lead plaintiff in the case. 

“After experiencing a large loss of bees this spring due to corn planting ‘dust off,’ I believe that it is of critical importance that this defective product not be used as a prophylactic seed treatment,” said Bret Adee, owner of the largest commercial beekeeping operation in the country.

“As a beekeeper for over 50 years, I have lost more colonies of honey bees in the last ten years from the after effects of neonic seed coatings than all others causes over the first 40 plus years of my beekeeping operation,” said beekeeper David Hackenberg. “This not only affects my honey bees, but as a farmer it also affects my land and the health of my soil. It is time for EPA to accept the responsibility to protect not only our honey bees and other pollinators, but also our soil and our environment.” 

“Farmers rely on the crop pollination services of beekeepers to increase the yield of their crops. Farmers need clear, concise pesticide label guidelines in order to protect their crops and protect honey bees. Healthy relationships between soil and water, beekeepers and farmers, and beneficial insects and crops are essential to an affordable and sustainable food supply,” said Michele Colopy, program director at the Pollinator Stewardship Council, Inc. 

The cost-effectiveness of neonicotinoid seed coatings has been challenged in recent years, with numerous studies indicating that their near ubiquitous use is unnecessary — and making EPA’s disregard of their risks all the more harmful. Along with honey bees, wild bees and other beneficial insects are in serious decline, leading to reduced yields. Overuse of the insecticides threatens sustainable agriculture going forward. 

“I began to question the value of neonicotinoids after some side-by-side comparisons showed little if any yield advantage. Shortly after this I began to hear of the possible connection between neonicotinoids and their detriment to honey bees, and I stopped using them altogether,” said Kansas grain farmer Gail Fuller of Fuller Farms. 

“A single seed coated with a neonicotinoid insecticide is enough to kill a songbird.  There is no justification for EPA to exempt these pesticide delivery devices from regulation. American Bird Conservancy urges the agency to evaluate the risks to birds, bees, butterflies, and other wildlife,” said Cynthia Palmer, director of pesticides science and regulation at American Bird Conservancy.

"EPA can't bury its head in the sand any longer. Seed coatings are just the latest delivery device of pesticide corporations that pose a threat to pollinators and the food system," said Marcia Ishii- Eiteman, senior scientist at Pesticide Action Network. "Given widespread use and persistence of these bee-harming pesticides, it's time for EPA to fully and swiftly evaluate the impacts of seed coatings — and prevent future harm.”

EPA has also allowed several other similar systemic seed-coating insecticides onto the market and appears poised to approve additional coating products in the near future.

The plaintiffs in the case are beekeepers Jeff Anderson, Bret Adee, David Hackenberg, and Pollinator Stewardship Council, farmers Lucas Criswell and Gail Fuller, and public interest and conservation groups American Bird Conservancy, Center for Food Safety and Pesticide Action Network of North America.

Read at: http://www.centerforfoodsafety.org/issues/304/pollinators-and-pesticides/press-releases/4197/beekeeper-farmers-and-public-interest-groups-sue-epa-over-failed-oversight-of-neonicotinoid-coated-seeds#

Study Explores What We Know About How Neonicotinoids Affect Bees

 

 University of Guelph  November 2, 2015

An international group of pollination experts - including a University of Guelph professor - has published a second summary in as many years on the scientific evidence about the effects of neonicotinoid pesticides on bees.

The report was published this week in Proceedings of the Royal Society B.

"The extent to which neonicotinoid insecticides harm bees and other insect pollinators is one of the most contentious questions that environmental policymakers have to grapple with today," said U of G environmental sciences professor Nigel Raine, who holds the Rebanks Family Chair in Pollinator Conservation.

More than 400 studies have been published on the topic in the last decade, often presenting variable or conflicting findings, making it difficult for farmers and policy-makers to make evidence-based decisions, Raine said.

He served on a team of researchers whose first scientific review of the evidence was published in May 2014.

Since then, more than 80 new studies have appeared. The team was asked to update its findings by the chief scientific adviser of the United Kingdom government, which has banned the use of three neonicotinoid insecticides.

"Our aim was to act as honest brokers, providing an account of the evidence, its strengths and limitations, but without making any direct policy recommendations," Raine said.

The two reviews provide a comprehensive overview of current scientific understanding of neonicotinoid impacts on pollinators. Such information must be considered within the broader context of the many, interacting factors affecting pollinator health, Raine said.

He added that despite plenty of research on aspects of this topic, policymakers have only limited evidence on how pollinator populations are affected by neonicotinoid use and on how farmers will respond to usage restrictions.

"Insecticides are designed to kill insect pests. Bees, and many other important pollinators, are also insects that will be killed by insecticides if exposure levels are high enough," Raine said.

What's being debated is the extent to which field levels of exposure have impacts on pollinators, he said.

"It varies enormously depending on many factors, including the type of insecticide, how it is applied and which pollinator species you consider. Current evidence suggests that bumblebees and solitary bees are more severely affected by neonicotinoids than honeybees."

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Obama Pressed to Ban Bee-Killing Pesticide Before It's Too Late

Washington Examiner    By Paul Bedard   February 5, 2015

Honey bees are endangered by a new type of pesticide. APSeveral top environmental groups have joined with the honey bee industry to urgently demand that President Obama ban a pesticide many blame for the downfall of the world’s No. 1 food pollinator before it is too late.

Fearing that Obama’s Environmental Protection Agency is delaying action, the groups took the unusual step to press Obama directly in a letter that said inaction could jeopardize food supplies.

“We hope that you will prioritize action on this issue of vital importance to our food system, economy and environment and make saving bees a key piece of your legacy as president,” said the letter provided to Secrets.

It was signed by Trip Van Noppen, president of Earthjustice; Peter Lehner, executive director of the Natural Resources Defense Council; Erich Pica, president of Friends of the Earth U.S., and nine other green CEOs.

At issue is a new pesticide called “neonicotinoid.” Many in the bee industry blame them for the decade-long die-off of honey bees.

“If current rates of bee die-offs continue,” the letter says, “it is unlikely that the beekeeping industry will survive EPA’s delayed timeline, putting our agricultural industry and our food supply at serious risk.”

Obama has asked EPA to move on the issue, but the industry suspects the agency will call for more studies and delays in acting on the pesticide already banned in some countries.

Honey bee pollination is responsible for some $20 billion to the U.S. economy, and responsible for pollinating the nation’s nuts, fruits and veggies. But a mysterious killer has been wiping millions of hives and the pesticide is the top target of blame.

Read at: http://www.washingtonexaminer.com/obama-pressed-to-ban-bee-killing-pesticide-before-its-too-late/article/2559835

Bee Foraging Chronically Impaired by Pesticide Exposure: Study

The following is brought to us by the American Bee Journal     July 10, 2014

A study co-authored by a University of Guelph scientist that involved fitting bumblebees with tiny radio frequency tags shows long-term exposure to a neonicotinoid pesticide hampers bees' ability to forage for pollen.

The research by Nigel Raine, a professor in Guelph's School of Environmental Sciences, and Richard Gill of Imperial College London was published July 9 in the British Ecological Society's journal Functional Ecology.

The study shows how long-term pesticide exposure affects individual bees' day-to-day behavior, including pollen collection and which flowers worker bees chose to visit.

"Bees have to learn many things about their environment, including how to collect pollen from flowers," said Raine, who holds the Rebanks Family Chair in Pollinator Conservation, a Canadian first.

"Exposure to this neonicotinoid pesticide seems to prevent bees from being able to learn these essential skills."

The researchers monitored bee activity using radio frequency identification (RFID) tags similar to those used by courier firms to track parcels. They tracked when individual bees left and returned to the colony, how much pollen they collected and from which flowers.

Bees from untreated colonies got better at collecting pollen as they learned to forage. But bees exposed to neonicotinoid insecticides became less successful over time at collecting pollen.

Neonicotinoid-treated colonies even sent out more foragers to try to compensate for lack of pollen from individual bees.

Besides collecting less pollen, said Raine, "the flower preferences of neonicotinoid-exposed bees were different to those of foraging bees from untreated colonies."

Raine and Gill studied the effects of two pesticides – imidacloprid, one of three neonicotinoid pesticides currently banned for use on crops attractive to bees by the European Commission, and pyrethroid (lambda cyhalothrin) – used alone or together, on the behavior of individual bumblebees from 40 colonies over four weeks.

"Although pesticide exposure has been implicated as a possible cause for bee decline, until now we had limited understanding of the risk these chemicals pose, especially how it affects natural foraging behavior," Raine said.

Neonicotinoids make up about 30 per cent of the global pesticide market. Plants grown from neonicotinoid-treated seed have the pesticide in all their tissues, including the nectar and pollen.

"If pesticides are affecting the normal behavior of individual bees, this could have serious knock-on consequences for the growth and survival of colonies," explained Raine.

The researchers suggest reform of pesticide regulations, including adding bumblebees and solitary bees to risk assessments that currently cover only honeybees.

"Bumblebees may be much more sensitive to pesticide impacts as their colonies contain a few hundred workers at most, compared to tens of thousands in a honeybee colony," Raine said.

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What Happened to the Bees This Spring?

(The following is brought to us by the American Bee Journal.) 

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Randy Oliver, commercial beekeeper and scientist, has investigated and summarized the factors involved in colony losses this winter, including the contribution of pesticides. In this lengthy two-part analysis he has obtained many opinions from both commercial beekeepers and scientists.

By now, most everyone has heard that honey bee colonies died in massive numbers this winter. Reporter Dan Rather, in his newscast Buzzkill, showed unfortunate beekeepers, some of whom had lost half or more of their colonies, predicting gloom and doom for the bee industry. What were the causes of this year’s bee shortage? As Rather says, “Everyone has an opinion.” The question is whether those opinions are based upon fact! So let’s go over the events leading up to the bee supply debacle.

Setting the Stage
Nearly 800,000 acres of almond trees in California came into bloom this winter—the trees typically start flowering about Valentine’s Day, and the bloom lasts for only about two weeks. Almonds require cross fertilization between adjacent rows of varieties, and honey bees are trucked in from all over the country to do the job (roughly a million and a half colonies). Many large commercial beekeepers move their hives into California in November to overwinter in holding yards; others build them up on winter pollen flows in Florida or Texas, or hold them in temperature-controlled potato cellars until shortly before bloom. The hives are generally placed into the orchards about a week before the first flowers appear. There is virtually no forage in the orchards prior to, or after bloom in many areas.

The Lead Up
Two seasons ago there was also a shortage of bees in almonds, following the coldest January (2011) in 17 years (cold being a major stressor of wintering bee colonies). Beekeepers then replaced their deadouts with package bees and splits, thus starting a new generation of colonies, which tend to have lower varroa mite levels than established colonies. These colonies entered autumn 2011 in pretty good shape, and then enjoyed the fourth warmest January (2012) on record! As a result, there was the lowest rate of winter mortality in years, and plenty of bees for almonds in 2012.

I was curious as to whether the colony loss rate was linked to the use of neonicotinoid insecticides. There is no recent USDA data, so I went through the California Pesticide Use Reports (data available through 2010). I plotted the amount of imidacloprid applied to crops in California in the preceding year in red (the seed treatment clothianidin didn’t even make the top 100 list of pesticides applied). Although there appears to be a possible correlation from 2006 through 2009, the trends were reversed for 2010. I will be curious to add the 2011 data when it becomes available.

In March of 2012 I received a phone call from a California queen producer who had a prescient insight as to a potential brewing disaster. He was receiving calls for queen bees from Northern beekeepers whose bees had already grown to swarming condition due to the unseasonably warm spring weather.

The queen producer noted that such early brood rearing also meant early mite buildup, and predicted that since most Midwestern beekeepers treat for mites by the calendar, that they would unknowingly allow mites to build to excessive levels before treatment. This was strike one against the bees.

To continue reading, click here: What Happened to the Bees This Spring?

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