Neonics Hinder Bees' Ability to Fend Off Deadly Mites

Science Daily Story Source: University of Guelph April 22, 2019

The self-grooming behavior of wild honey bees like these can be affected by pesticides.  Credit: University of Guelph

The self-grooming behavior of wild honey bees like these can be affected by pesticides. Credit: University of Guelph

A University of Guelph study is the first to uncover the impact of neonicotinoid pesticides on honey bees' ability to groom and rid themselves of deadly mites.

The research comes as Health Canada places new limits on the use of three key neonicotinoids while it decides whether to impose a full phase-out of the chemicals.

Published in the Nature journal Scientific Reports, the study revealed that when honey bees are infected with varroa mites and then regularly exposed to low doses of a commonly used neonicotinoid called clothianidin, their self-grooming behaviour drops off.

Without that self-grooming, bees are susceptible to mites that can also carry viruses that can quickly kill, said lead author Nuria Morfin Ramirez, who completed the research along with Prof. Ernesto Guzman, School of Environmental Sciences, as part of her PhD.

"When bee colonies began to collapse years ago, it became clear there wasn't just one factor involved, so we were interested in whether there was an interaction between two of the main stressors that affect bees: varroa mites and a neurotoxic insecticide, clothianidin," said Morfin.

"This is the first study to evaluate the impact on the grooming behaviour of bees."

Neonicotinoids, or "neonics," are the most commonly used insecticides in Canada. They are coated on canola and corn seeds or sprayed on fruit and vegetable plants and trees. But they have also been linked to honey bee colony collapses.

Varroa mites are also contributing to colony collapses and have been associated with more than 85 per cent of colony losses.

The mites kill bees by slowly feeding off their body fat and hemolymph (blood), and can also transmit a virus called deformed wing virus (DWV). One of the only ways bees can protect themselves is to groom aggressively and brush the mites off.

The researchers wanted to know whether the two stressors of pesticide exposure varroa mites were working together to contribute to bee deaths. The research team used bees from U of G's Honey Bee Research Centre and exposed them to a widely used neonic clothianidin, either on its own or along with varroa mites.

They experimented with three doses of clothianidin, all similar to what the bees would experience while feeding on flower nectar of neonic-treated crop fields, but all low enough to be considered sublethal.

"What we found was a complicated interaction between the mite and the pesticide that decreased the proportion of bees that groomed intensively, and affected genes associated with neurodegenerative processes," Morfin said.

Bees exposed to medium level doses of the neonic showed no changes in grooming behaviour, but when they were also introduced to varroa mites, the proportion of bees that groomed intensively was 1.4 times lower compared to the bees exposed to clothianidin alone.

When exposed to the lowest dose of the pesticide, the proportion of bees that groomed significantly dropped. The lowest dose was also linked to an increased level of deformed wing virus -- an effect not seen at the higher doses.

"These results showed a complex and non-additive interaction between these two stressors," said Guzman. "This study highlights the importance of reducing stressors that bees are exposed to, to reduce the risk of disease and consequently colony mortality."

https://www.sciencedaily.com/releases/2019/04/190422112818.htm

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

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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Guelph Scientists One Step Closer to Inhibiting Destructive Bee Disease

The Globe and Mail    By Eric Atkins  December 16, 2014

The honeybees responsible for pollinating one-third of the food we eat face a host of threats, from bloodsucking mites and viruses to pesticides and climate change.

But researchers at the University of Guelph have taken a big step toward fighting the most destructive and widespread killer of honeybee larvae, a disease known as American foulbrood.

For the first time, scientists have identified a toxin released by the pathogen, and come up with a drug that could stop the disease that is prevalent in North America, Europe and other parts of the world.

“What we’ve found is an important factor that we can inhibit in this honeybee disease,” said Rod Merrill, a Guelph biochemist and co-author of the study to be published in the December issue of the Journal of Biological Chemistry.

American foulbrood, named for the smell of infected hives and the country in which it was first identified more than a century ago, is spread easily among honeybee colonies by spores carried by adult bees. The spores are eaten by larvae, which die but also spread millions more spores into the hive.

“The next generation is kaput. It’s not toxic to the adults, but that ultimately destroys the hive,” Prof. Merrill said in an interview. “And then what happens is robber bees go into the hive and steal the honey, which is contaminated with the bacterial spores, and then they drag it over to their hive, so it just proliferates.”

Hives infected with the bacteria quickly fail, and beekeepers must burn the hive and all associated equipment to ensure the spores are destroyed.

There is no cure for American foulbrood. Antibiotics used to control the disease have proven ineffective as resistant strains have developed.

Field tests to be conducted on hives in the spring will show whether the drug is effective at controlling American foulbrood, said Prof. Merrill, who began the research more than two years ago.

The drug that could treat the disease is not an antibiotic, but an anti-virulence compound that controls the toxin that kills the larvae but does not prompt the bacteria to mutate by threatening their survival.

“Research takes a long time. So right at this moment I can’t say what the impact will be in treating American foulbrood,” Prof. Merrill said. “However, I can say it’s going in the right direction that we need to characterize the toxins produced by the organism that causes American foulbrood or the impending crisis for the honeybee is going to get worse.”

Long winters, virus-bearing varroa mites and pesticide exposure have contributed to declines in honeybee populations in North America and Europe. In Ontario, declining honey production and mounting costs of replacing dead bees have been blamed in part on neonicotinoid pesticides that are used to grow corn and soybeans.

In response, the Ontario government recently said it plans to impose rules that would reduce the use of the systemic pesticide by 80 per cent by 2017. Farmers who plant seeds treated with neonics would have to show their fields are susceptible to grubs, worms and other yield-destroying pests.

The move is opposed by the chemical companies that sell the pesticide-treated seeds and the Grain Farmers of Ontario, which says the restrictions will take away an important tool farmers use to protect their harvests.

A new poll of 1,000 Ontarians shows nearly 80 per cent support the provincial government’s plans to restrict the use of neonics, which scientists say impair bees’ foraging abilities and contribute to colony failure.

The poll, released by the Canadian Association of Physicians for the Environment, Friends of the Earth Canada and the Ontario Beekeepers’ Association, found support for the restrictions was strongest (85 per cent) in Southwestern Ontario, the heart of Canada’s corn-and-soybean region. Support was weakest, 60 per cent, in the central part of the province.

“Our food security depends on healthy pollinators,” said Gideon Forman of the Canadian Association of Physicians for the Environment. “Ontarians are aware of the current crisis and want the government to take action to protect bees.”

Read at:  http://www.theglobeandmail.com/technology/science/scientists-in-guelph-come-one-step-closer-to-saving-the-bees/article22098146/

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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Bees Capable of Learning Feats with Tasty Prize in Sight

  Science Daily     Source: University of Guelph  3/18/14 

Summary:
Bumblebees are capable of some remarkable learning feats, especially when they might get a tasty reward, according to two studies. In the first study, the researchers found bees capable of learning to solve increasingly complex problems, an example of scaffold learning. In a second study, the researchers found bees learned by watching and communicating with other bees, a process called social learning.

They may have tiny brains, but bumblebees are capable of some remarkable learning feats, especially when they might get a tasty reward, according to two studies by University of Guelph researchers.

PhD student Hamida Mirwan and Prof. Peter Kevan, School of Environmental Sciences, are studying bees' ability to learn by themselves and from each other.

In the first study, published in February in Animal Cognition, the researchers found bees capable of learning to solve increasingly complex problems.

The researchers presented bees with a series of artificial flowers that required ever-more challenging strategies, such as moving objects aside or upwards, to gain a sugar syrup reward.

When inexperienced bees encountered the most complex flower first, they were unable to access the syrup reward and stopped trying. Bees allowed to progress through increasingly complex flowers were able to navigate the most difficult ones.

"Bees with experience are able to solve new problems that they encounter, while bees with no experience just give up," said Mirwan.

She and Kevan consider the study an example of scaffold learning, a concept normally restricted to human psychology in which learners move through increasingly complex steps.

In a second study recently published in Psyche,the researchers found bees learned by watching and communicating with other bees, a process called social learning.

Mirwan made artificial flowers requiring the bees to walk on the underside of a disk to get a sugar syrup reward. These experienced bees foraged on the artificial flowers for several days until they became accustomed to feeding at them.

To see whether other bees could learn from the experienced foragers, Mirwan confined inexperienced bees in a mesh container near the artificial flowers where they could observe the experienced bees. When the naïve bees were allowed to forage on the artificial flowers, they took just 70 seconds to get the reward.

Control bees that had not observed the experienced bees could not access the syrup.

"Social learning in animals usually involves one individual observing and imitating another, although other kinds of communication can also be involved," said Mirwan.

"They could try for up to 30 minutes, but most gave up before then."

In a final test, Mirwan placed experienced bees in a hive with naive bees. When the naive bees were allowed to forage on the artificial flowers, they gained the syrup in just 3.5 minutes.

Behavioural scientists usually assume that observation and imitation are at the heart of social learning, but social insects such as bees can also transmit information through touch, vibration and smell.

The researchers said the communication method used by the bees is still a mystery.

"We can't quite explain how bees that had never even seen an artificial flower were able to become adept so quickly at foraging on them, but clearly some in-hive communication took place," said Kevan.

"It suggests that social learning in bumblebees is even more complex than we first expected."

Read:  http://www.sciencedaily.com/releases/2014/03/140318142529.htm

Urban Bees Using Plastic to Build Hives

Science Daily   2/11/12

Once the snow melts, bees will be back in business -- pollinating, making honey and keeping busy doing bee things. For at least two urban bee species, that means making nests out of plastic waste. A new study reveals that some bees use bits of plastic bags and plastic building materials to construct their nests.

A new study by a University of Guelph graduate and a U of G scientist reveals that some bees use bits of plastic bags and plastic building materials to construct their nests. The research was published recently in the journal Ecosphere.

It's an important discovery because it shows bees' resourcefulness and flexibility in adapting to a human-dominated world, says lead author Scott MacIvor, a doctoral student at York University and a 2008 U of G graduate.

"Plastic waste pervades the global landscape," said MacIvor. Although researchers have shown adverse impacts of the material on species and the ecosystem, few scientists have observed insects adapting to a plastic-rich environment, he said.

"We found two solitary bee species using plastic in place of natural nest building materials, which suggests innovative use of common urban materials.

Figuring out that the bees were...

Read more... http://www.sciencedaily.com/releases/2014/02/140211103340.htm

Corn Dust Research Consortium (CDRC) Calls for Cooperative Measures to Support Honey Bees, Beekeepers, and Farmers

Bee Culture's CATCH THE BUZZ by Kim Flottum   1/30/14

R. Thomas (Tom) Van Arsdall, Director of Public Policy

The non-profit Pollinator Partnership (P2) today released the 2013 Preliminary Report and Provisional Recommendations of the Corn Dust Research Consortium (CDRC), a multi-stakeholder initiative formed to fund research with the goal of reducing honey bee exposure to fugitive dust emitted from planter fan exhaust during mechanical planting of treated corn seed. The report can be found at http://www.pollinator.org/PDFs/CDRCfinalreport2013.pdf with provisional recommendations starting on page 23.

The CDRC participating organizations include the American Seed Trade Association, the American Honey Producers Association, the American Beekeeping Federation, the Association of Equipment Manufacturers, Bayer CropScience, the Canadian Honey Council, the Farm Equipment Manufacturers Association, the National Corn Growers Association, the Pollinator Partnership, Syngenta, and the University of Maryland. These organizations came together to fund and oversee research projects in 2013 to better understand ideas for mitigating risks to honey bees from exposure to fugitive dust emitted from fan exhaust from machinery during corn planting.

The CDRC funded three research teams, led by Dr. Reed Johnson of Ohio State University, Dr. Mary Harris of Iowa State University, and Dr. Art Schaafsma, University of Guelph on behalf of the Grain Farmers of Ontario. It is hoped that the preliminary results and provisional recommendations will inform best practices for the 2014 planting season. Additional research in subsequent seasons will be needed to replicate and...

Read more at: http://home.ezezine.com/1636/1636-2014.01.30.16.10.archive.html

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