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."

A New Organic Acid Varroa Mite Medication

CATCH THE BUZZ    October 15, 2016

At its October meeting, the Committee for Medicinal Products for Veterinary Use (CVMP) of the European Medicines Agency (EMA) recommended the granting of a marketing authorization in the European Union (EU) for VarroMed (oxalic acid dihydrate / formic acid). This antiparasitic medicine treats the Varroa mite infestation in honey-bee colonies, which is considered to be the most significant parasitic health concern affecting honey bees worldwide.

Honey bees are essential for pollination of crops and wild plants in Europe. The European Commission estimates that pollinators, including honey bees, bumble bees and wild bees, contribute at least 22 billion euros each year to European agriculture and pollinate over 80% of crops and wild plants on the continent.

However, beekeepers around the world have reported losses of honey-bee colonies, which are considered to be caused by a combination of different factors such as habitat loss, climate change, pesticide use, and also diseases affecting bee health. A continued decline of these pollinators could lead to serious biological, agricultural, environmental and economic difficulties.

The main parasite affecting honey bees is the Varroa mite (Varroa destructor), an invasive species from Asia that has affected bee colonies worldwide. The Varroa mite feeds on the circulatory fluid of bees and brood (bee larvae) and can also contribute to the spread of viruses and bacteria.

VarroMed is intended to kill Varroa mites and is a liquid which is trickled onto bees in the hive. It contains as active substance a fixed combination of two organic acids, oxalic acid dihydrate and formic acid. Both substances have been known in veterinary medicine for a long time and are either naturally present in foods or accepted for use in foods. The medicine is not expected to pose a risk to human or animal health or the environment, if used according to the product information.

VarroMed is intended to be used as part of an integrated Varroa control programme, which includes not only treatment with medicines but also non-chemical techniques like queen trapping or drone brood removal. It can be used either as a single-dose treatment during the broodless period (winter treatment) or in the presence of brood (spring or autumn), which will usually require repeated treatments.

Treatment should only be given at times when honey is not produced by bees.

The effectiveness and safety of the product in the protection of honey bees against Varroa mites was tested in laboratory and field studies in different European climate conditions. VarroMed was effective in killing more than 80% of mites, which is below the effectiveness level of 90% recommended by the CVMP Varroa guideline. However, CVMP agreed that a lower level of 80% could be accepted when integrated Varroa control techniques are put in place. Repeated treatment of VarroMed might also result in increased bee mortality, and careful dosing is recommended to avoid overdosing.

The medicine has been classified as MUMS (minor use minor species/limited market), and, therefore, reduced data requirements apply, and these have been considered in the assessment. EMA’s MUMS policy aims to stimulate the development of new veterinary medicines for minor species and for diseases in major species for which the market is limited and that would otherwise not be developed under current market conditions.

The CVMP opinion will now be sent to the European Commission for the adoption of a decision on an EU-wide marketing authorization.

A Hardier Honeybee That Fights Back By Biting Back

npr The Salt    By Lou Blouin   January 11, 2016

Maryann Frazier, a researcher at Penn State's Center for Pollinator Research, checks on one of her experimental honeybee hives. Frazier is testing the effects
of pesticides on honeybee colonies.  
Lou Blouin for NPR

Keeping honeybees healthy has become a challenge for beekeepers. One main reason is a threat that has been wiping out bees since the late 1980s: the varroa mite.

"It's a parasitic mite that feeds on the blood of adult bees and on the brood. It also transmits virus, and it suppresses the immune system of the bees," explains Penn State honeybee expert Maryann Frazier.

It's basically like having a 6-pound house cat attached to your side, sucking the life out of you. These mites wiped out colonies across the world. And treatments were, and still are, pretty limited. In fact, the way most beekeepers treat bees for mites sounds a little crazy: They actually spray bees — which are, of course, insects — with low-dose insecticides. The hope is they'll kill the mites, but not the bees.

"But you can imagine how difficult it is to control a mite on a bee with a pesticide," Frazier says. Still, the strategy has worked well enough to at least give colonies a fighting chance.

But a co-op of about 100 beekeepers stretching from Michigan to Tennessee is trying a different approach. On his farm near Slippery Rock in Western Pennsylvania, beekeeper Jeff Berta lights a smoker to check on one of his all-star queen bees. This queen, he says, could be the future of honeybees in Pennsylvania.

"No. 18, there," Berta says, pointing to a queen with a little fluorescent yellow tag on it. "That little disc there with the '18' on it, we call those our NASCAR bees because they have numbers on them."

No. 18 is bit of a science experiment, funded with money from the USDA. This queen's mother is from a Vermont colony that survived disease and cold winters. And then Berta had her artificially inseminated by Purdue University scientists who were raising bees that demonstrated a unique, mite-fighting grooming behavior.

"The bees will take the mite and they will bite the legs and will chew on the mite," Berta says. "And if they bite a leg off of the mite, the mite will bleed to death. So the bees are actually fighting back. That's the type of genetic line we're after right now."

So now with every egg No. 18 lays, she passes on those leg-biting behaviors — making a colony that can rid itself of mites naturally, with no help from pesticides. It's a huge breakthrough.

But the breeding project can't end there. Because Berta can't artificially inseminate every queen, any descendants of No. 18 that turn into queens themselves will most likely just fly off and mate with any old drones within a few miles. That means if Berta's beekeeping neighbors don't have strong bees, too, they can easily dilute his carefully selected lines.

"So you can't produce a stock and say, 'Now I'm done! And that was it! Now we can sell it everywhere!' " says Penn State bee geneticistChristina Grozinger, who works with Berta. "You have to constantly re-select and constantly have to have people very interested in working as part of this effort."

That's why Berta and the co-op of beekeepers happily give eggs from their best colonies to their neighbors and swap queens to try out new genetics. It's all part of shifting the paradigm from a system where beekeepers simply buy new bees every year to a lasting neighborhood of bees that can slowly create real survivors.

"There really isn't any bee that laid the golden egg," Berta says. "Genetics with honeybees is more like a river, and the river is always changing."

Lou Blouin is a reporter for The Allegheny Front, a public radio program based in Pittsburgh that covers the environment.

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Feral Colonies...Good or Bad?

This message brought to us by CATCH THE BUZZ: Kim Flottum,  Bee Culture, The Magazine Of American Beekeeping, published by the A.I. Root Company. Twitter.FacebookBee Culture’s Blog

Source:  PlosOne  Published August 15, 2014

Catherine E. Thompson, Jacobus C. Biesmeijer, Theodore R. Allnutt, Stéphane Pietravalle, Giles E. Budge

Parasite Pressures on Feral Honey Bees  Feral Colonies Are Pathogen Reservoirs. A PlosOne Publication.

Feral honey bee populations have been reported to be in decline due to the spread of Varroa destructor, an ectoparasitic mite that when left uncontrolled leads to virus build-up and colony death. While pests and diseases are known causes of large-scale managed honey bee colony losses, no studies to date have considered the wider pathogen burden in feral colonies, primarily due to the difficulty in locating and sampling colonies, which often nest in inaccessible locations such as church spires and tree tops. In addition, little is known about the provenance of feral colonies and whether they represent a reservoir of Varroa tolerant material that could be used in apiculture. Samples of forager bees were collected from paired feral and managed honey bee colonies and screened for the presence of ten honey bee pathogens and pests using qPCR. Prevalence and quantity was similar between the two groups for the majority of pathogens, however feral honey bees contained a significantly higher level of deformed wing virus than managed honey bee colonies. An assessment of the honey bee race was completed for each colony using three measures of wing venation. There were no apparent differences in wing morphometry between feral and managed colonies, suggesting feral colonies could simply be escapees from the managed population. Interestingly, managed honey bee colonies not treated for Varroa showed similar, potentially lethal levels of deformed wing virus to that of feral colonies. The potential for such findings to explain the large fall in the feral population and the wider context of the importance of feral colonies as potential pathogen reservoirs is discussed.

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Pollinator Health and the USDA Blog

CATCH THE BUZZ  by Kim Flottum   May 14, 2014

Pollinator Health and the USDA. Who knew they had a blog?

This post is part of the Science Tuesday feature series on the USDA blog. Check back each week as we showcase stories and news from the USDA’s rich science and research portfolio.

You’ve probably heard that the honey bees in this country are in trouble, with about one-third of our managed colonies dying off every winter. Later this week, we will learn how the honey bees survived this winter. With severe weather in a number of areas in the U.S. this winter, a number of us concerned about bees will be closely watching the results.

While scientists continue work to identify all the factors that have lead to honey bee losses, it is clear that there are biological and environmental stresses that have created a complex challenge that will take a complex, multi-faceted approach to solve. Parasites, diseases, pests, narrow genetic diversity in honey bee colonies, and less access to diverse forage all play a role in colony declines. To confront this diverse mix of challenges, we require a mix of solutions – the odds are that we won’t find one magic fix to help our honey bees.

The parasitic mite Varroa destructor remains the major factor in overwintering colony declines. The varroa mite’s full name is Varroa destructor, and it is perhaps the most aptly named parasite ever to enter this country. An Asian native that arrived here in 1987, Varroa destructor is a modern honey bee plague. The problem is that varroa mites are becoming resistant to the miticides used to control them. And while there are folk remedies and organic treatments, none of those work as well. New treatments are in the pipeline, but another miticide can only be a short-term solution as the cycle of new treatment and new resistance continues.

USDA’s Agricultural Research Service (ARS) is looking to the genetics of both the mite and the honey bee for long-term solutions. ARS has put together a program to breed bees that can naturally resist varroa mites. For example, some bees have a propensity for nest cleaning and grooming behaviors, including aggressively kicking varroa-infested pupae out of the hive. The idea is to breed bees specifically to intensify such traits. ARS is also working on improving nation-wide epidemiological monitoring, finding genetic and/or biochemical disruptors and a host of other possibilities to help beekeepers and honey bees fight off varroa.

More important work like this ARS research could be supported by USDA in the future. As part of the current budget, USDA has requested $25 million to establish the Pollinator and Pollinator Health (PPH) Innovation Institute. The PPH would be administered by the USDA’s National Institute of Food and Agriculture (NIFA) and, with help from stakeholders, would be responsible for addressing the biological, environmental and management issues associated with the wide-spread decline of honey bees and other pollinators in our country. If established, the PPH will support the activities already identified in the joint USDA-Environmental Protection Agency action plan and build on current pollinator research and extension projects.

USDA’s dedicated scientists and researchers are working to help the honey bees. There are other pollinators, and some crops like corn, wheat, rice and even soybeans are mostly wind-pollinated, but the 90 or so crops that managed honey bees pollinate for farmers—berries, nuts, fruits and vegetables—are what add color, taste and texture to our diet. So USDA scientists are working to find a solution to varroa mites and other problems associated with honey bee health, so you continue to enjoy the bounty of US agriculture.

See more at: This post is part of the Science Tuesday feature series on the USDA blog. Check back each week as we showcase stories and news from the USDA’s rich science and research portfolio.

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The above message brought to us by CATCH THE BUZZ: Kim Flottom,  Bee Culture, The Magazine Of American Beekeeping, published by the A.I. Root Company. Twitter.FacebookBee Culture’s Blog.

Apivar ®- Amitraz Strips – receives exemption for Section 18

(The following is brought to us by CATCH THE BUZZ (Kim Flottum) Bee Culture, The Magazine of American Beekeeping, published by A.I. Root Company.)  

South Dakota today received a specific exemption under the provision of section 18 of FIFRA for the use of Apivar – Amitraz in a 3.33% formulation in plastic strip form – subject to condions and restrictions. Other individual states may apply for this exemption and receive a section 18 label for this varroa control product.

Apivar is an unregistered product (EPA File Symbol 87243-R) formulated as a sustained release plastic strip impregnated with 3.33% amitraz (0.5 g active ingredient per strip) manufactured by WYJOLAB for Veto-Pharma S.A.. All applicable directions, restrictions, and precatuons on the product label as well as the section 18 use directions submitted with an updated application must be followed. A mazimum of 500,000 strips treated with amitraz may be used.

Label instructions are more detailed, but in brief….To control varroa, remove honey supers before application of Apivar, use 2 strips per brood chamber with a minimum distance of 2 frames between strips. Bees should walk on the strips. Leave strips in the boxes for 42 days, then remove. Reposition as needed so bees stay in contact, then leave for 14 more days. Strips must be removed after a maximum of 56 days.

A maximum of 2 treatments, spring and fall, may be made per year if varroa mite infestiation reachs treatment thresholds.  Honey supers cannot be on when strips are used, and cannot be replaced until 14 days after strip removal. Protecitve gloves are required. 

Here’s an important point…. 

Total residues of amitraz in honey and beeswax are not expected to exceed 0.2 and 9 ppm, respectively.

The exemption will expire in your state, assuming your state applies for this section 18, one year from date of authorization.

Currently, a section 3 registration is under review in South Dakota.

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