Bayer’s pesticides help mites to kill honeybees

This 14 March 2019 video says about itself:

France: Activists swarm Bayer HQ in Paris to protest bee deaths

Activists dressed as bees vandalised Bayer’s Paris headquarters on Thursday, during a protest against the corporation’s environmental impact and use of pesticides.

The protesters used fire extinguishers to spray yellow paint on the windows at the entrance of the building, and then poured a sticky liquid outside the front door, in what Association for the Taxation of Financial Transactions and for Citizens’ Action (ATTAC) spokesperson Annick Coupe called a symbolic gesture.

“You see bees, symbolically, came to tell Bayer that it’s killing them. And so they poured honey, always symbolically, and also poured a sticky product on the ground and brought it back to Bayer,” she said.

The international pharmaceutical corporation came under fire in 2016 after a study they conducted jointly with agricultural company Syngenta revealed their pesticide products caused severe harm to honeybees. The results of the survey were first left unpublished, until environmental group Greenpeace gained access to the study through freedom of information laws.

Coupe said the aim of the protest was “to show that it is possible to act against the multinational companies who contribute to harming our planet with impunity.”

When scientists blamed neonicotinoid pesticides produced by corporations like Bayer/Monsanto for massive dying of bees, sometimes the reaction was: Neonics do not kill bees. Varroa mites do.

However, in 2015 there already was this study: Interaction between Varroa destructor and [Bayer‘s] imidacloprid [pesticide] reduces flight capacity of honeybees.

Now, a new study …

From the University of Guelph in Canada:

Neonics hinder bees’ ability to fend off deadly mites

April 22, 2019

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.”

Today, scientists of the Institute of Bee Health of the University of Bern and the honeybee research association COLOSS have published an article in the peer-reviewed journal Scientific Reports that shows a synergistic time-lag interaction between the parasitic mite Varroa destructor and neonicotinoid insecticides reducing survival of winter honeybees, Apis mellifera. This article emphasizes the need to develop sustainable agricultural and apicultural schemes: here.

Many pesticides that have been banned or are being phased out in the EU, Brazil and China, are still widely used in the USA, according to a new study: here.

Prenatal exposure to the organophosphate pesticides has been linked to poorer cognition and behavior problems in children. A new study is one of the first to use advanced brain imaging to reveal how exposure can actually change brain activity. Teenagers estimated to have higher levels of prenatal exposure to organophosphates showed altered brain activity compared to their peers while performing tasks that require executive control, the study found: here.

12 thoughts on “Bayer’s pesticides help mites to kill honeybees

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