Thread: Neonicotinoid pesticides tied to crashing bee populations, 2 studies find

Neonicotinoid pesticides tied to crashing bee populations, 2 studies find

AAAS / ScienceA bee with a transmitter glued to its back was one of the specimens in a study that used the radio technology to track what happened to bee colonies exposed to a widely used pesticide.

By Miguel Llanos, msnbc.com

A widely used farm pesticide first introduced in the 1990s has caused significant changes to bee colonies and removing it could be the key factor in restoring nature's army of pollinators, according to two studies released Thursday.

The scientists behind the studies in Europe called for regulators to consider banning the class of chemicals known as neonicotinoid insecticides. In the U.S., the Environmental Protection Agency told msnbc.com that the studies would be incorporated into a review that's currently under way.

A pesticide trade group questioned the data, saying the levels of pesticide used were unrealistically high, while the researchers said the levels used were typical of what bees would find on farms.

"Our study raises important issues regarding pesticide authorization procedures," stated Mikael Henry, co-author of a study on honey bees. "So far, they mostly require manufacturers to ensure that doses encountered on the field do not kill bees, but they basically ignore the consequences of doses that do not kill them but may cause behavioral difficulties."

"There is an urgent need to develop alternatives to the widespread use of neonicotinoid pesticides on flowering crops wherever possible," added the authors of the second study on bumble bees.

Last week, a coalition of environmental groups and beekeepers asked the EPA to suspend the use of the pesticide, which is widely used in flowering crops like corn, sunflower and cotton to combat insects.

The studies are the first to go outside the lab and into the fields, where the experts said they detected how the pesticide impacts bees as they collect pollen and pollinate flowers and crops.

Honey bee populations have been crashing around the world in recent years, and pesticides have been suspected, along with other potential factors such as parasites, disease and habitat loss, in what's known as Colony Collapse Disorder. In the U.S., some beekeepers in 2006 began reporting losses of 30-90 percent of their hives, according to the U.S. Department of Agriculture.

Combating Colony Collapse Disorder is hardly an esoteric exercise. The USDA notes that "bee pollination is responsible for $15 billion in added crop value, particularly for specialty crops such as almonds and other nuts, berries, fruits, and vegetables.

"About one mouthful in three in the diet directly or indirectly benefits from honey bee pollination," it adds.

Published in the peer-reviewed journal Science, one study by British scientists looked at honey bees and the other by French scientists examined bumble bees, which unlike honey bees live in the wild but also are key pollinators.

In the bumble bee study, researchers concluded that colonies treated with nonlethal levels of the pesticide "had a significantly reduced growth rate and suffered an 85% reduction in production of new queens" compared to colonies without the pesticide.

"It was quite massive," researcher Penelope Whitehorn said of the reduction at a press conference Thursday. (Click here for audio of the news conference.)

"Bumble bees have an annual life cycle and it is only new queens that survive the winter to found colonies in the spring," the authors noted. "Our results suggest that trace levels of neonicotinoid pesticides can have strong negative consequence for queen production by bumble bee colonies under realistic field conditions, and this is likely to have a substantial population-level impact."

In the honey bee study, radio transmitters were attached to the back of bees to see how they foraged in conditions with and without the pesticide.

The pesticide, the researchers concluded, impaired the homing ability of bees and exposed bees were two to three times more likely to die while away from the hive. That "high mortality ... could put a colony at risk of collapse" within a few weeks of exposure, especially in combination with other stressors, they noted.

"We were actually quite surprised by the magnitude," Henry told reporters.

CropLife America, a pesticides trade group, said in a statement that the studies "fail to account for the many real-world factors that impact bee and colony health, and the researchers used unrealistic pesticide dose levels that are not commonly found in practical field situations in agriculture."

A leading U.S. researcher said the honey bee study "did use a higher dose than we have seen in pollen and nectar."

That study is "not fatally flawed," added Jeff Pettis of the USDA's Bee Research Laboratory, "but the higher dose must be considered as being a factor in why they saw the loss of bees."

"The bumble bee study, however, used a very realistic dose and the effect on reproduction was the major

finding," he told msnbc.com. "The bumble bee study was very convincing in my opinion in being realistic and showing a significant impact on reproduction."

In the honey bee study, the authors said they tested the bees at an "intensive cereal farming system" in France and used sublethal amounts ofthiamethoxam, "a recently marketed neonicotinoid substance currently being authorized in an increasing number of countries worldwide for the protection of oilseed rape, maize and other blooming crops foraged by honey bees."

The EPA, contacted by msnbc.com, said it has "begun reviewing the two studies ... and they will be considered" as part of an ongoing process that reviews chemicals. Non-EPA scientists will weigh in at a special meeting in the fall, it added.

The prevailing view among most scientists and regulators is that "complex interactions among multiple stressors" are to blame, the EPA stated. "While our understanding of the potential role of pesticides in pollinator health declines is still progressing, we continue to seek to learn what regulatory changes, if any, may be effective."

U.S. News - Neonicotinoid pesticides tied to crashing bee populations, 2 studies find

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Scientists call for global ban on bee-killing pesticides

By Damian Carrington, The Guardian
Wednesday, April 11, 2012 10:06 EDT



Topics: honey bees ♦ pesticides

How valuable are bees? In the UK, about £1.8bn a year, according to new research on the cost of hand-pollinating the many crops bees service for free. If that sounds a far-fetched scenario, consider two facts.

First, bees are in severe decline. Half the UK’s honey bees kept in managed hives have gone, wild honey bees are close to extinction and solitary bees are declining in more than half the place they have been studied.

Second, hand-pollination is already necessary in some places, such as pear orchards in China, and bees are routinely trucked around the US to compensate for the loss of their wild cousins.

The new figure comes from scientists at the Reading University and was released by Friends of the Earth to launch their new campaign, Bee Cause. Paul de Zylva, FoE nature
campaigner, said: “Unless we halt the decline in British bees our farmers will have to rely on hand-pollination, sending food prices rocketing.”

So what’s the problem? The losses of flowery meadows that feed wild bees is a factor, as are the parasites and diseases that can kills hives. But a third factor has now moved to the centre of the debate: pesticides called neonicotinoids. The insect nerve-agents are used as seed dressings, which means they end up in every part of the crop they protect, including pollen and nectar.

Two landmark studies, conducted in field conditions, published in Science in March clearly implicated sub-lethal doses of the pesticides with increases in disappeared bees and crashes in the number of queens produced by colonies. Then on 5 April, another study was released, showing the pesticides can cause colony collapse disorder (CCD), the name given to the ghostly hives from which bees have vanished.

“The data, both ours and others, right now merits a global ban,” said Chensheng Lu, in the department of environmental health at Harvard University, and who led the the CCD study. “I would suggest removing all neonicotinoids from use globally for a period of five to six years. If the bee population is going back up during the after the ban, I think we will have the answer.”

Lu told me he was in no doubt about the result of his work, which tested the effect of a very widely used neonicotinoid called imidacloprid, which is registered for use on over 140 crops in 120 countries. “Our study clearly demonstrated that imidacloprid is responsible for causing CCD, and the survival of the control hives that we set up side-by-side to the pesticide-treated hives augments this conclusion.” He said the hives were initially healthy, were placed in a natural foraging environment and that the doses of the pesticide the bees were exposed to were realistic.

After 12-weeks of dosing, all the bees were alive, but after 23 weeks, 15 of the 16 treated hives had died – but none of the untreated control hives. Lu said the dead hives were virtually empty, as is seen with CCD, and in contrast to the impact of parasites or disease, which leave hives littered with dead bees.


The leader of one of the Science studies, Mickaël Henry, at INRA in Avignon, France, agreed with Lu that action is urgently needed on neonicotinoids. “We now have enough data to say authorisation processes must take into account not only the lethal effects, but also the effects of non-lethal doses.” In other words, testing whether the pesticide use kills bees stone dead immediately is no longer good enough, given the hard evidence now available that sub-lethal doses cause serious harm.

So what does the UK government have to say? To date, it has agreed with the neonicotinoid manufacturers that there is no evidence that the pesticides used at normal levels cause harm. A statement on Wednesday from an environment department spokeswoman suggests no change: “The UK has a robust system for assessing risks from pesticides. We keep all the science under review and we will not hesitate to act if we need to.”

What more does it need? The new data makes it impossible to maintain this position, whatever vested interests are at stake. It is 50 years since Rachel Carson published Silent Spring, which documented the devastation wrought by pesticides in the US. What better time to act?

© Guardian News and Media 2012
Photo of bees via Aleksandar Mijatovic/Shutterstock.com

Scientists call for global ban on bee-killing pesticides | The Raw Story