Tag Archives: neonicotinoids

Any amount of neonicotinoids can be harmful for bees, study finds

Neonicotinoids, one of the most widely-used types of pesticides, can severely affect bees even when applied well below the label rate, according to a new study. It was surprising even to the researchers to see how much damage neonicotinoids could do. 

Image credit: Flickr / Caroline Legg

“Neonicotinoids are often used on food crops as a seed treatment,” UC Riverside entomologist and lead study author Jacob Cecala said in a statement. “But they’re usually applied in higher amounts to ornamental plants for aesthetic reasons. The effects are deadly no matter how much the plants are watered.”

Neonicotinoids are a type of pesticide very common in agriculture but with a clear negative effect on the health of bees, causing the death of whole swarms. For years, beekeepers have been warning over their effect, pushing for stronger regulations. Fewer bees in the world can lead to the loss of biodiversity and even affect our food supply.

There are three main neonicotinoids currently in use: imidacloprid, clothianidin, and thiamethoxam. Two are made by Bayer (which owns Monsanto) and the other by Syngenta. These compounds are used to coat seeds, as a spray on citrus trees, and as a soil drench of annuals. Soybeans and corn are the main crops on which neonicotinoids are used.

A European Union moratorium has restricted the application of three neonicotinoids to crops since 2013. Meanwhile, in the US the Environmental Protection Agency (EPA) banned last year 12 products containing neonicotinoid, leaving 47 neonicotinoid-based products on the market. In 2017, beekeepers in the US reported losing about 40% of their hives.

Dangerous pesticides

For the study, the researchers from UC Riverside focused on the application of neonicotinoids in potted ornamental plants, which represent potent and acute sources of exposure to the toxin for most bees. Most previous studies focused on the use of pesticides in food crops like canola, in which they are applied at low doses. 

The researchers raised bees on flowering native plants in pots that either received a lot of watering or a little. The plants were chosen based on their popularity, drought tolerance to ensure blooming even without a lot of water and their attractiveness to bees. While water decreased the strength of the pesticide, the negative effects on bees were still observed. 

The first time they tried the experiment, the researchers used the concentration of insecticide recommended on the product label. All the bees died in a matter of days. They ran the experiment a second time and despite using a third of the recommended dose, they still found negative effects on the reproduction and overall fitness of the bees. 

“It’s not as simple as ‘don’t use pesticides’ — sometimes they’re necessary,” Cecala said in a statement. “However, people can look for a different class of insecticide, try to apply them on plants that aren’t attractive to bees, or find biological methods of pest control.”

The study was published in the journal Proceedings of the Royal Society B: Biological Sciences


Insecticides and low floral diversity are driving bumblebees into the ground

Bumblebee queens are finding it harder and harder to cope — and, as they go, so do their colonies.


Image credits Tim Hill.

It’s not easy being royalty, at least not if you’re a bumblebee. Every year after emerging from hibernation, bumblebee queens must prepare the nest, lay eggs, and rear larvae — all on their own. Needless to say, it’s a highly demanding job. And, if they fail to live up to it, there won’t be any colony. New research worryingly shows that we might be putting more on the plate of these single moms than they can shoulder.

Queen of an empty castle

The research team at the University of California Riverside reports that exposure to widely-used insecticide substances, along with poorer diets caused by reduced availability of flowers, are taking a toll on the queens. Since each must get the colony up and running by herself, the team is worried this effect will have drastic consequences on the bumblebees — a critical pollinator that’s already wavering.

Bumblebees play a key role in both natural and agricultural settings. They’re fuzzy and fast, meaning they can carry quite a lot of pollen around. They’re not picky, meaning they’ll pollinate virtually every flower they can get to. A lot of our crops today — from tomatoes to blueberries — heavily depend on bumblebees as the main pollinator species. However, unlike honey bees, bumblebee colonies need to be reset each year, starting from a single queen — making the species incredibly vulnerable during this phase.

“Queens are probably already a bottleneck for bumblebee population dynamics,” said Hollis Woodard, an assistant professor of entomology at the University of California Riverside and paper first author.

“If a queen dies because of exposure to humanmade stressors, then a nest full of hundreds of important pollinators simply won’t exist.”

Previous research has linked insecticide use — including neonicotinoids, one of the most widely-used of such compounds — with a decline in pollinator numbers. Neonicotinoids are usually applied to seeds, the team writes, but they can seep into the soil. And that’s where bumblebee queens hibernate. The compounds can also accumulate in the mature plant’s tissues, including its pollen and nectar.

Another factor that’s impacting bumblebees is declining floral diversity. This is mostly due to the use of land for agriculture and broader global changes that affect ecosystem integrity, such as climate change. According to the team, bumblebees “collect pollen from a wide variety of plant species,” and there is evidence that they need a mixed diet. Dining on pollen from a single species just doesn’t cut it for the fuzzy insects.

The team tested the effects of temporary and sustained exposure to imidacloprid — a neonicotinoid — on a queen’s mortality, activity, and ability to set-up a healthy nest. They also ran the test to see what effect a single source of pollen would have on those factors.

Their results showed that queens were significantly less active and six times more likely to die after sustained exposure to the pesticide (37 days). A shorter exposure (17 days) somewhat reduced these effects. More worryingly, even if the queens survived, they produced only a third of the eggs and a quarter of the larvae of untreated queens.

Monofloral pollen didn’t have such drastic effects, but it still noticeably influenced a queen’s activity levels and the size of its brood.

“Ours is the first study to explore the impact of multiple stressors on bumblebee queens during an understudied but important phase of their lives. It joins a small but growing body of research suggesting there are unique effects on queens that can have dramatic consequences for future generations,” Woodard said.

Woodard believes the findings are grounds for U.S. policymakers to reconsider the use of neonicotinoids. The EU has already set a ban on the use of these substances, to come into effect by the end of 2018.

Since bumblebees and pollinators on a whole are so immensely valuable to humanity, I hope Woodard’s warning is heeded.

The paper “Effects of neonicotinoid insecticide exposure and monofloral diet on nest-founding bumblebee queens” has been published in the journal Proceedings of the Royal Society B: Biological Sciences.

It’s official: pesticides are harming the bees

A new, comprehensive report from European scientists confirms what many researchers have already been warning about: a class of pesticides called neonicotinoids poses a danger to wild bees and managed honey bees. The report analyzed over 1,500 studies on the issue.

“This report certainly strengthens the case for further restrictions on neonicotinoid use,” entomologist Dave Goulson of the University of Sussex in Brighton, U.K., said in a statement.

Bees are going through a dramatic decline. Global populations are dwindling, we don’t know why, and we’re not exactly sure how to stop it. But more and more evidence is mounting that this is connected to neonicotinoids, the world’s most popular class of insecticides.

Neonicotinoids (also called neonics) are used to coat seeds to protect them when they are sown. They’re essentially nerve agents. When the seed germinates, it spreads the pesticide throughout the plant, protecting it entirely from pests. But the substance also spreads through the pollen and nectar, where it can be absorbed by unfortunate pollinators — particularly, bees.

Many studies have linked neonics to honey-bee colony collapse disorder (CCD) and a decline in birds due to a reduction in insect populations. Pesticide producers have contested the studies, however, saying that they are inconsistent and unrealistic. The new report found that most of the damage doesn’t necessarily come through the nectar and pollen directly, but rather through secondary soil and water contamination. The pesticides are spreading through the entire ecosystem, where they are causing widespread damage. While there was some variability in the study, the results were conclusive enough to support a total ban on these pesticides.

“There is variability in the conclusions, due to factors such as the bee species, the intended use of the pesticide and the route of exposure,” said Jose Tarazona, head of the European Food Safety Authority’s pesticides unit. “Some low risks have been identified, but overall the risk to the three types of bees we have assessed is confirmed.”

Furthermore, as the neonics spread and seep through the ecosystem, it’s only a matter of time before pests start developing resistance, Christopher Connolly of the University of Dundee School of Medicine in the United Kingdom noted in a statement.

The study only analyzed the impact of three neonicotinoids — clothianidin, imidacloprid, and thiamethoxam — all of which have been banned in the European Union but are still allowed widely used elsewhere in the world, including the US. The European Commission has proposed extending the ban to all pesticides in this class, but such measures haven’t been adopted thus far.

“This is strengthening the scientific basis for the Commission’s proposal to ban outdoor use of the three neonicotinoids,” according to a commission statement.

Neonicotinoid pesticides found in 75 percent of honey worldwide

An analysis of honey samples from locations all around the world showed that 75% of them were contaminated with pesticides known to harm bees. About half of the samples actually contained a cocktail of potentially harmful chemicals, besides the neonicotinoid pesticides.

Credit: Pixabay.

Previously, this class of pesticides has been identified by scientists as the most likely cause of colony collapse disorder (CCD) — a strange phenomenon where adult worker honeybees simply disappear from the hives, almost simultaneously, leaving behind the queen and immature bees which could no longer care for themselves. As the name implies, the colony simply collapses.

Honeybees are exposed to this pesticide because its residue is found in nectar and pollen. In fact, it persists in the soil and in woody plants for up to six years after application. While a strong direct link between colony collapse disorder and neonicotinoids has not yet been established, it is increasingly clear that after exposure to these pesticides, honeybees become more susceptible to parasites and pathogens. One study also found that neonicotinoids could prevent the bumblebee queen from laying eggs. Between 2008 and 2013, wild bee diversity in the US dropped by 23 percent, and a previously common bumblebee species was recently listed as endangered.

And it’s not just honeybee populations that are collapsing. Monarch butterflies have been declining significantly, reaching the lowest count ever recorded during the 2013-14 as a result of habitat loss, particularly the loss of milkweed (the species’ only food source), and mortality caused by the use of pesticides. West North America lost 95% of its Monarch butterflies over the last 35 years, according to a distressing recent report.

The long arm of pesticides

Since the first episodes were identified in 2006, CCD has turned into an environmental crisis. Today, most bee species are in decline, with annual regional losses as high as 60%. Bees are some of the world’s most important pollinators, being responsible for about one-third of the plant we eat — a service worth hundreds of billions in the worldwide economy.

The ecological contribution of bees is of course invaluable. Countless species of plants and the animals that feed upon these plants depend on bee pollination for their survival. Where bees disappear, ecosystems are impacted in a cascading effect which is difficult to predict. One thing’s for sure: things aren’t good, and they’re not likely to get better, new research shows.

A new study published in the journal Science joins a body of evidence that suggests pesticides are dramatically interfering with bee foraging and pollination. The international team of researchers analyzed honey samples from nearly 200 hives spread throughout the world. The samples were collected and donated by citizen scientists as part of a project launched by the Botanical Garden of Neuchâtel, Switzerland, in 2016.

“Finding neonicotinoids in honey is perhaps not surprising,” says lead author Christopher Connolly of the University of Dundee, UK. After all, the pesticides are widely used. “But to find neuroactive levels, in so many samples at many global sites, is shocking.”

About 75% of all samples contained measurable quantities of pesticides, which was surprising given that the coverage also included highly remote locations like oceanic islands. About half of the samples contained a mix of various insecticides.

The concentrations of pesticides involved are very low but these chemicals are extremely toxic, up to 10,000 times more potent than DDT, one of the first pesticides of widespread use. DDT was banned for agricultural uses worldwide by the 2001 Stockholm Convention on Persistent Organic Pollutants. 

The highest contamination rates were reported in North America with 86% of samples containing one or more neonicotinoid pesticides. Asia, Europe, and South America followed, with  80%, 79%, and 57% of samples containing pesticides, respectively. The EU introduced a partial ban on neonicotinoids back in 2013, but the European honey samples included in the analysis was sourced before the legislative measure was installed.

“If you look at the minimum concentration for which a significant negative impact on bees has been found, then 48% of our samples exceed this level,” said Professor Edward Mitchell at the University of Neuchâtel.

Neonicotinoids were introduced the mid-1990s. The group consists of various pesticides that are based on the chemical structure of nicotine, and attack the nervous systems of insect pests. But bees, wasps, butterflies, and other insect pollinators seem to have been caught in the cross-fire.

According to a 2014 review, neonicotinoids might seriously jeopardize worldwide food security with far-reaching consequences. Three types of pesticides in this class have been banned in the EU for flowering plants, and the appropriate EU commission is now working on a draft that will ban neonicotinoids from all plants. Other countries will surely follow, hopefully with a worldwide ban similar to DDT — for everyone’s sake.

bee pollinator

Pesticides linked to massive bee die off, largest study of its kind confirms

bee pollinator

Credit: Pixabay

Multiple investigations have linked a class of widely used pesticides called neonicotinoids with colony collapse disorder (CCD). Due to CCD, there are now only half as many honey-producing hives in the United States than there were in 1980. The situation for wild bees, which are the most important pollinators, thus vital elements of the ecosystem and the global food supply, is very similar. Now, the largest study of its kind analyzed bee populations over the last 18 years in the United Kingdom and found indeed that the neonicotinoids are wrecking havoc.

The time span involved in analyzing the data is really important here because it allowed Ben Woodcock, an ecological entomologist at the Centre for Ecology and Hydrology in the U.K., to study the impact of neonicotinoids before these were introduced in the country in 2002. Another clever thing Woodcock and his colleagues did was to study wild bees that forage on pesticide treated rapeseed crops — a crop used to make canola oil which turns the countryside into a sea of yellow once they bloom. What makes rapeseed ideal for this sort of study is that some species enjoy foraging the plants, while others — among the 250 wild bee species in the UK and the 2,500 in the US — stay away.

So, the way the researchers designed their study provided both a baseline (measurements pre-2002), as well as a control to see the kind of influence these pesticides have on colony collapse disorder– a peculiar phenomenon that occurs when most bees leave the hive never to return, leaving behind the queen and some nursing bees.

All of this data, including plots of land known to harbor certain wild bee species, was incorporated into a model. This model didn’t allow the researchers to tell if the number of individual bees on a plot of land increased or decreased, but rather which species vanished or not. This might sound crude, but for the purpose of studying CCD, which can be as unforgiving as the capital punishment, this ought to be enough.

“The negative effects that have been reported previously do scale up to long-term, large-scale multi-species impacts that are harmful,” said Dr Nick Isaac, a co-author of the new paper told BBC.

“Neonicotinoids are harmful, we can be very confident about that and our mean correlation is three times more negative for foragers than for non-foragers.”

Ultimately, the researchers found mini-extinction events were three times more common in bees that foraged on the pesticide-laced rape crops than in those that didn’t. Like other studies that preceded the paper published in Nature Communications, it’s impossible to say for sure that the neonicotinoids are responsible for CCD, but the link is there and it’s pretty strong. And unlike previous studies, the current one looked at data from the field, not collected in labs.

Bayer Crop Science, a major manufacturer of neonicotinoid pesticides, was quick to take note of the study and issued a statement for the Washington Post saying:

“The authors chose to investigate only one potential factor, namely neonicotinoid insecticides,” the statement said. “This was chosen out of many different factors which may have an influence on the development of wild bees, for example landscape structures, climatic conditions, availability of specific foraging plants and nesting habitats. It is a well-known fact that the structure of agricultural landscapes in large parts of Europe has changed substantially in the last decades. The area of landscape structures available for nesting or foraging, especially for specialized species, has significantly declined, resulting in fewer habitats for pollinators.”

While Bayer seems to allude to science-based facts like the that indeed climate change and habitat destruction also contribute to CCD, the fact that the company doesn’t acknowledge how its business is affecting bees around the world is disheartening.

Since 2013, the European Union has banned the use of neonicotinoids, though some pesticides belonging to the class are still in use in the United Kingdom. The restrictions on chemicals like thiamethoxam, clothianidin and imidacloprid could be rolled back in early 2017 if a review currently in the works by the European Food Safety Authority (Efsa) decides so. Mounting scientific evidence as well as two million petitioners initially led to the restrictions all around the EU, but the pesticide industry has heavily lobbied since, arguing that the ban costs farmers hundreds of millions and is unnecessary for bees. In the United States, there are currently no restrictions for neonicotinoids, despite the EPA has acknowledged the risks these pose to pollinators.



Neonicotinoid chemicals and bees

Pesticides threaten bees, birds and worms alike

A new study has shown that neurotoxic pesticides blamed for the huge drop in bee numbers are also equally affecting butterflies, worms, fish and birds.

Killing the Bees

Neonicotinoid chemicals and bees

Poor fellows! The decline of bees around the world is increasingly linked with neonicotinoid chemicals.

Analyzing two decades of research on the topic, they found out that two classes of pesticides – neonicotinoids and fipronil – show “clear evidence of harm”.

“We are witnessing a threat to the productivity of our natural and farmed environment,” said Jean-Marc Bonmatin of France’s National Centre for Scientific Research, co-author of the report entitled the Worldwide Integrated Assessment.

These nerve-targeting poisons are supposed to be protecting food security – but that’s really the opposite of what they’re doing in the long run. Bees are responsible for pollinating a huge amount of the global food, and these pesticides are “imperilling the pollinators, habitat engineers and natural pest controllers at the heart of a functioning ecosystem.”

In case you’re not aware, bee populations are dwindling. All around the world, bee populations are dropping more and more, and until recently, scientists still wasn’t sure why this was happening. Now, even though there isn’t a general consensus, there are very strong indications that it’s pesticides that trigger this drastic reduction in bee numbers. To make things even clearer, in countries which have banned these pesticides, bee numbers are starting to rise again.

More threats

But as huge as the bee damage is, other creatures are threatened just as much by the insecticides. As they seep into the underground or waters, neonics affect freshwater snails and water fleas, then birds, and finally fish, amphibians and certain microbes. They have also been linked with autism.

However, the most damage is done to terrestrial invertebrates such as earthworms. We don’t really think about earthworms, because, well, they’re not pretty, and most people don’t see them as useful – but that’s a shallow point of view. Earthworms are crucial in ecosystems, as they provide crucial soil-enrichment and aeration. With dropping worm populations, the local plants will be under even more stress, and the results will be devastating.

“The combination of their widescale use and inherent properties, has resulted in widespread contamination of agricultural soils, freshwater resources, wetlands, non-target vegetation, estuarine and coastal marine systems,” the authors wrote.