Nicotine-based pesticides, bees, and the deniers

Nicotine, as we all know by now, is a powerful poison.

blog-black-leafSo powerful that on 22 November 1963 [yes, that day] the Central Intelligence Agency once sent an agent to kill Fidel Castro with a syringe disguised as a fountain pen and filled  Black Leaf 40, a powerful nicotine-based insecticide that our father used the stuff to kill mites on his roses.

Black Leaf 40 is no longer with us, following a 1992 ban on its use by the Environmental Protection Agency — you know, the department Trump wanted to eliminate — because of its widespread long-term environmental hazards as well as it’s propensity to poison people.

But the ban on Black Leaf 40 didn’t stop the widespread current use of nicotine-based insecticides, using nicotine-based chemicals called neonicotinoids.

How widespread is their use here in the U.S.?

Consider this chart from How Neonicotinoids Can Kill Bees — The Science Behind the Role These Insecticides Play in Harming Bees, a very informative new report from the Xerces Society for Invertebrate Conservation:

Estimated Annual Agricultural Use of Neonicotinoids in the United States: 1994–2014

Estimated Annual Agricultural Use of Neonicotinoids in the United States: 1994–2014

More from the report’s Executive Summary:

Neonicotinoids have been adopted for use on an extensive variety of farm crops as well as ornamental landscape plants. They are the most widely used group of insecticides in the world, and have been for a decade. Developed as alternatives for organophosphate and carbamate insecticides, neonicotinoids are compounds that affect the nervous system of insects, humans, and other animals. Although less acutely toxic to mammals and other vertebrates than older insecticides, neonicotinoids are highly toxic in small quantities to many invertebrates, including beneficial insects such as bees.

The impact of this class of insecticides on pollinating insects such as honey bees and native bees is a cause for concern. Because they are systemic chemicals absorbed into the plant, neonicotinoids can be present in pollen and nectar, making them toxic to pollinators that feed on them. The potentially long-lasting presence of neonicotinoids in plants, although useful from a pest management standpoint, makes it possible for these chemicals to harm pollinators even when the initial application is made weeks before the bloom period. In addition, depending on the compound, rate, and method of application, neonicotinoids can persist in the soil and be continually taken in by plants for a very long periods of time.

Across Europe and North America, a possible link to honey bee die-offs has made neonicotinoids controversial. In December 2013, the European Union significantly limited the use of clothianidin, imiadcloprid, and thiamethoxam on bee-attractive crops. In the United States, Canada, and elsewhere, local, state, and federal decision makers are also taking steps to protect pollinators from neonicotinoids. For example, the U.S. Fish and Wildlife Service phased out all uses of neonicotinoids on National Wildlife Refuges lands starting in January 2016.

The European Union has banned the used of three neonicotinoids —  clothianidin, thiamethoxam and imidacloprid — and restricted the use of a fourth, fipronil.

Given that bees are responsible for pollinating much of the food we eat, impacts on apians is a cause for deep concern.

A Colorado city bans nicotine-derivative insecticides

More on the good reasons for concern, as summarized in the following, taken from  Boulder, Colorado city government website section on protecting pollinators:

One group of pesticides, the neonicotinoid insecticides (also called neonics), stand out as a major contributing factor to the catastrophic loss of bees and other animals. Neonicotinoid insecticides are extremely toxic to pollinators at very low doses. They are absorbed and taken up by the plant, ending up in all plant tissues, including the nectar and pollen collected by pollinators and the seeds, fruits, and leaves eaten by other animals. These products are often applied as soil treatments in the form of granules or drenches, where they can persist for many years and continue to contaminate plants, kill earthworms and other important beneficial soil organisms, and run off into surface water where they can kill aquatic invertebrates. An  analysis by a consortium of independent scientists from around the globe reviewed more than 800 peer-reviewed studies and concluded that neonicotinoid insecticides pose a significant risk to the world’s pollinators, worms, birds and other animals and that immediate action is needed. Studies conclude that pesticide application rates that regulatory agencies consider protective to the environment actually harm aquatic organisms found in surface waters (dragonflies mayflies, snails and other animals that form the base of the food chain and a healthy, clean watershed) and build up in soils to levels that can kill soil organisms.

The city was so concerned that in May 2015, the city banned use of the chemicals on city land and urged similar actions by individuals, corporations, and state and federal government as well.

Canada to ban a popular neonicotnoid

One of the most widely used neonicitinoids in imidacloprid, and back in November CBC News reported that the Canadian government’s health agency is proposing a nationwide band on the substance based on its impacts on bees:

“Based on currently available information, the continued high-volume use of imidacloprid in agricultural areas is not sustainable,” the assessment states.

It proposes phasing out all agricultural uses of imidacloprid, and a majority of other uses, over the next three to five years.

“I’m really surprised,” said Mark Winston, a professor of apiculture at Simon Fraser University and senior fellow at the university’s Centre for Dialogue.

“To take an action to phase out a chemical that is so ubiquitous, and for which there is so much lobbying pressure from industry, I think that’s a really bold move.”

After the jump, impacts from use on one crop, the industry denial machine, and bee behavioral impacts. . .

A study looks at impacts from use on one crop

A team of British scientists headed Ben A. Woodcock and Nicholas J. B. Isaac of the government’s Natural Environment Research Council’s Centre for Ecology and Hydrology in Wallingford examined what happens to bee populations on one staple crop, in this case fields of oilseed rape [canola is one variety] in Old Blighty.

They found than even less-than-lethal doses can lead to colony collapse and local extinction.

From their report, published [open access] 16 August 2016 in Nature:

This study provides the first evidence for community level national scale impacts on the persistence of wild bee populations resulting from exposure to neonicotinoid treated oilseed rape crops. While correlational, the identification of reduced persistence rates suggest that sublethal impacts reported by previous studies do ‘scale up’ to cause population extinctions over long time scales. Wild bee species that forage on oilseed rape were three times as negatively affected by exposure to neonicotinoids than non-foragers. This supports the hypothesis that the application of this pesticide to oilseed rape is a principle mechanism of exposure for wild bee communities. Although not tested in the existing study this finding also suggests that other mass flowering crops (for example, sunflower) could similarly provide a route of exposure to neonicotinoids that could lead to the loss of population persistence for wild bees.

More on the report from Reuters:

Wild bees that forage from oilseed rape crops treated with insecticides known as neonicotinoids are more likely to undergo long-term population declines than bees that forage from other sources, according to the findings of an 18-year study.

The new research covered 62 species of bee found in the wild in Britain and found a link between their shrinking populations and the use of neonicotinoid pesticides.


Neonicotinoids were initially licensed for use as a pesticide in Britain in 2002. By 2011, the proportion of UK oilseed rape seeds treated with them was 83 percent, according to the researchers leading this latest study.

Going back to data from 1994 up to 2011, the scientists analyzed how large-scale applications of neonicotinoids to oilseed rape crops influenced bee population changes.

But some remain in denial, profitably so

Needless to say, the corporations making fortunes out of peddling these lethal drugs [a pesticide is simply drug intended for use only at lethal doses], deny any harm except for the targeted kills.

From the website of the Competitive Enterprise Institute, an industry-funded neolibertarian NGO that also lobbies against climate change legislation:

There is no consistent correlation between neonicotinoids and hive losses. If neonicotinoids were a cause of significant hive losses, we would expect to see at least some correlation between their use and high hive losses, but no such pattern has been observed since their introduction in the 1990s. In many places where these chemicals are used widely, such as in Australia, CCD is not a problem. And in Europe during 2013-2014, hives survived well in many areas where neonicotinoids were used.

Field studies find no health effects from “sublethal exposures” to neonicotinoids. To date, there are no studies showing that honeybees have suffered ill effects from “field-relevant” neonicotinoid exposures. Only studies that feed the bees unrealistically high levels of the chemicals show adverse effects. Studies of bees in the field where neonicotinoids are used show no measureable effects.

Neonicotinoids do not present the most significant pesticide exposure to honeybees. While activists like to blame neonicotinoids for the disappearance of hibernating bees, little of these chemicals is actually found in the hives. Instead, most of the chemicals found in the hive are put there by beekeepers trying to fight various diseases carried by mites and other organisms. “It’s like chemotherapy. They know it’s bad, but it’s a lot better than the alternative,” says bee researcher Dennis vanEngelsdorp.

And that brings us to the latest study

Not only can neonicotinoids kill bees.

They can also change their behavior.

From the Society for Integrative and Comparative Biology via Newswise:

In a plastic, lasercut box blacked out with paint and lit with red light, worker bumblebees (Bombus impatiens) go about their daily activities: interacting with fellow adults, extracting food from honey pots, feeding larvae, and occasionally venturing out to forage for nectar. While this nest is far from normal, the bees that live here have adapted to their new space remarkably well. Still, all is not well within the nest, and not because of its strange form. Some bees have abandoned their daily patterns and are spending more time alone, on the periphery. Others are spending less time caring for the utterly dependent larvae that will become the next generation of bumblebees.

Within the nest, the chaotic center of bumblebee life, social behavior and interactions are crucial for bee population health and the production of young. When social behavior and the care of young changes, population numbers become more susceptible to decline. James Crall, a postdoc with the Planetary Health Alliance at Harvard University, graduate student Callin Switzer and colleagues have linked these changes in social behavior with sublethal exposure to the neonicotinoid pesticide, imidacloprid.

For their study, Crall developed an ‘automated behavioral tracking system’ that allows a computer connected to cameras within the nest to recognize individual bees and create data points that indicate position and proximity to others. “Bumblebee nests are not the organized, beautiful geometry of the honeybee,” said Crall. Instead, “they’re more a hodge-podge of food and larvae in a pile in the middle of the nest space.” This automated tracking system allowed Crall to see into “messy, complex, realistic, individual scenes” and could be adapted for use in natural environments.

While it might seem like the hardest part of this experiment would be development of a tracking system, Crall said the process of tagging each bee was both an art and a science, a “race against time” to glue on tags before the bees woke up, and “by far the hardest and slowest part of the experiment”. Tagging a colony of bees could consume entire days, while bee movement within nests was only recorded for a few hours. After tagging, bees were observed before and after exposure to imidacloprid. Crall then evaluated millions of data points to assess behavioral changes among treated bees. He found that bees exposed to the pesticide reduced the frequency of brood care and tended to gravitate towards the perimeter of the nest, becoming less social.

Outside the nest, this neonicotinoid also has significant effects on pollination and foraging behavior. Callin Switzer, a PhD student at Harvard University, worked to study the effects of imidacloprid on pollination behavior. Specifically, Switzer focused on buzz pollination, the ability of bumblebees to forage on and pollinate certain types of plants, using vibrations. Before exposing bees to imidacloprid, Switzer recorded the sound of bees foraging on tomato blossoms. These same bees were then exposed to the neonicotinoid and allowed to resume foraging. However, bees exposed to imidacloprid, at doses similar to those encountered in a single day, were less likely to resume foraging than unexposed bees.

Imagine it’s summer, and in a field by the side of the road, rows on rows of tomato plants wait to be pollinated and produce their delicious fruit. These plants reproduce more following buzz pollination, a service eastern bumble bees are uniquely equipped to provide. However, these tomato plants are covered in imidacloprid, and when bumblebees forage here, they are exposed to sublethal levels of this pesticide. As the season progresses and exposure to imidacloprid increases, bees are still present, but they begin to forage less, don’t care for their young as often, and social interactions change. Outside the nest, a decrease in foraging by affected bumblebees could contribute to lessened crop production and colony food supplies. Within the nest, altered social networks and a decrease in caring for young could lead to population declines in future generations. As the single most important native pollinator species in North America, continued use of the neonicotinoid imidacloprid could have far-reaching effects on the survival of the Common Eastern Bumblebee and the plants they pollinate.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s