Imidacloprid effects on bee population
Encyclopedia
Imidacloprid
is a systemic neonicotinoid insecticide
produced by the German chemical firm Bayer CropScience and sold under such trade names as Gaucho, Admire, Merit, Advantage, Confidor, Provado, and Winner. It acts as a neurotoxin and interferes with the transmission of nerve impulses in insects by binding to specific nicotinic acetylcholine receptors. Imidacloprid is implicated in honeybee colony collapse disorder
.
As a systemic pesticide, imidacloprid translocates or moves readily from the soil into the leaves, flowers, fruiting bodies, pollen, nectar, and guttation fluid of plants. Imidacloprid is also mobile and persistent in the environment and has the potential to accumulate in soil. Some of its degradates are as toxic and in some cases more toxic to bees than the parent compound.
In 2008 in southern Germany, beekeepers reportedly lost two-thirds of their bees from clothianidin-treated seeds. As a result of this incident, the German Office of Consumer Protection and Food Safety suspended the use of imidacloprid and clothianidin, but later reinstated some of the uses of these chemicals. Following the German incident, Italy and Slovenia suspended certain uses of imidacloprid, clothianidin, thiamethoxam, and fipronil based on concerns for bees
Environmental groups in Europe and the United States are now demanding a ban on the neonicotinoids until the governments can show that these chemicals are safe for pollinators. Despite the large number of laboratory and field studies produced by the registrant of imidacloprid, there is not sufficient valid data to indicate if this pesticide is safe on a long-term basis for bee colonies. A number of environmental groups have presented petitions to ban these pesticides to the regulatory agencies in the United Kingdom and the United States, but thus far the governments in these countries have not been receptive to removing any of the uses of these pesticides from the market.
Dozens of research articles have been published in peer-reviewed journals, which show sublethal effects to adult bees exposed to low levels of imidacloprid. In these studies, sub-lethal doses of 1-24 ug/kg and 0.1 - 20 ng/bee have been shown to impair navigation, foraging behavior, feeding behavior, and olfactory learning performance in honeybees (Apis mellifera). Other studies examining higher levels of imidacloprid (50 - 500 ppb) also found that imidacloprid decreases foraging activity and affects bee mobility and communication capacity.
Many tunnel and field studies have been conducted to show the potential effects of imidacloprid in the natural environment. Unfortunately, most of these field studies have design and implementation deficiencies, which make them difficult to use.
, an important enzyme that allows the bees to sterilize their colony and brood food. Without this enzyme, bees can become more susceptible to infections by pathogens. Both the USDA study and the INRA study demonstrate that a combination of stressors (pesticides and pathogens) may be responsible for the recent high level of bee losses.
Gerard Eyries, marketing manager for Bayer's agricultural division in France, states that studies confirm that imidacloprid leaves a small residue in nectar and pollen
, but there is no evidence of a link with the drop in France's bee population, adding, "It is impossible to have zero residue. What is important is to know whether the very tiny quantities which have been found have a negative effect on bees." He also added that the product was sold in 70 countries with no reported side effects.
Other independent studies have indicated that imidacloprid residues in plants can be higher:
Some also pointed out that bee colony losses could also be due to the use of imidacloprid on other crops such as corn, or from the replacement of imidacloprid by another systemic insecticide called fipronil
. Fipronil is as toxic to honeybees on an acute oral basis as imidacloprid. Indeed in May 2003, the DGAL (Direction Générale de l'Alimentation du ministère de l'Agriculture ) indicated death of bees observed in the south of the country had been caused by acute toxicity by fipronil (trade name Regent
). Imidacloprid was not believed to be the likely cause for the bees death.
seed treatment products used in oilseed rape and sweetcorn
, a few weeks after honeybee keepers in the southern state of Baden Württemberg reported a wave of honeybee deaths linked to one of the pesticides, clothianidin
.
In August 2008, the Coalition against Bayer Dangers (CBG) brought a legal case against Werner Wenning, Bayer's chairman, for marketing dangerous pesticides (neonicotinoids), which are causing the death of bees worldwide.
, a neonicotinoid similar to imidacloprid. The EPA document states:
"This compound is toxic to honey bees. The persistence of residues and potential residual toxicity
of clothianidin in nectar and pollen suggests the possibility of chronic toxic risk to honey bee
larvae and the eventual instability of the hive."
to push the United States
and European Union
to join the ban of the neonicotinoid pesticide
s.
, was released in theatres in the UK. The film interviewed a number of experts in connection with CCD
and suggested a link does exist between neonicotinoid pesticides and CCD. However, the experts interviewed conceded no firm scientific data yet exist. Industry-sponsored studies appear to be inconsistent with those produced by independent scientists.
In February 2010, the documentary film Nicotine Bees was released. This film analyzes the possible factors contributing to the large bee die-offs worldwide and concludes that the large use of neonicotinoids is the most probable cause of the recent bee die-offs.
Imidacloprid
Imidacloprid is a nicotine-based, systemic insecticide, which acts as a neurotoxin and belongs to a class of chemicals called the neonicotinoids. Although it is now off patent, the primary manufacturer of this chemical is Bayer CropScience,...
is a systemic neonicotinoid insecticide
Insecticide
An insecticide is a pesticide used against insects. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind...
produced by the German chemical firm Bayer CropScience and sold under such trade names as Gaucho, Admire, Merit, Advantage, Confidor, Provado, and Winner. It acts as a neurotoxin and interferes with the transmission of nerve impulses in insects by binding to specific nicotinic acetylcholine receptors. Imidacloprid is implicated in honeybee colony collapse disorder
Colony Collapse Disorder
Colony collapse disorder is a phenomenon in which worker bees from a beehive or European honey bee colony abruptly disappear. While such disappearances have occurred throughout the history of apiculture, the term colony collapse disorder was first applied to a drastic rise in the number of...
.
As a systemic pesticide, imidacloprid translocates or moves readily from the soil into the leaves, flowers, fruiting bodies, pollen, nectar, and guttation fluid of plants. Imidacloprid is also mobile and persistent in the environment and has the potential to accumulate in soil. Some of its degradates are as toxic and in some cases more toxic to bees than the parent compound.
History
Imidacloprid was first registered in the United Kingdom in 1993 and in the United States and France in 1994. In the mid to late 1990s, French beekeepers began to experience massive die-offs of bees in and near fields where imidacloprid (Gaucho) was being used. In 1999 after French beekeepers protested in the streets of Paris, the French Minister of Agriculture suspended the use of imidacloprid on sunflower seeds. The French Agriculture Minister also appointed a team of expert scientists to examine the impact of imidacloprid on bees. In 2003, this team of experts called the Comite Scientific et Technique issued a 108-page report, which concluded that imidacloprid poses a significant risk to bees. In 2004, the French Minister of Agriculture suspended the use of imidacloprid as a seed treatment for maize (corn). A monitoring study conducted by Chauzat et al.(2006) in France found that imidacloprid was the most commonly detected insecticide in beehives and was found in 49% of the 81 samples.In 2008 in southern Germany, beekeepers reportedly lost two-thirds of their bees from clothianidin-treated seeds. As a result of this incident, the German Office of Consumer Protection and Food Safety suspended the use of imidacloprid and clothianidin, but later reinstated some of the uses of these chemicals. Following the German incident, Italy and Slovenia suspended certain uses of imidacloprid, clothianidin, thiamethoxam, and fipronil based on concerns for bees
Environmental groups in Europe and the United States are now demanding a ban on the neonicotinoids until the governments can show that these chemicals are safe for pollinators. Despite the large number of laboratory and field studies produced by the registrant of imidacloprid, there is not sufficient valid data to indicate if this pesticide is safe on a long-term basis for bee colonies. A number of environmental groups have presented petitions to ban these pesticides to the regulatory agencies in the United Kingdom and the United States, but thus far the governments in these countries have not been receptive to removing any of the uses of these pesticides from the market.
Acute
Compared to other commonly used pesticides, imidacloprid is one of the most toxic insecticides to bees. On an acute basis, the lethal dose to kill 50% of the population of adult honeybees (LD50) equals 0.078 micrograms active ingredient/bee (ug a.i./bee) for contact toxicity and 0.0038 ug a.i./bee for oral ingestion. Other insecticides that are as toxic or more toxic than imidacloprid include spinosad, emamectin benzoate, clothianidin, fipronil, thiamethoxam, and dinotefuran.Sublethal
The majority of studies that measure toxicity of pesticides to bees focus on estimating the lethal dose (LD50) in acute toxicity tests to adult honeybees. This is only a partial measure of the harmful effects that pesticides can have on bees. For a complete analysis of the impact of pesticides to bees, sublethal effects should be considered.Dozens of research articles have been published in peer-reviewed journals, which show sublethal effects to adult bees exposed to low levels of imidacloprid. In these studies, sub-lethal doses of 1-24 ug/kg and 0.1 - 20 ng/bee have been shown to impair navigation, foraging behavior, feeding behavior, and olfactory learning performance in honeybees (Apis mellifera). Other studies examining higher levels of imidacloprid (50 - 500 ppb) also found that imidacloprid decreases foraging activity and affects bee mobility and communication capacity.
Chronic
In 10-day chronic feeding studies with honeybees (Apis mellifera), 50% mortality was reached at levels between 0.1 and 10 ug/kg imidacloprid. Other chronic toxicity studies conducted by Moncharmont et al. (2003) and Decourtye et al. (1999) have demonstrated chronic NOAEC values of <4 ppb and 4 ppb, respectively in honeybees. In bumble bees, Mommaerts et al. (2009) demonstrated a LOAEC of 10 ppb for imidacloprid.Many tunnel and field studies have been conducted to show the potential effects of imidacloprid in the natural environment. Unfortunately, most of these field studies have design and implementation deficiencies, which make them difficult to use.
Synergistic effects
Two research teams led by Jeff Pettis at the U.S. Department of Agriculture and Cedric Alaux at INRA/France have demonstrated that interactions between the pathogen Nosema and a neonicotinoid imidacloprid significantly weaken the immune systems of honeybees (Apis mellifera). In their research, Alaux et al. (2010) found that bees infected with Nosema and exposed to 0.7 ug/kg imidacloprid had an increased rate of mortality compared to the controls. The combination of Nosema and imidacloprid also significantly decreased the activity of glucose oxidaseGlucose oxidase
The glucose oxidase enzyme is an oxido-reductase that catalyses the oxidation of glucose to hydrogen peroxide and D-glucono-δ-lactone. In cells, it aids in breaking the sugar down into its metabolites....
, an important enzyme that allows the bees to sterilize their colony and brood food. Without this enzyme, bees can become more susceptible to infections by pathogens. Both the USDA study and the INRA study demonstrate that a combination of stressors (pesticides and pathogens) may be responsible for the recent high level of bee losses.
Other studies
Bayer CropScience studies show that the maximum dose of imidacloprid for which no adverse effects were observed in bees is 20 ppb. Since Bayer claims that residue levels are usually below 5 ppb in pollen and nectar, they contend that imidacloprid poses a negligible risk to bees.Gerard Eyries, marketing manager for Bayer's agricultural division in France, states that studies confirm that imidacloprid leaves a small residue in nectar and pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
, but there is no evidence of a link with the drop in France's bee population, adding, "It is impossible to have zero residue. What is important is to know whether the very tiny quantities which have been found have a negative effect on bees." He also added that the product was sold in 70 countries with no reported side effects.
Other independent studies have indicated that imidacloprid residues in plants can be higher:
- 10 to 20 ppb in upper leaves
- 100 to 200 ppb in other leaves
- 1.5 ppb in nectar
- 2 to > 13 ppb in pollen
Uncertainties
It is important to note that the majority of studies conducted on pollinators have been performed in adult honeybees (Apis mellifera). Very few studies have been conducted on wild bees, most of which are solitary and raise their young in burrows and small colonies. There are also few studies that have been conducted on brood, larvae, or the queen, making it difficult to determine the impact of pesticides on different members of the colony and life stages of the bee.2001
In 2001, Bayer CropScience brought a judicial case against Maurice Mary, one of the leaders of the French Association of Beekeepers for disparagement of the chemical imidacloprid. The action was dismissed by the court in May 2003.2002
A similar battle occurred in Nova Scotia, where beekeepers believed that imidacloprid used on potatoes resulted in massive losses of bees, which are needed for blueberry pollination.2003
In 2003, French Agricultural Minister Jean Glavany again extended the suspension of the use of imidacloprid on sunflower seeds. In spite of a four-year ban already on sunflower seeds treatment, a significant drop in bee individuals was not observed. Beekeepers were cited as saying the measure was insufficient since studies found that imidacloprid accumulates in soil and leaves a residue. Even after two years, plants sowed on the same spot as the crop could contain traces of the product.Some also pointed out that bee colony losses could also be due to the use of imidacloprid on other crops such as corn, or from the replacement of imidacloprid by another systemic insecticide called fipronil
Fipronil
Fipronil is a broad spectrum insecticide that disrupts the insect central nervous system by blocking the passage of chloride ions through the GABA receptor and glutamate-gated chloride channels, components of the central nervous system. This causes hyperexcitation of contaminated insects' nerves...
. Fipronil is as toxic to honeybees on an acute oral basis as imidacloprid. Indeed in May 2003, the DGAL (Direction Générale de l'Alimentation du ministère de l'Agriculture ) indicated death of bees observed in the south of the country had been caused by acute toxicity by fipronil (trade name Regent
Regent
A regent, from the Latin regens "one who reigns", is a person selected to act as head of state because the ruler is a minor, not present, or debilitated. Currently there are only two ruling Regencies in the world, sovereign Liechtenstein and the Malaysian constitutive state of Terengganu...
). Imidacloprid was not believed to be the likely cause for the bees death.
2008
In June 2008, the German Federal Office of Consumer Protection and Food Safety suspended the registration of eight neonicotinoid pesticideNeonicotinoids
Neonicotinoids are a class of insecticides which act on the central nervous system of insects with lower toxicity to mammals. Neonicotinoids are among the most widely used insecticides worldwide, but recently the uses of some members of this class have been restricted in some countries due to a...
seed treatment products used in oilseed rape and sweetcorn
Sweetcorn
Sweet corn is a variety of maize with a high sugar content. Sweet corn is the result of a naturally occurring recessive mutation in the genes which control conversion of sugar to starch inside the endosperm of the corn kernel...
, a few weeks after honeybee keepers in the southern state of Baden Württemberg reported a wave of honeybee deaths linked to one of the pesticides, clothianidin
Clothianidin
Clothianidin is an insecticide developed by Takeda Chemical Industries and Bayer AG. Similar to thiamethoxam and imidacloprid, it is a neonicotinoid. Neonicotinoids are a class of insecticides which act on the central nervous system of insects with lower toxicity to mammals...
.
In August 2008, the Coalition against Bayer Dangers (CBG) brought a legal case against Werner Wenning, Bayer's chairman, for marketing dangerous pesticides (neonicotinoids), which are causing the death of bees worldwide.
2010
In November 2010, an EPA document was released, detailing the risks to honeybees from exposure to clothianidinClothianidin
Clothianidin is an insecticide developed by Takeda Chemical Industries and Bayer AG. Similar to thiamethoxam and imidacloprid, it is a neonicotinoid. Neonicotinoids are a class of insecticides which act on the central nervous system of insects with lower toxicity to mammals...
, a neonicotinoid similar to imidacloprid. The EPA document states:
"This compound is toxic to honey bees. The persistence of residues and potential residual toxicity
of clothianidin in nectar and pollen suggests the possibility of chronic toxic risk to honey bee
larvae and the eventual instability of the hive."
2011
In January 2011, an online petition to save the bees was launched by Avaaz.orgAvaaz.org
Avaaz.org is a global civic organization launched in January 2007 that promotes activism on issues such as climate change, human rights, corruption, poverty, and conflict...
to push the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
to join the ban of the neonicotinoid pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
s.
Media portrayal
In October 2009, a documentary film, Vanishing of the BeesVanishing of the Bees
Vanishing of the Bees is a 2009 documentary film by Hive Mentality Films & Hipfuel films, directed by George Langworthy and Maryam Henein and released in the United Kingdom on October 9. The story centers around the sudden disappearance of honey bees from beehives around the world, caused by the...
, was released in theatres in the UK. The film interviewed a number of experts in connection with CCD
Colony Collapse Disorder
Colony collapse disorder is a phenomenon in which worker bees from a beehive or European honey bee colony abruptly disappear. While such disappearances have occurred throughout the history of apiculture, the term colony collapse disorder was first applied to a drastic rise in the number of...
and suggested a link does exist between neonicotinoid pesticides and CCD. However, the experts interviewed conceded no firm scientific data yet exist. Industry-sponsored studies appear to be inconsistent with those produced by independent scientists.
In February 2010, the documentary film Nicotine Bees was released. This film analyzes the possible factors contributing to the large bee die-offs worldwide and concludes that the large use of neonicotinoids is the most probable cause of the recent bee die-offs.
See also
- Pesticide toxicity to beesPesticide toxicity to beesPesticides vary in their effects on bees. Contact pesticides are usually sprayed on plants and can kill bees when they crawl over sprayed surfaces of plants or other media...
- Bees and toxic chemicalsBees and toxic chemicalsBees can suffer serious effects from toxic chemicals in their environments. These include various synthetic chemicals, such as insecticides and fertilizers, as well as a variety of naturally occurring chemicals from plants, such as ethanol resulting from the fermentation of organic material...
- Colony collapse disorderColony Collapse DisorderColony collapse disorder is a phenomenon in which worker bees from a beehive or European honey bee colony abruptly disappear. While such disappearances have occurred throughout the history of apiculture, the term colony collapse disorder was first applied to a drastic rise in the number of...
- Vanishing of the BeesVanishing of the BeesVanishing of the Bees is a 2009 documentary film by Hive Mentality Films & Hipfuel films, directed by George Langworthy and Maryam Henein and released in the United Kingdom on October 9. The story centers around the sudden disappearance of honey bees from beehives around the world, caused by the...
External links
- webpage from Bayer CropScience page on Imidacloprid and Bee safety noting independent trials show product as safe for bees
- link to example of Bayer product containing Imidiacloprid noting product is a high risk to bees
- juridical case lost by Bayer, requalified defaming toward Maurice Mary
- demonstration against Imidacloprid and links on beekeeping.com
- imidacloprid and "mad bee disease"
- Honey bees in US facing extinction, The TelegraphThe Daily TelegraphThe Daily Telegraph is a daily morning broadsheet newspaper distributed throughout the United Kingdom and internationally. The newspaper was founded by Arthur B...
, 14 March 2007 - Various links on scientific reports and news articles (French & English) on the website of the Union Nationale de l'Apiculture Française (UNAF) union
- British Bee Keepers Association position on Bayer's pesticides
- Official documentary website of the 2009 documentary film Vanishing of the Bees
- Bayer-kills-bees.com advocacy site updated about five times per month
- How to Reduce Bee Poisoning from Pesticides PNW 591, (Pacific Northwest Extension)