Bees Dying in Colony Collapse from Neonicotinoid Pesticides
Bees are dying from colony collapse across Europe and North America. Research is now finding that the cause is neonicotinoid pesticides.
The honeybee is not just important because it supplies us with medicinal raw honey. The honeybee also pollinates many of the plants that produce our food. Without healthy honeybees, we will likely starve.
The primary causes of the mysterious bee colony collapse disorder has now been established with a combination of scientific and firsthand knowledge from large and small beekeepers from around the world.
For a number of years, the disappearance of uncounted hives among beekeepers throughout the world and particularly in the United States was a complete mystery.
Researchers have estimated that about 35 percent of U.S. honeybees have been killed by the disorder. The disorder has been mystifying researchers looking for a single pathogen or threat because they have found that affected hives have had a variety of infections, from fungi to bacteria to mites – and most recently, fly larvae – with the latest news reports focusing on “zombie bees.”
Europe’s previous collapse
This mirrored a similar collapse of hives throughout Europe a decade ago. This produced beekeeper protests and the research by governmental and private scientists. Eventually, several European Union countries banned systemic pesticides after evidence found them to be the primary cause for the loss of hives throughout Europe.
The problem, according to scientists and bee experts, is that the systemic pesticides damage the immune systems of the bees. This allowed infections previously fought off to invade the hives. This weakened immune system and subsequent abandoning of the hive – the bee experts agree – is most prevalent following the hives being exposed to fields that have been sprayed with systemic pesticides.
U.S. agencies remain unconvinced
Even with robust research, government agencies in the U.S. remain unconvinced, as most of the research utilized by the EPA – the agency governing the marketability of systemic pesticides – has only studied the short-term affects of the pesticides upon the bees, rather than the non-lethal, residual effects of systemic pesticides – which the plants harbor over long periods.
What are systemic pesticides?
Systemic pesticides, which include the category called neonicotinoids, include (in a list provided by The Senior Extension Associate at Penn State University) the common pesticide brand names:
Actara, Platinum, Helix, Cruiser, Adage, Meridian, Centric, Flagship, Poncho, Titan, Clutch, Belay, Arena, Confidor, Merit, Admire, Ledgend, Pravado, Encore, Goucho, Premise, Assail, Intruder, Adjust and Calypso.
Government-sponsored European research found direct evidence that systemic pesticides resulted in a delayed accumulation of weakened immune system and damage to the honeybees’ navigation systems. In one taped excerpt, the film compares a honeybee’s behavior gathering pollen from a systemic-pesticide-free sunflower with one that was previously treated with a neonicotinoid pesticide. The pesticide-free sunflower hosted normal bee pollen-collecting activity, while the systemic-pesticide sunflower caused the bee to become disoriented, and eventually lose the ability to stay attached to the sunflower’s filaments. The result was the bee’s hampered navigation and a weakened honeybee.
Once back to the hive (for those who can make it back), the tainted and weakened bee supplies the poisoned pollen to the hive, damaging the workers and nursing bees, and eventually, the queen.
This assumption that non-lethal doses of low-level, systemic pesticides can damage the bee’s ability to navigate was confirmed in a 2001 study from French university researchers, who found that doses of imidacloprid, a neonicotinoid systemic pesticide, directly affected the bee’s navigation abilities. The researchers concluded that: “The ability of the honeybee to move in an open-field-like apparatus is impaired at the doses of 2.5, 5, 10, and 20 ng/bee. These effects are amplified with time and reach a maximum 60 min after application.”
Bee hives in Europe on the comeback
Recent beehive counts in Europe have revealed that bee hives have made a dramatic comeback since the European Union’s ban on these systemic pesticides,.
The link between damage to wildlife species by pesticides is not a new one. Damage to reptiles and frogs, seals, bats and monarch butterflies have been shown links to pesticide residues in past studies. In the case of honeybees, these are insects being exposed to insecticides.
Issues with modern beekeeping methods that also contribute to the weakening of the immune systems of the bees. These include feeding the bees white sugar while transporting them over long distances, and utilizing laboratory-cloned queen bees instead of letting honeybees birth and develop their own – more versatile – queens. When these laboratory-cloned bees are introduced, they must be quarantined by the beekeeper in a section of the hive in order to prevent the bees from killing the cloned queen.
These pointed out, the film concludes that the systemic pesticides are the most prevalent cause, as multiple large, commercial beekeepers testify that their die-offs occur after their bees are allowed to forage among systemic pesticide-treated crops.
Research proving the pesticide cause
A study by researchers from Purdue University confirmed the link between mass honeybee die offs (also called colony collapse disorder) and pesticides – especially systemic neonicotinoid pesticides.
The researchers investigated a rash of mass beehive deaths among bees in Indiana during the spring of 2010 and 2011. They analyzed the bodies of dead bees, along with the hives that were abandoned during the die-offs. The researchers also set up test fields with and without pesticides surrounded by hives to confirm the cause of the disappearing and dying bees.
Note that these neonicotinoid pesticides are also toxic for humans.
The analyses revealed the dead bees, hives of the dead and missing bees and the pollen collected by the dead bees prior to their deaths contained significant amounts of neonicotinoid pesticides clothianidin and thiamethoxam.
Meanwhile, their analyses of other healthy hives found that these pesticides were not present in the healthy hives, the healthy bees or their collected pollen.
As opposed to the spraying of pesticides, neonicotinoid pesticides are typically applied to plant seeds before they are planted. This coating makes pesticides systemic within the growing plant, and appear in the pollen of the plant. One of the biggest sources of these neonicotinoid-pesticide seeds is Bt corn, supplied by Monsanto.
BT corn and bee colony collapse
The planting of BT corn has grown significantly in the United States over the past few years – the same period the massive bee deaths of colony collapse have occurred. The 2010 corn plantings in the U.S. was the highest on record, with 88 million acres planted. 2011 was projected to be even higher.
Practically all of the corn planted within the U.S., with the exception of organic corn, is being planted using seeds coated with neonicotinoid pesticides. Organic corn plantings represents about 0.2% of the total corn plantings in the U.S. according to the National Agriculture Statistics Service.
These coated corn seed kernels contain significant pesticide content. One kernel of seed will contain enough systemic pesticides to kill more than 50% of bees exposed to the resulting plant, according to published LD50 values for honeybees – ranging from 22–44 ng/bee for clothianidin. This is called contact toxicity.
To test the connection between the bee deaths and the neonicotinoid Bt corn, the Purdue researchers planted corn fields in 2010 and 2011 with hives surrounding them. Half of the fields were planted in the neonicotinoid-treated corn, and half planted in untreated corn. The dead bees were found primarily in the hives surrounding the Bt corn fields, and the neonicotinoid pesticide residues from the dead bees and hives were primarily from the Bt corn pollen. This connected their toxicity and eventual death with the neonicotinoid pesticide-treated Bt corn.
Nicotinic acetylcholine receptor agonists
The killing mechanism of neonicotinoid pesticides is that they are nicotinic acetylcholine receptor agonists. The pesticide excites these receptors among insects, causing their death following neurotoxicity. The application of neonicotinoids to seeds has been banned among some European countries because European researchers discovered this same connection between mass bee deaths and neonicotinoid pesticides over the last decade.
The following brand names (some available in home garden sprays) also contain systemic neonicotinoids:
Bees pollinate more than 70 different crops – crops essential to our food supply. Without healthy bees, food supplies become more scarce. Recent data has revealed that more than a third of commercial beehives have been dying or gone missing every year since 2006 in the United States.
Concerned U.S. citizens are urged to take the following actions:
1) Check home pesticide products for neonicotinoids, and better yet, stop using chemical pesticides around the home and garden.
2) “Vote with your fork” by not buying foods made with genetically-modified Bt corn and other crops – which are often coated with neonicotinoid pesticides.
3) Write to congressional representatives and the Environmental Protection Agency. EPA’s Pesticide Information Center can be reached at [email protected] or 800-858-7378.
Krupke CH, Hunt GJ, Eitzer BD, Andino G, Given K. Multiple routes of pesticide exposure for honey bees living near agricultural fields. PLoS One. 2012;7(1):e29268.
Mommaerts V, Reynders S, Boulet J, Besard L, Sterk G, Smagghe G. Risk assessment for side-effects of neonicotinoids against bumblebees with and without impairing foraging behavior. Ecotoxicology. 2010 Jan;19(1):207-15.
Aliouane Y, El Hassani AK, Gary V, Armengaud C, Lambin M, Gauthier M. Subchronic exposure of honeybees to sublethal doses of pesticides: effects on behavior. Environ Toxicol Chem. 2009 Jan;28(1):113-22.
Lambin M, Armengaud C, Raymond S, Gauthier M. Imidacloprid-induced facilitation of the proboscis extension reflex habituation in the honeybee. Arch Insect Biochem Physiol. 2001 Nov;48(3):129-34.
Shah S. Behind Mass Die-Offs, Pesticides Lurk as Culprit. Yale Environment 360. 2010. 7 Jan.