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Tuesday, November 19, 2013

Pesticides & Pollinator Decline

Bees have been dying off in droves around the world since the mid-1990s. First in France, then in the U.S. and elsewhere, colonies have been mysteriously collapsing with adult bees disappearing, seemingly abandoning their hives. In 2006, about two years after this phenomenon hit the U.S., it was named “Colony Collapse Disorder,” or CCD. Each year since commercial beekeepers have reported annual losses of 29% - 36%. Such losses are unprecedented, and more than double what is considered normal.
While wild pollinators like bats and bumble bees are also facing catastrophic declines, managed honey bees are the most economically important pollinators in the world. According to a recent U.N. report, of the 100 crops that provide 90% of the world's food, over 70 are pollinated by bees. In the U.S. alone, honey bees’ economic contribution is valued at over $15 billion.

What the bees are telling us

State of the Science

State of the Science: Pesticides & BeesPAN's report Honey Bees and Pesticides: State of the Science presents findings from dozens of scientific studies, focusing on the link between pesticides and CCD. Download here»
U.S. commercial beekeepers report that their industry is on the verge of collapse, and farmers who rely on pollination services are increasingly concerned. It's unlikely that such a collapse will directly result in a food security crisis, but crop yields would decline signficantly, and more acres of land would need to be put into production to meet demand.[1] With most fruits, many vegetables, almonds, alfalfa and many other crops all dependent upon bees for pollination, the variety and nutritional value of our food system is threatened.
In addition to their agricultural value as pollinators, honey bees are a keystoneindicator species. Their decline points to (and will likely accelerate) broader environmental degradation in a kind of ripple effect. Pollinator population declines are thus a disproportionately important piece of the current collapse in biodiversity that seven in ten biologistsbelieve poses an even greater threat to humanity than the global warming which contributes to it. Little-known fact: we are today living through a sixth mass extinction. During the last one, dinosaurs went extinct.
As indicator species, honey bees are sounding an alarm that we ignore at our peril. Among their lessons: industrial agriculture has gone off the rails, kicking the pesticide treadmill into high gearwith a new class of dangerous systemic pesticides while regulators were asleep at the switch.

Neonicotinoids at-a-glance

  • Very persistent in soil & water soluble.
  • Systemic pesticides applied at the root (as seed coating or drench) & then taken up through the plant’s vascular system to be expressed in pollen, nectar & guttation droplets(like dew) from which bees then forage & drink.
  • Systemics on food cannot be washed off.
  • Nicotine-like, neurotoxic insecticides that bind to nicotinic acetylcholine receptors in insects’ brains.
  • Bees have a particular genetic vulnerability to these & other pesticides because they have more of these receptors, as well as more learning & memory genes, & fewer genes for detoxification.
  • Widely used on more than 140 crop varieties, as well as on termites, flea treatments, lawns & gardens.
  • Fastest-growing class of synthetic pesticides in history. Imidacloprid is Bayer Crop Science's top-sellingproduct.

What we know

Much has been made over the "mystery" surrounding CCD, but in recent years two points of consensus have emerged:
  1. Multiple, interacting causes are in play – key suspects include pathogens, habitat loss and pesticides; and
  2. Immune system damage is a critical factor that may be at the root of the disorder.
Meanwhile, a new class of systemic, neurotoxic pesticides that are known to be particularly toxic to honey bees has rapidly taken over the global insecticide market since their introduction in the 1990s: neonicotinoids. Neonicotinoids (like imidacloprid and its successor product clothianidin) are used as seed treatments in hundreds of crops from corn to almonds, as well as in lawn care and flea products. These products persist for years in the soil, and, as systemics, permeate the plants to which they are applied to be expressed as pollen, nectar andguttation droplets (like pesticide dew).
Honey bee exposure to this class of pesticides is, in other words, nearly pervasive – and in the U.S. the rate of seed treatment with these insecticides increased five-fold around the same time CCD hit the U.S.
Recent science shows that extremely low dose exposures to neonicotinoids undermine immunity – rendering honey bees more susceptible to pathogens. And beekeepers in the U.S. and Europe have, for years, been asking governments to pull or restrict this class of pesticides because they believe them to be harming hive health.  

Decisive action is overdue

Governments in Italy, Germany, France and elsewhere have already taken action against neonicotinoids to protect their pollinators. And beekeepers there are reporting recovery. Yet regulators in the U.S. remain paralyzed, apparently captive to industry-funded science and a regulatory framework that finds chemicals innocent until proven guilty.
It seems that only massive public outcry will compel U.S. policymakers to take action on a timeframe that is meaningful for bees and beekeepers. With one in every three bites of food dependent on honey bees for pollination, the time for decisive action is now.
[1] Spivak M, Mader E, Vaughan M, et al., The plight of the bees, Environmental Science and Technology (45) 34-38, 2011.