Dizzy as a bee

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Photo by Guerin Nicolas/Creative Commons

As titles go, that’s a bit glib for a post like this, but “the world’s going to hell in a hand-basket” seemed too obvious.

A friend forwarded this item from last week’s Huffington Post (Canada) about widespread contamination of western Canadian prairie wetlands by a class of neurotoxic pesticides known as neonicotinoids (sometimes called “neonics”).  A University of Saskatchewan biologist, Christy Morrissey, has found that neonicotinoids are showing up in wetlands in her study area in concentrations “at least three to four times higher than what has been deemed habitable for insects.”  And it is not just a regional problem; Morrissey estimates conservatively that tens of millions of acres in western Canada have been treated with neonicotinoids, and that – based on her team’s samples – 80 to 90 percent of surrounding wetlands are contaminated.

This is a really big deal.  There is mounting evidence that neonicotinoids are moderately to highly toxic to several species of bees – causing changes in flight and foraging behavior, navigational abilities, cognition (yes, you read that correctly: bee cognition), communication, metabolism, and appetite.  Not surprisingly, neonicotinoids have have been implicated in honeybee Colony Collapse Disorder (CCD).  From Elizabeth Kolbert’s 2012 New Yorker article:

“In the first of the new studies, published online in the journal Science, British scientists raised bumblebees on a diet of pollen, some of which had been treated with a widely used neonicotinoid called imidacloprid.  Those colonies that had received the treated pollen suffered significantly reduced growth rates and produced dramatically fewer new queens.  In the second, also published in Science, French researchers equipped honeybees with tiny radio-frequency tags.  They fed some of the bees sucrose treated with thiamethoxan, another commonly used neonicotinoid.  Then they let the bees loose to go foraging.  The bees that had been exposed to thiamethoxan were much less likely to return to their hives.  ‘We were quite surprised by the magnitude of the effect,’ said one of the study’s authors, Mickaël Henry, of the French National Institute for Agricultural Research in Avignon.

In a third study, to be published soon in the Bulletin of Insectology, seemingly healthy honey colonies were fed high-fructose corn syrup that had been treated with imidacloprid.  Within six months, fifteen out of the sixteen hives that had been given the treated syrup were dead.  In commercial beekeeping operations, bees are routinely fed corn syrup, and corn is routinely treated with neonicotinoids.”

There is also evidence that neonicotinoids are toxic to songbirds.  According to a report by ecotoxicologist Pierre Mineau and environmental lawyer Cynthia Palmer [p3]:

“A single corn kernel coated with a neonicotinoid can kill a songbird.  Even a tiny grain of wheat or canola treated with the oldest neonicotinoid, imidacloprid, can poison a bird.  As little as 1/10th of a corn seed per day during egg-laying season is all that is needed to affect reproduction with any of the neonicotinoids registered to date.”

And there is increasing evidence that neonicotinoids are reducing populations of so-called “beneficial insects” (beneficial from an agricultural point of view; we’ll save discourse on the social construction of “beneficial insect” categories for another day).  Here is just a small sampling of the findings detailed in Beyond the Birds and the Bees: Effects of Neonicotinoid Insecticides on Agriculturally Important Beneficial Invertebrates, another literature review/report by the Xerces Society [p8]:

  • Dinotefuran sprays at label rates were highly toxic to a parasitoid wasp (Leptomastix dactylopii) and spray applications of acetamiprid, clothianidin, and dinotefuran were toxic to mealybug destroyer beetles (Cryptolaemus montrouzieri) (Cloyd and Dickenson 2006).
  • Acetamiprid spray at the field rate was toxic to the predatory plant bug Deraeocoris brevis (Kim et al. 2006).
  • Acetamiprid is toxic to a predatory thrip (Scolothrips takahashi ) and a lady beetle (Stethorus japonicus) (Mori and Gotoh 2001, as cited in Naranjo and Akey 2005).
  • Imidacloprid spray applied at field rates caused significant mortality to nymphs and adults of the predatory stink bug Podisus maculiventris (De Cock et al. 1996).
  • Imidacloprid spray treatment to pest eggs only slightly reduced emergence of Trichogramma cacoeciae, a parasitoid wasp, but direct exposure to spray caused high mortality of the adult parasitoid wasps (Saber 2011).
  • Under lab conditions, acute contact applications of imidacloprid caused increased mortality in predaceous true bugs and lady beetles, although not to two species of predatory mites (Mizell and Sconyers 1992).
  • Parasitoid wasps confined with citrus leaves that were treated with either imidacloprid or thiamethoxam had significantly higher mortality (Prabhaker et al. 2011).

Neonicotinoids are currently the pesticide of choice – the most widely used in the world; the US EPA continues to approve them (Mineau and Palmer argue that the EPA has “greatly underestimated this risk using scientifically unsound, outdated methodology that has more to do with a game of chance than with a rigorous scientific process.  Major risk concerns raised by scientists both inside and outside the agency appear to have gone unheeded in agency registration decisions” [p3].)  Industry lobbyists such as CropLife Canada defend neonicotinoids as having “extremely low toxicity to humans…(and) other mammals as well as birds and fish.”  And they are in fact much less toxic to mammals and most birds than older pesticides.  But they are far from benign.  Their effect on pollinators (bees, bumblebees, butterflies, beetles, etc.), other insects, and aquatic invertebrates could be ecologically devastating, as Dr. Henk Tennekes warns when he refers to the widespread use of neonicotinoids and other systemic pesticides as a “disaster in the making.”

There are a lot of factors converging to reduce the density and diversity of insects in worrisome ways.   But this is one we can begin to get a grip on.  What can you and I do?

  1. Stop using neonicotinoids in your garden and on your lawn.  Avoid these products.  And select pollinator-friendly plants!
  2. Tell retailers to stop selling neonicotinoids; there’s a Sum of Us petition here.
  3. Tell the EPA to restrict the use of neonicotinoids.
  4. Ask your member of Congress to support the Save America’s Pollinators Act.
  5. Keep yourself informed by reading Henk Tennekes blog.
  6. Support the efforts of groups like the Xerces Society, working to protect invertebrates while educating educable vertebrates about what happens to an ecosystem when the bugs are gone.

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