Bees and Pesticides (again)

May 23 2012 Published by under Uncategorized

The same day that I published my piece about bees and pesticides, the Pesticide Action Network released a report titled Honey Bees and Pesticides: State of the Science. It's basically an annotated bibliography of some of the major papers over the last 9 years.

Their introduction was... well:

"Two increasingly intractable sides have emerged in this controversy:
beekeepers and environmental health advocates vs. pesticide companies and the scientists supported by them."

That Us vs. Them language is really disturbing.  I happen to be a scientist, and a beekeeper, and an environmental health advocate. I don't always agree with everything PAN does, but I agree much more than I disagree.  (It's also a little odd that they would begin with this sort of divisive language, and then....turn to the products of scientists to prove their point.)

It didn't take long before I was accused of being a "pesticide shill" after my last post cautioning that neonicotinoids are not the sole cause of colony collapse disorder.  Trust me, I am sooooo not raking in the big chemical daddy bucks.

I've never said that pesticides are safe, or that they don't harm bees--just that the story is complex.

Nuance: I Haz It.  

shades of grey kitten

Personally? I think the biggest threats to honey bees are a combination of many factors--and to focus on one exclusively will not help us solve the problem. I WISH that the issue really was just the neonicotinoid class of pesticides, because that would give us an easy "off" switch for the problem.  Ban the pesticides, bees come back.  Solved.

But even if we did ban these pesticides--and dealt with the giant economic upheaval in agriculture that would accompany that, BTW--honey bees aren't going to recover, because they still are besieged by mites, and viruses, and fungal disease, and the pesticides we apply to the bees directly to control those problems. That also doesn't begin to cover the issues with bee nutrition and forage diversity.

There is clearly a pesticide problem with bees–even if we can’t fully quantify it right now. I want to steer you away from the PAN report to another, less well known and excellent summary of this class of pesticides on bees.  The Xerces Society white paper, A Review of Research into the Effects of Neonicotinoid Insecticides on Bees, with Recommendations for Action, had this to say about CCD:

“There is no direct link demonstrated between neonicotinoids and the honeybee bee syndrome known as Colony Collapse Disorder. However, recent research suggests that nenonicotinoids may make honey bees more susceptible to parasites and pathogens….which has been implicated as one causitive factor for CCD.”

The Xerces paper is probably the best review of the recent research that you are going to find.  Not only is it written by Xerces scientists, who are folks what really know their bees, it also was reviewed by several other bee researchers I have a great deal of respect for.

Xerces thoroughly documents what we know about these pesticides and bees–and, unfortunately, we don’t know nearly enough. Most of the published research focuses on honey bees, rather than the native bee species in the US.  (Honey bees are an introduced species in North America).  That means we don’t have much data to work with to figure out how different bee species will be affected.  When you look at this chart of pesticide effects on native bees...we have no freakin' clue how they are affected.

Personally, I found the most disturbing piece of the Xerces report to be their discovery of how many of these neonicotinoid insecticides are available over the counter to homeowners.  Calculating pesticide application rates is one of the toughest parts of farming (or pesticide applicator exams), and Xerces does the math to uncover some startling facts:

  • “Products approved for homeowners to use in gardens, lawns, and on ornamental trees have manufacturer-recommended application rates up to 120 times higher than rates approved for agricultural crops. 
  • Many neonicotinoid pesticides that are sold to homeowners for use on lawns and gardens do not have any mention of the risks of these products to bees, and the label guidance for products used in agriculture is not always clear or consistent.
  • Neonicotinoids can persist in soil for months or years after a single application. Measurable amounts of residues were found in woody plants up to six years after application.”

That is really scary.

Xerces raises some very important questions about what this means for our native bees that are already struggling with habitat loss and a spill-over of parasites and pathogens from introduced bee species. Butterflies, beetles, and flies also drink nectar and feed on pollen–pretty much any of our pollinators, including hummingbirds, could be affected if they feed on trees and plants treated with these insecticides.

I would like to see new labeling so consumers know that these products have the potential to kill bees and other pollinators, as well as a review of application rates for over-the-counter formulations.

bee photo

Unfortunately, because neonicotinoid pesticides are so very useful in agriculture, there are no easy answers. The things that make these compounds so very well suited for so many purposes–their ability to remain stable for a long time and spread through plant tissues–are also why they pose dangers for pollinating insects.

Additional Reading: 

(Thanks to Artologica for the LOLcats!)

2 responses so far

  • [...] post at Scientopia: even more discussion of pesticides and bees!… [...]

  • spit says:

    The more we look at complex systems breaking down, the more we lack an easy yes/no.

    And that really, um, bugs some people.

    I don't know either, of course, but would suspect that this set of chemicals could disrupt any number of things over time with enough exposure, just based on what I know about nicotinoids in the insect brain. Including bees' neural control of immune function. Which would lead to a whole host of other mess.

    The safety here, I would think, would have to rely on them not taking much in -- if that's not the case, then it's almost certainly involved in bee health decline, even if it isn't simple-direct causal to CCD. What we really seem to need to know is the means by which they're having a steady low level dose, so far as I can tell -- correct me if I'm behind or thinking wrong, of course.

    CCD might not simply go poof without that, but it's certainly not helping anything if they're getting all screwed up in their cholinergic regulation over time with constant exposure.