On Thu, Mar 29, 2012 at 9:54 AM, Jonathan Getty <[log in to unmask]> wrote:
>
> http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0030023#s1
>
Thanks-
For me the key quote is:
These documented concentrations are still more than twenty-five to fifty
> times higher than the residues found in the nectar of sunflowers (*
> Helianthus*, 1.9 ppb) [8]<http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0030023#pone.0030023-Schmuck1>.
> Treatment with the lowest dose of imidacloprid (0.15 ng; 11.5 ppb), which
> is about five-fold higher than any residues found in nectar, had no
> recognizable effect on foraging behavior. Nevertheless, bees may be exposed
> to almost 100-fold higher doses than tested in our trials, as shown in a
> study concerning the insecticide contamination of guttation drops, xylem
> fluids that are excreted at the leaf margins [7]<http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0030023#pone.0030023-Girolami1>in seed dressed crops. It remains unclear, though, if water foragers
> collect these fluids in the field.
>
Which is interesting in that we may not be looking at the right thing as
both nectar and pollen have a negligible effect because of concentrations
found, but "guttation drops" may be an issue.
But, that remains to be shown because of the continued observation that,
when there are controlled studies by corn planters and canola, the colonies
do not show ill health, at least not measurable.
This definitely is a commercial beekeeper problem compared to a side-liner
or hobby beekeeper since you need a mono-culture that is treated with
neonics. There are too many nectar sources around to even get close to the
concentrations found with a single crop (even thought the study marginally
approximated it).
Good study. Will be interesting to see the reaction of both sides since it
has a little for both, assuming they read it before broadcasting their new
bulletins. My guess is selective editing will be the first release.You need
look no further than the next paragraph-
This is the first study on foraging behavior of honeybees that presents
> sub-lethal effects after acute oral treatment with clothianidin. Dosages of
> 0.5 ng (38 ppb) negatively influence the foraging behavior and low dosages
> (0.05 ng; 3.8 ppb) can have effects on certain aspects of foraging behavior
> even if they did not have any significant effects on the number of feeder
> visits or on the total foraging time. Clothianidin elicited detrimental
> sub-lethal effects at somewhat lower doses (0.5 ng/bee) than imidacloprid
> (1.5 ng/bee). Bees disappeared at the level of 1 ng for clothianidin, while
> we could register the first bee losses for imidacloprid at doses exceeding
> 3 ng. This indicates a stronger impact of clothianidin compared to
> imidacloprid, which is in agreement with previous reports that both oral
> [7]<http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0030023#pone.0030023-Girolami1>and contact toxicity
> [25]<http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0030023#pone.0030023-Bailey1>levels are lower for clothianidin.
>
You need to know what dosages are actually found in nectar and pollen to
arrive at the first paragraph, otherwise, the second paragraph could easily
be used in an inflammatory manner.
Bill Truesdell
Bath, Maine
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