Hello all,

Randy says:

"Food for thought is that if the bioavailable concentration did in actuality
(and I have no idea whether it can) reach the application rate, then
theoretically the farmer would no longer need to apply the product to get
the desired insect control.  When I pointed this out to a Bayer chemist, he
was fully aware, and suggested that that wouldn't make very good business
sense!"

Where I began on this topic was by saying that vertebrates "adapt" to nicotinoids (i.e. become "resistant") through changes at the receptor level.  These changes are reversible (think smokers).

If insect response to neonicotinoids is similar to the nicotinoid response by vertebrates (and why not), then, as they are exposed to increasing levels one would expect regular die-offs at first, because the toxic threshold would continue to be reached in spite of any increased threshold (adaptation).  However, if bees adapt as verts do, they will become "addicts" and tolerate much higher doses (and they are more like us than we knew: now we find out that they like caffeine!).  At that point of high tolerance, taking the drug AWAY is more "harmful" in the short term than continuing to feed the addiction.  I just don't know if insects react the same way.   Much of what we know about neurophysiology came from working on insects, so it wouldn't surprise me.

Anyone?

Another question:  Why are we thinking that treated corn (per se) is problematic except (potentially) at planting time?  Bees don't use corn as far as I know.  The only problem I can fathom is where corn dominates the landscape and there is no other forage for the bees.  I've spoken to second and third generation beekeepers from the midwest who have given up because there is no land left for bees to work in the places where their family beeyards used to be.

Finally, thanks for the spreadsheet work on neonic retention in the soil.  That's good thinking!  And soil residuals are important to know about.  Perhaps variations in short term (several years) build-up of soil toxicity explains regional variations that we are hearing about....in one area no bee kill problems, in another, high toxicity.  Maybe it's not so much the crop that is being grown but the type of soil it is grown on.

Christina

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