Jim,


I'm so pleased that you continue this discussion with so many useful and thought-provoking points!!!  I for one find the topic very interesting, because as a physologist I am certain (big statement for a scientist) that the behavioral studies are right and I am also confident that there are subtle changes in a hive while it is "under the influence"....we just can't, or haven't, been able to detect those changes in a whole hive.  Given all the other problems bees are contending with at the same time, this does not seem an insignificant concern to me....witness the "nosema plus neonic" paper example (there are more papers on other related topics if anyone is interested).   Work down the road will undoubtedly continue to show synergies that prove there is reason to be concerned about neonics.  I think we must work to reduce prophylactic use of the neonics, we must work to better understand why bees on some crops (like curcubits, corn, apples) have greater problems than bees on our poster child crop, canola, and we must work to better understand the biochemistry of these things. However, the "big guns" in the bee world tell me over and over that I am (so to speak) missing the mountain for the molehill, that there are other more important things to think about, and that this topic is "tedious".  So I ask "does it matter"?   If it matters to the reader, read on.  If not, just skip my post(s).


It will take all of us working on different things to help solve all the bee problems out there. No one person can "save the bees" all by themselves.


So a few comments on your post.  First, a remark by Dick jogged my memory on biochemistry.  I think it is very unlikely that a second binding site will appear among IMI metabolites. It is possible, however, to make the existing one bind more aggressively to the receptor.


The extended time decay effect of those same longer-lived metabolites in the continued presence of the parent compound might, however, explain the "strong-milder-stronger" effect that you read about:

"The study also showed that mortality rose with low doses, fell with
intermediate doses, and rose again with high doses. The authors
suggest that at high doses imidacloprid and the metabolites that resemble it
(olefin, 5-hydroxy, and urea) fit into specific receptors
binding to the guianidine ring differently from the high-affinity receptors
binding to the 2-chloropyridinyl moiety, which all compounds may act on at
very low doses."

This is a very important statement and bears some thinking about.  I believe it was the bumblebee paper we read recently that says that there appear to be three different nicotinic acetylcholine receptor types in the bee, if such is the case it could also help explain the above statement.


Christina





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