In an extensive review, Blacquière et al. (2012) discusses 15 years of research on neonicotinoids on honey bees. In particular, they highlight the concentrations found in various substances (e.g., pollen, honey, honey bees) and their related side effects (lethal and sublethal).
One study they highlight found imidacloprid and its metabolite forms in honey bee bodies (11.2% of samples) Chauzat et al. (2011). It then mentions that other studies found no residues possibly due to the rapid metabolism of imidacloprid and its metabolites.
I'm wondering if honey bees are more frequently exposed to neonicotinoids, but our ability to capture this is due to the foragers rapid metabolism of imidacloprid.
Are there any current projects currently underway (through published abstracts/preliminary results) that you are aware of that investigates this question? It would be interesting to see a semi-field experiment that tracks the proportion of honey bees with concentrations of neonicotinoids after a controlled spraying event.
Blacquière et al. (2012)
http://www.springerlink.com/content/743617mk35kl4313/export-citation/
Chauzat MP, Martel AC, Cougoule N, Porta P, Lachaize J, Zeggane
S, Aubert M, Carpentier P, Faucon JP (2011) An assessment of
honeybee colony matrices, Apis mellifera (Hymenoptera Apidae)
to monitor pesticide presences in continental France. Environ
Toxicol Chem 30:103–111
There have been a number of studies in which actual nectar and pollen samples have been taken from treated plants. Suchail found poor absorption of Imd through the gut wall, but then rapid degradation. So not sure how much is degraded in the crop during transfer (I suspect little).
Other studies have analyzed recently stored nectar from the combs.
But I know of no studies that have directly investigated your question--how much is the neonic metabolized during transport via the crop.
Randy Oliver
ScientificBeekeeping.com
The review paper below probably contains some interesting references
Article Pesticide-laden dust emission and drift from treated seeds d...
The main sources of exposure are by direct spray or dust (which is not relevant, other than with planting dust), from nectar, or from pollen. There would be no bee metabolism of the active ingredients in pollen loads, so those would accurately reflect such exposure.
As far as nectar, you are correct in that the ai is rapidly degraded, at least if it makes it to the Malpighian tubules. Not sure about degradation in the crop, but measured concentrations in honey are generally low.
It is clear that whole-bee analyses are very time-sensitive, due to the rapid metabolism of the ai (half life of about 4 hrs). I know of no current research.
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