I do hope others will view the presentation and critique it...there appear to be some glaring issues.

One of the most important things to understand about the written study (IMHO) is this:

"We used food-grade HFCS fortified with different levels of imdacloprid, mimicking the levels that are assumed to have been present in the older HFCS."

...again, this assumption does not seem supported by anything....it remains a hypothesis until someone measures imidacloprid in HFCS.

...continuing....

"The range of dosages used in this study ranged from 20 to 400 ug/kg..."

...a bit later on the same page (page 6):

"Considering that honey bees were diluting the concentration of imidacloprid fed th the hive with natural nectars foraged durring the HFCS feeding months (July to September), honey bees may have exposed to imidaclprid at the dosage lower than the 20 ug/kg in which is sufficent to render mortality in honeybees."

...my reading of the above is that the author knew that 20 ug/kg (20ppb) in feed would kill bees.  A series of assumptions leads the author to assume that free flying bees fed 20ppb would not encounter such a high concentration (even at night when no foraging is happening, even in extended rainy periods when no foraging is happening).  Feed is stored and used later...and it is very unlikely that all of it is diluted with real nectar/honey...more likely it is further concentrated (anyone know how much moisture the bees remove from food grade HFCS before capping?).

The long treatment period might replicate a migratory operation to some extent...moving from one imidacloprid treated crop to another...but the dynamics of storing feed in comb would be quite different.

In short, if the authors assumptions that the feed would always be diluted by other food sources is not 100% correct, then the author would expect bees feeding on even the lowest dose of the spiked feed to die....the higher dose was 20X what the author says should kill a bee.

deknow

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html

Guidelines for posting to BEE-L can be found at:
http://honeybeeworld.com/bee-l/guidelines.htm