Medhat pointed out a NEW paper by our man at Harvard, Dr. Chensheng Lu.

http://www.bulletinofinsectology.org/pdfarticles/vol67-2014-125-130lu.pdf
http://tinyurl.com/lgvec22

“…we administered  258  µg  of  imidacloprid … or  clothianidin  in  1.9
liter  (0.5  gallon)  of  sucrose  water  and HFCS  to  the  treated
colonies  each  week,  respectively, for  thirteen  consecutive  weeks
ending  on  September 17th 2012.”

Back of the envelope time:

258 µg in 1.9 liters of feed = 258/1.9 = 135.78 µg/L.

1 µg/L =  1 ppb, so 135 µg/L =  135 ppb

Bayer’s own FAQ says that the acute oral LD50 for Imidacloprid is 0.005
µg/bee, which equals 192 ppb
http://bee-quick.com/reprints/imd/BayerFAQ.pdf‎
http://tinyurl.com/kjrrsoh

Is the difference between 192 ppb and 135 ppb worth pondering?  Or even
discussing?  This looks like a fatal dose level for almost, but not quite
half the bees who are fed the dose.

For clothiandin, the EPA says that the LD50 > 0.0439 µg/bee, roughly 10x the
LD50 for Imidacloprid.

http://www.epa.gov/opp00001/chem_search/reg_actions/registration/fs_PC-04430
9_30-May-03.pdf
http://tinyurl.com/kq2j8qt

So, my rough calculations say that  the study should show very bad news for
Imidacloprid-treated hives and perhaps some brood impact on the
Clothiandin-treated hives, but certainly less mortality.  While they did NOT
kill the Imidacloprid-treated hives anywhere near as quickly as I would have
expected, they did see worse results for Imidacloprid.

Note that the LD50 is the dose where half the bees die quickly, so if you
get anywhere near the LD50 dose, you should still see significant acute
mortality.

"The Return of Dr. Lu"... too bad Vincent Price has died, as he would be the
best person to play the lead role in the film version of something with that
sort of a name.

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