Read the whole thing. It is not a pretty article. Bob, it explains part of why you keep losing your bees. Anyone in agricultural areas where Sulfoxaflor is being sprayed has bees that can't thermoregulate their hive. And the EPA released it, it is a neonic, and it kills on the sneaky side...
I Believe I've posted this link in the past, but for those who lost colonies last winter, this is a pretty good check list to follow:
http://nybeewellness.org/wp-content/uploads/2014/04/winter_deadout_key_2-24-14_final_draft-2.pdf