Interesting 2014 study linking Neonics and CCD.

“Bees from six of the 12 neonicotinoid-treated colonies had abandoned their hives and were eventually dead with symptoms resembling CCD,” the team wrote. “However, we observed a complete opposite phenomenon in the control colonies.” Only one control colony was lost, the result of infection by the parasitic fungus Nosema and in this case the dead bees remained in the hive.

I look forward to a longer study perhaps with a greater number of hives.

Honeybees abandoning hives and dying due to insecticide use, research finds
Sub-lethal exposure to neonicotinoids impaired honey bees winterization before proceeding to colony collapse disorder