The fact that they were absorbing neonics even before corn was planted, and that pollen was being preferably gathered not from the treated corn but from other plants around the field suggests that the water-soluble neonics were getting into ground water and being absorbed by surrounding wild flowers and trees, that is spreading into the environment beyond the confines of the corn itself.
A study funded by Bayer and Syngenta confirms that neonicotinoid insecticides kill queen and worker bees.