Poison and Genetics.
 Insecticides: Bees buzz around disorientated. Pesticides can harm bees. The most common of these are the neonicotinoids, which farmers use to treat and clean seed. They appear to have a negative effect on bees' orientation. Many respected researchers suspect that these are the triggers of colony collapse disorder. The bees leave the hive, lose their orientation, and do not return. Often, only the queen and a few workers remain, who then behave unusually. The bees stop feeding, neglect the larvae, and die shortly afterwards somewhere outside the hive.