Neonicotinoids (Imidacloprid and Clothianidin) disrupt bees ability to orient and return to hive. Sure wish Bayer would have found this out before they started going to local associations and saying these substances are safe for use.
Sorry the link is in german: http://www.spiegel.de/wissenschaft/natur/pestizide-machen-bienen-orientierungslos-a-959820.html
Sorry the link is in german: http://www.spiegel.de/wissenschaft/natur/pestizide-machen-bienen-orientierungslos-a-959820.html