The phenomenon of colony collapse disorder (CCD) in honey bees is a recent one that has plagued honey bee populations in North America. CCD is a recent condition that is characterized by the disappearance of honey bees from the hive. This has long puzzled investigators. A number of different causes have been proposed including pesticides, microbial or parasitic infection and environmental degradation.
Since honey bees significantly contribute to plant propagation through pollination, It is important to uncover the actual cause of CCD so that this situation can be addressed and remedied. Of the possible candidates as cited above, pesticides have long been suspected of playing a leading role. Farming practices often involve the wide use of systemic pesticides. Systemic agents permeate all the tissues of a plant ultimately contaminating the nectar and pollen on which the bees rely. In addition, honey bees heavily utilize common blooming crops including oilseed rape, maize and sunflower that are commonly exposed to pesticides.
Although pesticide manufacturers are required to monitor the mortality of unintended life forms in the field, there is growing evidence that sub lethal doses may adversely impact behavioral problems in aging honey bees especially in regard to navigational skills. There is a class of insecticides, the so-called, "Neonicotinoids" routinely used to protect crops against aphids that are strong candidates for having an adverse impact upon honey bees. The reason for this possible connection is that pesticides of this class selectively bind to nicotinic acetylcholine receptors that are essential for a properly functioning nervous system in insects.
Dr. Mickael Henry and his colleagues from the Institut de la Recherche Agronomique in Avignon, France have shown that, "nonlethal exposure of honey bees to thiamethoxam (neonicotinoid systemic pesticide) causes high mortality due to homing failure at levels that put a colony at risk of collapse."
This finding is of crucial importance, for it provides direct evidence of the actual causative agent in CCD. These finding should provide impetus for a reexamination of the widespread use of nonicotinoid pesticides that are currently in worldwide use.