A commonly used insecticide, and possibly an increasingly widely used form of that pesticide, could be a causal factor in bee colony collapse. It is not 100% certain that this pesticide’s effects can be counted as one of the causes this problem, but there is a very good chance that neonicotinoids can cause a drop in hive population, and thus, should be examined to see if there is a relationship in some cases. From the paper’s abstract:
Nonlethal exposure of honey bees to thiamethoxam (neonicotinoid systemic pesticide) causes high mortality due to homing failure at levels that could put a colony at risk of collapse. Simulated exposure events on free-ranging foragers labeled with an RFID tag suggest that homing is impaired by thiamethoxam intoxication. These experiments offer new insights into the consequences of common neonicotinoid pesticides used worldwide.