http://www.digitaljournal.com/article/322138

Pesticide risk for Bees

Posted Mar 31, 2012 by Tim Sandle
A pesticide, commonly used since the 1990s, has been shown to affect bee colonies and can potentially lead to the collapse of the entire colony. This news has led to calls for greater pre-approval testing of pesticides.
Bee a Kew gardens
Bee a Kew gardens
A certain type of common pesticide, called neonicotinoids, are affecting bee populations around the world. As BBC Science reports, this is mainly through creating disorder throughout bee colonies.
The risks of pesticides comes from two separate studies.
The first study showed that bumble bees exposed to a neonicotinoid produced fewer queens. The research team examined bumble bees who eat pollen laced with the pesticide over a two week period. It was shown that the bees weighed less nd thus worked less hard, bringing less food back to the hive. The colonies also produced far fewer queens.
In the second study, honey bees exposed to the pesticide had trouble finding their way back to the hive. The researchers found this out by tracking honey bees with special chips. Often the honey bees failed to return home and died. Eventually, when a sufficient number of honey bees were exposed to the pesticide, the population fell to an unsustainable level and the hive collapsed.
The conclusion of both studies was the over-exposure to the pesticides posed a major problem and could cause the collapse of entire colonies. The bee die-off does not just make for a lack of honey in the world. Bees are hugely important pollinators.
The pesticides in question, neonicotinoids, began to be used from the 1990s. They are a class of insecticides with a common mode of action that affects the central nervous system of insects, causing paralysis and death. They are typically used to protect crops by killing aphids and butterflies.
Both research papers argue that insufficient toxicity tests are carried out before pesticides are released for use.