Common Pesticides Slowing Down Bees' Memory, Population

Commonly-used pesticides are turning off the learning ability of bees, slowing down population growth, says new research.

Researchers have now found that the chemicals neonicotinoids and coumaphos inhibit the bee's ability to learn and remember.

Previous research conducted on the chemical neonicotinoids had found that it causes population decline in bumble bee colonies.

The new research found that the chemicals directly attack regions in the brain that are associated with learning and memory. Bees exposed to the chemicals have a hard time remembering floral scents.

One of the new studies conducted on the subject by a team of researchers led by University of Dundee's Dr. Christopher Connolly is published in the journal Nature Communications. In this study, researchers examined the effects of neonicotinoid pesticides (used in agriculture) and coumaphos (used to kill a parasitic mite - the Varroa - that attacks honeybees).

Researchers assessed the amount of chemicals in the bees' brain. They found that the greater levels of the chemicals impaired brain function in bees. Also, when the chemicals were used in combination, their effect on the brain was greater.

Another new study conducted by Dr. Geraldine Wright and Dr. Sally Williamson at Newcastle University found that just four days of pesticide exposure resulted in 30 percent bees performing poorly in memory and learning tests. Their study is published in the Journal of Experimental Biology.

"Pollinators perform sophisticated behaviours while foraging that require them to learn and remember floral traits associated with food. Disruption in this important function has profound implications for honeybee colony survival, because bees that cannot learn will not be able to find food," said Dr. Wright in a news release.

However, a report from Food and Environment Research Agency (Fera) has said that there is no threat to bee health from these pesticides.

"Much discussion of the risks posed by the neonicotinoid insecticides has raised important questions of their suitability for use in our environment. However, little consideration has been given to the miticidal pesticides introduced directly into honeybee hives to protect the bees from the Varroa mite. We find that both have negative impact on honeybee brain function," said Dr. Connolly.