Commonly Used Pesticides Affect Bees' Ability To Learn: Study
Some commonly used pesticides are causing damage to honeybee brains, suggest two new studies.
Researchers have found that two pesticides commonly used in agriculture target the learning centre of the bee brain, causing a loss of function.
For their study, University of Dundee's Dr Christopher Connolly and his research team probed the effects of neonicotinoid pesticides (that are commonly used on crops) and coumaphos pesticide (that is used in honeybee hives to kill the Varroa mite that attacks the honey bee) on bees' brains.
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They recorded the brain activity of the bees by exposing them to pesticides in the lab, at levels shown to occur in the wild. They found that both types of pesticides target the area in the bee brain that is involved in learning, affecting the bees' memory. Bees become slower in learning and even forget floral scents.
Moreover, the effects of both pesticides used in combination were much greater, said the researchers. The findings of the study are published in the journal Nature Communications.
Another study by researchers Dr Geraldine Wright and Dr Sally Williamson at Newcastle University, UK, revealed the same results as Connolly and his team.
When the bees were exposed to combinations of these pesticides for four days, the researchers found that about 30 percent of honeybees failed to learn or performed badly in memory tests. For their experiments, the researchers used the levels of pesticides that could be seen in the wild, but this time they fed a sugar solution mixed with appropriate levels of pesticides.
"Pollinators perform sophisticated behaviors while foraging that requires 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," Wright said in a press statement.
The findings of this second study appear in The Journal of Experimental Biology.
But, another report by UK's Food and Environment Research Agency (Fera) have concluded that the pesticides have no major impact on bees.
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