Pesticides alter bees' brains: study

A particular class of pesticides can kill brain cells in bees, rendering them unable to learn, gather food and reproduce, scientists say.
Researchers said pesticides called neonicotinoids wreak havoc on the bee populations, ultimately putting some crops that rely on pollination in jeopardy.
They suggest that the effects of these pesticides on bee colonies may be reversible by decreasing or eliminating the use of these pesticides on plants pollinated by bees and increasing the availability of "bee-friendly" plants available to the insects.
The study, published in The FASEB Journal, was conducted by Christopher N Connolly, from the Medical Research Institute at the Ninewells Medical School at the University of Dundee in UK, and colleagues.

They fed bees a sugar solution with very low neonicotinoid pesticide levels typically found in flowers (2.5 parts per billion) and tracked the toxins to the bee brain.
They found that pesticide levels in the bees' brains were sufficient to cause the learning cells to run out of energy. Additionally, the brain cells were even vulnerable to this effect at just one tenth of the level present.

When the ability of the bee's brain to learn is limited, the bee is unable to master key skills such as recognising the presence of nectar and pollen from the smell emitted from flowers.

In addition, scientists fed bumblebee colonies this same very low level of pesticide in a remote site in the Scottish Highlands where they were unlikely to be exposed to any other pesticides.
They found that just a few of the exposed colonies performed well, colonies were smaller, and nests were in poor condition with fungus taking over.
This further suggests that bumblebees exposed to this type of pesticide become poor learners, become unable to properly gather food, and become unable to properly nurture the next generation of bees, researchers said.