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From VOA Learning English, this is the Environment and Science Report.
A new study says a widely-used insecticide is damaging wild bee populations. Wild bees are important, because they pollinate crops and wild plants.
Environmentalists in the United States and Europe say chemicals called neonicotinoids are causing a drop in the number of bees.
These insecticides are among the most commonly-used worldwide. Farmers often use seeds treated with the insecticides.
The chemicals target insects that eat crops, and they do not spread beyond the field. But they do get into pollen and nectar, which is where the bees come into contact with them.
Maj Rudlof is a researcher at Lund University in Sweden. She led the neonicotinoids study.
She and other researchers studied bees in fields. Half of the fields were grown from seeds treated with neonicotinoids. The other half was grown with seeds that were not treated. She spoke about the results of the study in a video released by the journal Nature, which published it:
"The most dramatic result we found was that bumblebee colonies almost didn't grow at all at the treated sites compared to the controlled sites."
She says there were about half as many wild bees per square meter in treated fields as in untreated ones.
Dennis vanEngelsdorp is an entomologist, a scientist who studies insects. He works at the University of Maryland. He was not involved with the research on neonicotinoids. But, he says banning the chemicals may not be the answer. He says they are not as bad as other insecticides. He spoke to VOA on Skype.
"In many cases, (neonicotinoids) are actually the safest alternative and so by banning it, what you're doing is forcing farmers to use products that may either be just as bad or worse."
He says farmers often use the chemicals too much, and that may be hurting bees. Mr. vanEngelsdorp thinks farmers might not need to stop using neonicotinoids completely. He says the chemicals should be used more sensibly, or, in other words, only when necessary.
The same chemicals are thought to be linked to a problem with European honeybees – the bees kept by farmers to pollinate crops. The problem is called Colony Collapse Disorder. The worker bees from a beehive, or colony, suddenly disappear. Farmers do not see the dead bees around the hive.
A United States Department of Agriculture report included information about the effects of neonicotinoids. It said the chemicals make the bees more likely to become sick. The bees cannot fight the viruses that commonly affect them.
And that's the VOA Learning English Environment and Science Report. I'm Marsha James.
