A common insecticide really does contribute to the death
of bees, according to a large-scale field study. This helps set to rest
some of the controversy over the use of the chemicals.
The type of insecticide in question, called neonicotinoids, is often used to coat crops. In a study published today in the journal Science,
researchers grew rapeseed in 33 sites across Germany, the United
Kingdom, and Hungary. They coated the crop with neonicotinoids,
introduced various bee species to the area, and monitored the health of
the colonies compared to control groups. (These chemicals were made by
the companies Bayer CropScience and Syngenta, which helped fund the
study.) The bees who lived near the plants treated with neonicotinoids
had more trouble surviving the winter.
Before now, we were still unsure just how harmful these particular insecticides were. In 2013, the European Union banned the chemicals due to concerns that they were killing bees, which are crucial for agriculture. Currently, bee populations are falling worldwide. Still, the ban has been controversial, with some critics saying that the simulations in earlier studies were unrealistic.
Today’s study is one of the first large-scale field
reports. Honeybees in the United Kingdom had difficulty surviving to
begin with, but survival was lowest near crops treated with
neonicotinoids the year before. Similarly, in Hungary, colony numbers
fell by 24 percent by following spring. However, there was no effect in
Germany.
The authors suggest that the different results may be
because of the different climates naturally found in the three
countries. Hives in Germany are usually larger to begin with and closer
to a wider range of flowers than those in the UK and Hungary. Overall,
though, because this was a field study that mimics real-world conditions, the study goes a long way toward settling the debate on these chemicals, even if the news isn’t good.
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