New research reignites concerns that pesticides are harming bees: The Washington Post

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By Chelsea Harvey.

A common pesticide could hinder bumblebees’ ability to pollinate plants, says a new study — and that could be a big problem for both agriculture and the natural ecosystems that depend on the bees for survival.

paper published Wednesday in the journal Nature tested the effects of a pesticide called thiamethoxam on the ability of bumblebees to pollinate apple trees. The study suggested that, at certain levels, the pesticide can have negative impacts on the bees’ pollination abilities, causing colonies to visit fewer flowers and return with less pollen, and resulting in apples with fewer seeds. These results could indicate poor fruit quality and a risk of decreased agricultural output down the line, fueling the fire in an ongoing debate over how certain pesticides affect the environment and whether their continued use should be permitted in the U.S.

The researchers used three groups of bees in their experiment. They exposed the first two groups to two different “field-realistic” levels of the pesticide, or amounts that are actually used by farmers to protect their crops — 2.4 parts per billion and 10 parts per billion. They didn’t expose the third group to any pesticides at all. Colonies exposed to the 10 parts per billion experienced the strongest effects.

“One of the important things about our work is that it highlights the importance of pollination services,” said lead author Dara Stanley, who was a researcher at Royal Holloway University of London at the time the study was conducted, and will soon be starting a position at the National University of Ireland Galway. According to Stanley, this paper is among the first studies to examine the way pesticides affect bumblebee pollination services, and not just bumblebee biology or physiology.