Honeybees are in great trouble, according to researchers from Purdue University. They discovered the little insects collect their pollen from non-crop plants, which are often infected with urban and agricultural pesticides during the growing season.
The findings published in Nature Communication were part of the study led by Christian Krupke, professor of entomology at Purdue University, and Elizabeth Long, a post-doctoral researcher.
For the study, the team collected pollen samples from 3 locations of honeybee hives in Indiana for over 16 weeks. They were particularly interested in finding which pollen sources were preferred by the honeybees during the season, and whether this pollen is contaminated with pesticides.
Their pollen collection comprises samples from 30 plant families; results showed that 31 pesticides were found in pollen from the untreated cornfield, 29 pesticides in pollen from the treated cornfield, and 29 pesticides in pollen from the meadow site.
According to Krupke, pyrethroids were the pesticides found in the pollen in greatest quantities; they are synthetic products used in a household to repel insects. At the same time, the pollen collected from soybean and corn pollen had high amounts of neonicotinoids, which are toxic to bees.
Researchers also found other pesticides, such as phenothrin – used to keep ticks and fleas away – and prallethrin, for deterring wasps and hornets.
Krupke explained said that even though crop pollen was only a small part of their samples, the bees covered by the study were definitely exposed to a wider range of chemicals than they previously thought.
He added that the high amounts of different pesticides found in pollen samples were also surprising. However, agricultural chemicals are only part of the overall problem.
Homeowners and urban landscapes are also big contributors to the issue, even though hives are usually adjacent to crop fields for this very reason.
The findings are a true illustration of the constant exposure of honeybees to several pesticides during the season, according to Long. The study is meant to be a call to action, revealing how pesticides are a long-term stress factor for bees.
She further explained that if you care about bees as a homeowner, you should only use insecticides when it’s absolutely necessary. Otherwise, you should be aware that no amount of prevention will keep the bees away from coming into contact with them.
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