A Purdue University study shows that honeybees collect the vast majority of their pollen from plants other than crops, even in areas dominated by corn and soybeans, and that pollen is consistently contaminated with a host of agricultural and urban pesticides throughout the growing season.
Christian Krupke, professor of entomology, and then-postdoctoral researcher Elizabeth Long collected pollen from Indiana honeybee hives at three sites over 16 weeks to learn which pollen sources honeybees use throughout the season and whether they are contaminated with pesticides.
The pollen samples represented up to 30 plant families and contained residues from pesticides spanning nine chemical classes, including neonicotinoids — common corn and soybean seed treatments that are toxic to bees. The highest concentrations of pesticides in bee pollen, however, were pyrethroids, insecticides typically used to control mosquitoes and other nuisance pests.
“Although crop pollen was only a minor part of what they collected, bees in our study were exposed to a far wider range of chemicals than we expected,” Krupke said.