Over the past 20 years, insecticides have become 120 times more toxic to bees

For the study, the researchers combined several publicly available databases, including usage data.

insecticides from the USGS, toxicity data from the Environmental Protection Agency, and USDA Crop Acreage Data.

Based on these data, biologists compiled a map of the annual "toxic load" on honey bees with insecticides that were used between 1997 and 2012.

The study showed that the volume usedinsecticides in most US states declined between 1997 and 2012. At the same time, the “toxic load” on bees increased approximately nine times on average in the USA - the highest growth (121 times) was recorded in the states of Iowa, Illinois, Indiana, Missouri, Minnesota, Ohio, Kentucky, Nebraska and South Dakota.

"This is a dramatic increase in oraltoxic load is associated with the transition to widespread use of neonicotinoid insecticides, which are unusually toxic to bees when ingested."

Maggie Douglas, lead author of the study

Previously, a group of American scientists came to the conclusion that strong electromagnetic fields negatively affect bees - they reduce their learning abilities and make insects aggressive.