There is a general consensus that bees all over the planet have problems. A few years ago, the nests of domestic bees began to experience mass deaths, and anomalies were also found in wild bees. What was not clear is what caused it. Viruses, fungi and pesticides have been highlighted as possible causes, but finding definitive evidence has been difficult to come by.
Now, two new studies published in the journal Science finally provide strong evidence that popular pesticides called neonicotinoids are fatal to the pollinator bees that keep our food production system going.
What are neonicotinoids?
Chemically similar to nicotine and invented in the 1980s, they are the most widely used insecticides on the planet -especially in crops- as they act on the central nervous system of insects.
The definitive evidence has been found not in laboratory experiments, where bees could receive unrealistic doses of pesticides, but in open fields, specifically in regions of Europe and Canada, and the conclusions are bad, very bad.
To measure the potential damage, a team of European researchers established 33 sites with rapeseed crops in Germany, Hungary and the United Kingdom randomly assigned to be treated with one of the two most widely used insecticides worldwide or with no insecticides.
The team examined honey bees – European bee – and two species of wild bees – bumblebees and solitary bees. The results differed between locations and species, but overall it was found that bee hives were less likely to survive the winter, while wild bees reproduced significantly less.
The scientists found that the pesticides did not directly kill the bees but did make them more vulnerable , especially if there were other environmental factors or diseases already affecting the hive.
Another field study by Canadian researchers has also shown these negative effects on bees. The scientists studied honey bees that lived near neonicotinoid-treated corn fields or far away from agricultural fields. The results suggested that the chronically exposed bees had a lower life expectancy and lower hygiene conditions in the hive . In addition, they also discovered that bees collected pollen contaminated with pesticides, but this pollen did not even come from the treated crops themselves.
“This indicates that neonicotinoids, which are soluble in water, spill from agricultural fields into the surrounding environment , where they are absorbed by other plants that are very attractive to bees,” confirms Nadia Tsvetkov, co-author of the work.
“Our results suggest that even if their use was restricted, as in the recent EU moratorium, continued exposure to neonicotinoid residues resulting from their previous widespread use has the potential to negatively impact the persistence of wild bees in landscapes. agricultural, “the study researchers write.
Will this study lead to a blanket ban on these pesticides? The truth is that there is already a temporary ban since 2013. We will see what happens now.
Referencia: Chronic exposure to neonicotinoids reduces honey bee health near corn crops. Science DOI: 10.1126/science.aam7470. Country-specific effects of neonicotinoid pesticides on honey bees and wild bees. Science DOI: 10.1126/science.aaa1190.
