The world’s bees are in a bad way. Among the numerous stresses believed to be damaging the population numbers of these extremely helpful little amigos, pesticides are a prime suspect. More specifically, mounting evidence is showing the damaging effect of neonicotinoids, a group of synthetic insecticides chemically related to nicotine.
Now, a new study published in the journal Science has revealed 75 percent of honey worldwide is contaminated with neonicotinoid pesticides. Out of 198 honey samples from across the globe, 75 percent contained a single type of neonicotinoid, 45 percent contained two or more, and 10 percent contained four or five.
The concentrations of neonicotinoids found in the honey are not high enough to harm human health and fall within the amount authorized for human consumption. The levels also aren't great enough to kill the bees. However, a third of the honey samples contained enough pesticide to affect insect health and bee brain function, hindering the bees' ability to forage and pollinate.
“The actual level of exposure can be substantially higher, as the honey samples analyzed in this study represents an average of nectar collection over time and space,” Professor Felix Wäckers, a plant-insect interaction expert at Lancaster University, said in a statement commenting on the research. “Peak contamination levels as experienced by insects collecting from treated crops will be (substantially) underestimated by the method used.”
“This study provides further evidence linking neonicotinoid exposure to the dramatic global decline of wild bees, butterflies, and insects in general.”
Earlier this year, scientists carried out the most comprehensive study to date looking at the effect of neonicotinoids on real-world bee populations, concluding that they are harmful to both wild bees and honeybees in most (but not all) of the studied scenarios.
There have been calls to ban the use of neonicotinoids, most vocally from the European Union. However, the issue of banning or restricting their use remains extremely complex and controversial, both politically and scientifically.
“Clearly, the use of neonicotinoids need to be controlled,” said Dr Chris Connolly, a neurobiologist at the University of Dundee, who wrote a commentary article to accompany the study.
"It is time that these chemicals are heavily restricted for use. In this way, their impact on the environment can be limited and their efficacy against pests preserved for when there is no other alternative option.”
Professor Dave Goulson, a bumblebee ecologist at the University of Sussex, told IFLScience in June 2017: "It is messy and complicated in the real world. It's reached a point where it's getting silly to deny that there is a link between these pesticides and harm to bees. There’s so much evidence now.”