We all know that bees are dying at a globally alarming rate, and that our rampant use of pesticides is part of the problem. In a disturbing but wholly unsurprising update this week, scientists have now determined that much of the world’s honey appears to be laced with neonicotinoids, a class of insecticides tied to an array of health and colony development problems in bees.
Neonicotinoids are the most widely used insecticides worldwide, and there’s growing concern about their impact on species we actually like, particularly the wild bees and honeybees that play critical pollinator roles in natural and agricultural ecosystems. A study published last year in Nature Communications linked a drop in wild bee populations in the English countryside to the use of neonicotinoids on nearby crops that the bees forage. Other studies have tied exposure to neonicotinoids to learning deficits in honeybees, and reduced colony growth and queen production in bumblebees.
To get a snapshot of how exposed honeybees are to neonicotinoids globally, a study led by researchers at the University of Neuchâtel in Switzerland measured the concentration of five pesticides—acetamiprid, clothianidin, imidacloprid, thiacloprid, and thiamethoxam—in 198 samples of honey from every continent except Antarctica.
If you’re a honeybee looking for an insecticide-free lunch, the numbers aren’t great. Overall, 75 percent of samples were contaminated with “quantifiable amounts” of at least one pesticide, with North American honey and Asian honey showing the highest levels of contamination (86 and 80 percent of samples from each continent were contaminated with one or more neonicotinoid). European honey trailed closely behind, with 79 percent of samples bearing traces of at least one neonicotinoid, while 57 percent of samples from South America were laced with pesticides. Overall, 45 percent of the honey samples contained two neonicotinoids, while 10 percent contained four to five.
“Our results confirm the exposure of bees to neonicotinoids in their food throughout the world,” the authors write in the study published yesterday in the journal Science.
While the researchers emphasize that concentrations of the neonicotinoids in honey are generally below the threshold for safe human consumption—so you can continue spreading pilfered bee food on your toast worry free—concentrations typically lie within the “bioactive” range that prior research has tied to health problems for honeybees.
The authors added that levels of pesticides in honey from a hive are also “a measure of the contamination in the surrounding landscape,” meaning they’re potentially reflective of what other pollinators are exposed to.
It remains to be seen what, if anything, agricultural industries choose to do with this information. Partial bans on neonicontoids have been implemented—and contested—in the European Union. Recently, France decided to implement a wholesale ban on the pesticides. Neonicontoid bans are controversial among farmers, some of whom contend there is no cost-effective alternative to the chemicals, according to reporting by Phys.org.
Others say that just because bees are exposed to neonicontoids at low levels doesn’t necessarily mean there is a problem. “Yes, there is going to be long-term exposure, potentially, to neonics, but that doesn’t say anything about the risk,” Dalhouise University entomologist Chris Cutler told Nature News.
Clearly, one study isn’t going to settle the debate over whether we should be using these pesticides. But given that bee populations are facing threats on multiple fronts—from climate change, habitat degradation and parasites to name but a few—if humans are inadvertently poisoning the pollinator pantry, we probably ought to think about stopping.
After all, if the bees can’t eat, neither can we.