New research shows that honeybee death may have as much to do with malnutrition as with pesticide exposure. A recent study from the University of California, San Diego has shown that honeybee death associated with neonicotinoid pesticides is 50 percent more likely when the honeybees have limited access to nutrient sources.
“Intensive agriculture is known to decrease the quality of nutrients, in the form of sugars, available in the nectar and pollen that bees eat,” reports the Independent. “Now scientists have found that when bees eat a low sugar diet, they are 50 percent more likely to die as a result of neonicotinoid exposure.”
The study, which was published in Proceedings of the Royal Society B, is the first to explore the “synergistic” effects of these threats to honeybees, according to Science Daily.
"These findings should cause us to rethink our current pesticide risk assessment procedures, which, based upon our findings, may underestimate the toxic effects of pesticides on bees," Simone Tosi, a postdoctoral researcher in UC San Diego's Division of Biological Sciences and one of the authors of the study, told Science Daily.
To reach these conclusions, researchers raised bee colonies and exposed them to two neonicotinoids – clothianidin and thiamethoxam – as well as limited nutrient sources.
“The combination isn't hypothetical,” reports UPI. “It's the reality in many agricultural areas. Bees' traditional sources of nectar are rare on commercial cropland where pesticides are most common.”
Neonicotinoids have previously been linked to impaired learning and directional ability in honeybees, which could affect the animals' ability to find already limited food sources.
These pesticides were also linked to bee infertility by researchers in Bern, Switzerland last year.
Newsweek reported this month the possibility that the EPA would allow the spraying of thiamethoxam, one of the pesticides tested, on more than 165 million acres of farmland across the country, after Syngenta submitted a proposal to the agency to this effect. The EPA is scheduled to review the safety of thiamethoxam next year.
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