Dramatically falling bee populations aren’t a sign of the impending apocalypse or even a hive-mind abandoning Earth but the side-effect of neonicotinoid insecticides discovered to be highly toxic to honeybees. Researchers at Purdue University found the insecticides – which are commonly used to coat corn and soybean seeds prior to planing, Science Daily reports – cause tremors, loss of coordination and convulsions, before eventually death, in bees. However, discovering the cause of the decline is only part of the problem: bee populations in the US continue to dive by around a third each year, the Purdue team believes.
The treated seeds themselves aren’t what causes the problem, it’s suggested: instead, it’s how the seeds are planted. Farm machinery used to sew the fields release high concentrations of the insecticides in the waste talc that is exhausted; the clouds are “quite light” and “quite mobile” Christian Krupke, associate professor of entomology and co-author of the Purdue report says, and contain around 700,000 times the dose required to kill a bee.
“This material is so concentrated that even small amounts landing on flowering plants around a field can kill foragers or be transported to the hive in contaminated pollen” Krupke continues. “The fact that these compounds can persist for months or years means that plants growing in these soils can take up these compounds in leaf tissue or pollen.”
Although crops are obviously important, the honeybees do vital work in cross-pollination. In fact, the US Department of Agriculture says they’re worth up to $20bn annually to commercial farming processes. Even reduced amounts of neonicotinoid insecticide dust could still present a problem, with the researchers suggesting the bees exposed, although not killed outright, could be more susceptible to disease and lose their hive honing abilities.