In a recent study, pollen contaminated with insecticides and fungicides poisoned honey bees and weakened the bees' resistance to a deadly parasite. What's more, the poisoned pollen didn't just come from agricultural crops. In fact, many bees collected most of their pollen from wildflowers, as opposed to the fields that farmers pay beekeepers to pollinate.
Previous studies have mostly focused on insecticides, particularly neonicotinoids, as a cause of the widespread death of honey bees (Apis mellifera) due to a mysterious syndrome, known as colony collapse disorder. In December, the European Union will implement a ban on three types of neonicotinoid insecticide, known as clothianidin, imidacloprid and thiametoxam, reported the BBC.
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However, the new study, published in PLOS ONE, suggests that banning neonicotinoids might not be enough to halt the disappearance of the bees. Other insecticides and fungicides harm bees as well.
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Bees brought home 35 types of insecticides and fungicides after foraging in almond, apple, blueberry, cranberry, cucumber, pumpkin, and watermelon fields.
Bees that were exposed to the chemical cocktail didn't necessarily die immediately, but instead became less resistant to a deadly single-celled parasite, called Nosema ceranae. In addition to the agricultural chemicals in pollen, a mite-killing chemical used to control a pest that attacks the bees also made the honeybees more susceptible to Nosema.
The pollen-poisoned bees were working bugs. Farmers pay beekeepers to bring honey bees to their farms, up to $150 for 10 days in an almond orchard, according to the Charlotte Observer. As Nosema and colony collapse disorder wipe out more bees, the cost for honey bees' pollination services increases.
However, much of the pollen the bees brought back to the hives from blueberry, cranberry, cucumber, pumpkin and watermelon fields actually came from wildflowers and weeds growing around the fields. The only crops that actually received the bees' attention were almonds and apples.
Could it be that high-priced honey bees may be getting the credit for work native insects actually do?
The study's authors suggested that honey bees only visited apples and almonds because these crops are Eurasian species that evolved in the presence of honey bees. On the other hand, blueberries, cranberries and pumpkins are from the Western Hemisphere, where native bees and other pollinators historically filled honey bees' jobs.
The effects of agricultural chemicals on native pollinators also may have serious economic consequences for American agriculture, according to a study published in Frontiers in Ecology and the Environment. Habitat loss, disease and invasive species also threaten these native insects.
IMAGE: A honey bee coated in pollen (Thomas Bresson, Wikimedia Commons)