Bees have been vital partners in human agriculture for centuries thanks to their role as crop pollinators. However pesticides used to kill other species of insects have wreaked havoc on their hives. A recent study published by the Natural Environment Research Council found that pyrethroid pesticides are causing bees to emerge from their larval stage as smaller workers. This makes them less efficient at foraging for nectar and distributing pollen to other plants.

bumblebee, crop, pollinator, pollen, nectar, pesticide harm

The UK has already banned three neonicotinoid pesticides shown to harm bees, and as a result alternative chemicals such as pyrethroids are being used in their stead. These chemicals are synthetic compounds that mimic substances derived from chrysanthemum flowers and work by interfering with the nerve function of insects. A group from the Royal Holloway University of London led by Professor Mark Brown found that bees exposed to the pesticide hatched from their larval stage significantly smaller, and the insects grew less over time than a control group.

“Bumblebees are essential to our food chain so it’s critical we understand how wild bees might be impacted by the chemicals we are putting into the environment. We know we have to protect plants from insect damage but we need to find a balance and ensure we are not harming our bees in the process.” Professor Brown told The Guardian.

The group plans to conduct further studies in the field to understand the full impact of the pesticides on colonies, and they urge other scientists and governments to do the same. The pesticides are legal in the US, but their use is restricted. The EPA’s warnings are primarily aimed at ensuring that the chemical does not enter storm drains or waterways. While the EPA is confident that a mandatory labeling system will be enough to encourage good stewardship, the latest revelations on how the pesticides affect bumblebees may lead the agency to reconsider its evaluations.

+ Royal Holloway University of London

Via The Guardian

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