Scientists may have found a way to protect bees from pesticides and help mitigate the alarming declines of these vital food crop pollinators around the world, according to a study published in the journal Nature Food.
The US team encapsulated an enzyme that can break down organophosphates – which comprise more than a third of pesticides used – into a pollen-inspired microparticle and found that feeding it to bees protected them from the chemicals’ lethal impact.
“Our design might be able to provide a tool for beekeepers to protect their colonies, notably when visiting areas of intensive agriculture during pollination,” says co-author James Webb from Cornell University, New York.
“In addition, it provides a platform in which researchers may be able to use this feeding vehicle to encapsulate further enzymes that can address other pesticide groups.”
The enzyme they used, amidohydrolase phosphotriesterase (OPT), was previously identified as a potential antidote to pesticide exposure but wasn’t effective when fed to bees as it becomes unstable when exposed to low pH and high temperatures.
Webb and colleagues, including lead author Jing Chen and senior author Minglin Ma, addressed this by microencapsulating the enzyme in calcium carbonate-based microparticles.
The microparticles were designed to protect the enzyme from the acidity of the bee’s digestive tract, carry the enzyme to the bee’s midgut where it can detoxify pesticides as they are released by digested pollen and nectar, and stabilise it for extended shelf life.
Tests confirmed that the microparticles stabilised the enzyme across a range of temperatures and pH values, as well as up to 14 days after manufacturing.
Most importantly, the microparticles – similar in size to pollen grains and thus easily consumed – worked on the bees.
Microcolonies of bumble bees (Bombus impatiens) had a 100% survival rate following pesticide exposure when fed the enzyme with the microparticles, while 0% survived longer than four or five days when fed the enzyme alone or plain sucrose.
The authors say it would likely work for the western honeybee, Apis mellifera, which has a similar gut pH, and could be feasibly used for wild pollinators as well.
The pollen pattie has yet to be tested on whole colonies, but is low-cost and scalable, and the authors are hopeful that its use will also highlight the harm caused by pesticides.
“If this kind of tool was successful in making it to market, it could shed some much-needed light on how bees are able to thrive and cope with other stressors when pesticides are taken out of the equation,” says Webb. “It might provide an inclination for farmers to spray less if they understand the impact they will have on native pollinators.”
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Natalie Parletta is a freelance science writer based in Adelaide and an adjunct senior research fellow with the University of South Australia.
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