Cultivating flowering plants for gardens, farms, and landscapes commonly involves the use of herbicides to control weeds. Honeybees are drawn to these flowering areas and play an important role in their success. So what happens when bees encounter weedkillers?
A new study by researchers at Virginia Tech suggests that exposure to glyphosate, one of the world’s most widely used herbicides, disrupts honeybee foraging and threatens the long-term stability of beehives.
In the study, which was recently published in the Journal of Experimental Biology, researchers trained honeybees to forage at artificial feeders - one containing glyphosate and one without it. After just three days, the bees exposed to the weedkiller showed a 13% reduction in foraging.
The researchers also measured changes in honeybee brains. They observed changes that correlated with glyphosate exposure, which could link the neurochemical balance of the bees and foraging effectiveness.
Glyphosate works by blocking an enzyme plants need to survive. Honeybees don’t have that enzyme, which has led to the assumption that the herbicide poses little risk to them.
A 13% reduction in foraging by individual bees might sound small, but researchers say that across a colony the effect could reduce pollination, decrease honey production, and potentially threaten a colony’s long-term survival.
The findings highlight the need to better understand the so-called sublethal effects of pesticides. Protecting pollinators may require more than preventing pesticides from killing bees. It may also require understanding how these chemicals can affect their behavior, brain function, and overall health.
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References:
Researchers show how common herbicide affects honeybee brains and behavior
