This may help explain alarming bee population declines.
A commonly used pesticide may be contributing to dwindling honey bee populations across Europe and North America. According to the results of an experimental study, published in Proceedings of the Royal Society B, insecticides, called neonicotinoids, act as contraceptives, reducing the sperm counts of male drone honeybees.
Neonicotinoids were introduced in the late 1980s and are still widely used in the US, while the European Commission is currently reviewing a temporary ban imposed on the pesticides in 2013.
When sperm output of drones that consumed insecticide-treated pollen were compared under the microscope to those that were not exposed to the chemicals, a clear difference was observed. Bees with neonicotinoids in their food produced on average 1.2 million sperm, which is nearly half as many as the pesticide-exposed bees produced, with an average count of 1.98 million sperm.
SEE ALSO: A Beekeeper has Trained Bees to Make Honey from Cannabis Resin
Though it is still unknown whether that reduced sperm count is sufficient to successfully reproduce with the queen, another study published earlier this year in the journal PLOS ONE linked dying honeybee colonies with failures of queens, which in turn was linked to the drones’ dead sperm.
Lars Straub, the lead author of the new study from the University of Bern, tells New Scientist: “The presence of these chemicals could be one reason behind the struggling bee numbers we’ve seen over the past 15 years in the northern hemisphere.”
He adds, “We can’t be sure though yet because of the sheer number of different factors that affect bee populations – it’s unlikely just the pesticides at work in the wild.”
You might also like: New Study Finds a Banned Pesticide Affects Learning Abilities in Honeybees but Not Bumblebees
Facebook comments