Neonicotinoids, the insecticides linked to colony collapse disorder, the condition plaguing millions of bees worldwide, has now also been linked to another problem for these critical pollinators--reducing sperm count in male bees by nearly 40 percent, according to new research.
The research, out of the University of Bern, Switzerland, published in the journal Proceedings of the Royal Society B, is the first to link neonicotinoids, the most widely use class of insecticides in the world, with bee infertility.
According to the researchers, the findings may help to explain the rapid decline in bee populations in recent years.
“This could have severe consequences for colony fitness, as well as reduce overall genetic variation within honeybee populations,” the scientists wrote.
Honeybees are responsible for pollinating a startling amount of food-bearing crops—about one-third of all food is the result of bee pollination.
In 2013, the EU imposed a temporary ban on neonicotinoids because of the strong links between the pesticide and decreasing bee populations. Use of neonics on crops have been connected to a decrease in bumblebee queens and reduced reproduction abilities of queen honeybees.
“This study is important, as failures in honeybee queen mating is reported to be a growing problem for beekeepers,” Christopher Connolly of the University of Dundee and not part of the research team, told the Guardian.
“Importantly, this study demonstrates the complexity of the possible consequences from chronic exposure to pesticides and these are not assessed during safety testing.”
Chemical manufacturers of neonicotinoids including Syngenta and Bayer, have long refuted the claims that the insecticides are the leading cause of colony collapse disorder, despite mounting evidence to the contrary.
The researchers also noted that exposure to neonicotinoids reduce the lifespan of drone bees by as much as one-third.
“For the first time, we have demonstrated that frequently employed neonicotinoid insecticides can elicit important lethal and sub-lethal effects on non-target, beneficial male insects,” the researchers wrote, “this may have broad population-level implications.”
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Honeybees image via Shutterstock