Up to 13% of U.S. beekeepers are in danger of losing their colonies due to pesticides sprayed to contain the Zika virus, according to a research done by the University of Exeter and the University of California, Berkeley.
The disease, which can cause severe brain defects in unborn children, is spread by mosquitoes, so the insects are being targeted in the south of the country where Zika-carrying mosquito species live.
By comparing data on bee densities with areas at risk from Zika, the researchers calculated the percentage of colonies that could be affected.
"A colony unexpectedly exposed to pesticide spraying for mosquitoes would almost certainly be wiped out," said Lewis Bartlett, of the Centre for Ecology and Conservation on the University of Exeter's Penryn Campus in Cornwall, according to Science Daily.
"Beekeepers in the US move their colonies around to support farmers, so a beekeeper with all their bees in one area at a given time could lose them all."
That is what happened to one of the beekeepers who was caught unaware and lost all her bees, said Bartlett. He added that given all the threats facing bees, even a small additional problem could become a significant issue.
"Many beekeepers live on the breadline, and if something like this changes things, so beekeeping is no longer profitable, there will be huge knock-on effects on farming and food prices,” as bees play a crucial role in agriculture by helping to pollinate crops, he said.
The study found a positive correlation between honeybee colony density and areas with suitable conditions for Zika - raising the risk of bees being harmed by anti-Zika spraying.
These areas include Florida, the Gulf Coast and possibly the California Central Valley.
Some states, such as Florida, have well-established mosquito control programmes and systems to limit the effects on unintended targets such as bees. However, the researchers warn other states are less well prepared to organize measures such as warning beekeepers before spraying, which usually happens in the summer, time in which mosquitoes are traditionally targeted for spraying.
Although the findings do not directly translate to other species, Bartlett said honeybees are resilient compared to most bees, so the situation for other species may be similar or even worse.