Wild bees, the original pollinators of the United States’ food supply, are suffering from pesticides just as much, if not more, than their European-descended, commercially bred brethren, according to a new study.
In a paper published Wednesday in Proceedings of the Royal Society B, scientists discovered just how important natural habitat is in protecting native pollinators from the negative affects of both pesticides and supposed “bee-safe” fungicides.
Wild honeybee populations and diversity of species were recorded at 19 apple orchards in various parts of New York in 2011–2012. Scientists collected bees in insect nets for 15-minute periods at each location to obtain standardized samples.
Researchers also gauged the spraying of pesticides and fungicides at each orchard and surveyed the amount of surrounding natural, bee-friendly habitat.
The findings were clear: The more intense the pesticide use in a given orchard, the fewer wild bees and number of species were found. However, more natural habitat around a given orchard blunted the effect of pesticides on wild bee populations.
“The differences we saw from one site to the next were stark,” said study coauthor Bryan Danforth, a Cornell University entomology professor. “We would see 45 different wild bee species in one site, and only five in another.”
Danforth pointed out that other factors—such as the soil quality that ground-dwelling solitary bee species like—could have influenced population numbers from one site to another, and that further testing is needed.
Mia Park, the study’s lead author and a University of North Dakota professor, said the effect of pesticides on wild bees was strongest in the generation that followed pesticide exposure. That suggests pesticides are interfering with wild bee reproduction.
“What we’re trying to find out is the role of the wild bees on pollination outside of the work the honeybee does,” Danforth said.
For the past three years, Danforth has been surveying Cornell University’s 37-acre apple orchard. The site went commercial honeybee–free in 2012, leaving its flowers and future fruits to be pollinated naturally.
“The orchard manager hasn’t noticed any difference in fruit set, and we’ve realized we don’t need honeybees to be trucked in here,” Danforth said.
So, Why Should You Care? About 35 percent of the world’s food production relies on pollination by honeybees, whose numbers have plummeted over the past decade. Beekeepers report 30 to 40 percent losses in bee colonies each year—much higher than what has been considered “sustainable.”
The reason for the honeybee die-offs has been pinned to a range of factors, including neonicotinoid pesticides, fungicides, hive-invading microscopic mites, and even the stresses of truck transport.
“There are a lot of things when it comes to honeybee health that we can’t control,” Danforth said. “If we keep trucking them around the country, the cost of pollinating fields is going to keep going up as the colonies keep declining.”
America needs to “diversify its pollinator portfolio,” he said, and recognize the benefits of wild bees.
Wild bees are better and more efficient pollinators than their foreign brethren, but they don’t get nearly enough credit for their role in pollinating the $30 billion worth of crops annually, Danforth said.
Now, Danforth and his colleagues are looking to put an economic value on wild bees. That study is still in its early stages, but he expects the results to indicate that wild bees are responsible for pollinating at least as much, if not more, than honeybees on the East Coast of the United States.
“What we’re seeing is that native bees are very valuable to New York farms, and what they need is more native habitat,” he said.
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