No junk-food diet: Even in cities, bees find flowers and avoid processed sugars

Date: May 18, 2016

Source: North Carolina State University

New research from North Carolina State University finds that bees in urban areas stick to a flower-nectar diet, steering clear of processed sugars found in soda and other junk food.

"Urban habitats are growing, as is urban beekeeping, and we wanted to see if bee diets in cities are different from those in rural areas," says Clint Penick, a postdoctoral researcher at NC State and lead author of a paper on the study. "For example, we wanted to know if there are even enough flowers in urban areas to support bee populations, or if bees are turning to human sugar sources, like old soda."

To find out, the researchers collected worker honey bees (Apis mellifera) from 39 colonies across rural and urban areas within 30 miles of Raleigh, North Carolina. Twenty-four of the colonies were managed by beekeepers; the remaining 15 colonies were feral.

The researchers then analyzed the carbon isotopes in the bee samples to determine what proportion of their diet came from processed sugars -- like table sugar and corn syrup -- as opposed to flower nectar.

Animals, including bees, incorporate the carbon from food into their bodies. One type of carbon, carbon-13, is associated with grasses such as corn and sugar cane. Researchers can tell how much processed sugar bees consume by measuring each bee's carbon-13 levels. The researchers took a similar approach in a previous study that evaluated the diet of ants in New York City.

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