Between the destruction of open spaces and the rise of urban beekeeping, former country bees are finding themselves in the city a lot these days. Fortunately, the change of scenery might not be impacting their diets too much; researchers say that city bees generally stick to drinking flower nectar, even in the presence of spilled soda. Their study was published in the Journal of Urban Ecology.
Clint Penick is a biologist at NC State University. He’s especially interested in learning about how social insects like bees and ants adapt to new surroundings or circumstances. In 2013, Penick and his colleagues collected ants from the parks, sidewalks, and traffic medians of Manhattan to find out what the ants were eating.
The answer, unsurprisingly, was garbage—or, more specifically, the remains of junk food. The half-eaten cheeseburgers of city dwellers are so plentiful and calorie-laden that the ants had turned away from their usual diet of dead bugs.
Would the same be true for urban bees? The researchers decided to find out. They collected honeybees from 39 colonies (24 belonging to beekeepers, and 15 wild) in Raleigh, North Carolina, and the surrounding region. They then tested the bees the same way they’d tested the ants: by looking at stable isotopes in the bugs’ bodies. Everything we eat leaves a chemical signature behind. Foods made from sugarcane and from corn, including corn syrup, have a unique effect on a body’s carbon levels. By looking at a bee’s carbon-13 isotopes, researchers could tell if that bee had been eating people food.
Overall, the bees appeared to be sticking to a fairly natural diet. “Basically, bees are relying on flowers in cities and are not turning to human foods to supplement their diet,” Penick said in a press statement. “This is good news for urban beekeepers. The honey in their hives is mostly coming from flower nectar and not old soda, which is what we originally guessed.”
The researchers note that this study took place in a mid-sized city and not, say, Manhattan, where the ants were tested. “Even the most urban areas of Raleigh have more than 50 percent open green space,” Penick said. “By comparison, the average site in New York City has only 10 percent green space. So more work needs to be done to evaluate bee diets in our largest cities.”