City Bees Skip the Junk Food, Prefer Flowers
A new study examines the impact of urbanization on the diet of bees.
Do bees in urban settings eat differently than their country counterparts? With increased urbanization and fewer places to forage naturally, would the city slickers feast more readily on processed-sugar junk foods than on the nectar of flowers?
Those were the questions underpinning a new study out of North Carolina State University just published in the Journal of Urban Ecology.
To get some answers, N.C. State researchers gathered worker honey bees from colonies in both urban and rural areas within 30 miles of Raleigh, N.C. All told, they collected bees from 39 colonies – 24 run by beekeepers and 15 that were wild.
To gauge how much of the bees' diet came from processed sugars vs. flower nectar, the scientists studied them for their levels of carbon-13, an isotope whose presence in their bodies would indicate how much human food each bee was taking in.
It turned out that the scientists were in for a surprise.
The researchers say they turned up no evidence that urban bees had consumed more processed sugar than their rural counterparts.
"Basically, bees are relying on flowers in cities and are not turning to human foods to supplement their diet," Clint Penick, lead author of the study, said in a statement.
"This is good news for urban beekeepers," he said. "The honey in their hives is mostly coming from flower nectar and not old soda, which is what we originally guessed."
The finding, the research team wrote, "suggests an important role for urban flowers and green spaces in maintaining healthy pollinator populations in cities."
Penick said further study would be needed to test if their results would apply to cities much larger than Raleigh, which is mid-sized, at just under 440,000 residents.
A honey bee pollinates lavender.
The U.S. Geological Survey is posting photos of insects on its
, offering a macro look at this hidden world. First up, this Festive Tiger Beetle (
) was found on top of a butte in Badlands National Park that had ancient windblown sand at its crest. Here, this sand specialist can build its long burrows.
This Agapostemon bee species is one of the most common native bees in the eastern United States. In almost any field there can be hundreds, if not thousands, of these bees visiting a wide variety of blooming plants. One of the largest of the sweat bees, it still goes undetected if you don't get down on your knees, face close, among the flowers. This one was collected at Colorado National Monument, Mesa County, Colo.
This wild bee (
), a female from Grand Tetons National Park, was collected as part of a study of climate change. Most species in this genus are black , but a few, like this one, are as the Latin in name implies, glittering jewels.
This unknown wasp was collected in Cecil County, Md.
This is an unknown species of Robber Fly from Charles County, Md. Robber flies, a very large and widespread type of fly, feed on many different kinds of insects, making them a key player in maintaining the insect balance in different environments.
One species of the rarely seen leafcutting bee, this is
from the sandhills of North Carolina. Leafcutter bees are so called because they cut plant leaves to create the cells in their nests. The bees tend to build their homes in rotted wood or in the strong stems of plants.
is a type of jumping spider. This one was found in Beltsville, Md., but
lives in fields and prairies across North America. It feeds on seasonal plants.
Eggplant Tortoise Beetles like eggplants (go figure), eating holes in the plants' leaves. From the underside, the insects look quite queenly, with their ruffled collars. This one was gathered at the Patuxent Wildlife Research Center, in Anne Arundel County, Md.
The Karner blue butterfly,
Lycaeides melissa samuelis
, is endangered. Karner blue butterflies feed on nectar from many different types of flowers, but their larvae can survive on the leaves of only one specific plant, which has been decimated by habitat loss or change.
Deer flies like this one, despite their groovy eyes, deliver a ferocious bite. And no wonder: when the female bites (males don't bite), she lacerates the skin and when the blood flows, sponges it up with her mouth. There are over 110 species of deer fly.
Centris bees, like this one, make their homes in holes, either in trees or in the ground.
The biggest visual difference between damselflies and dragonflies are their wing positions when resting. Dragonflies hold their wings open, while damselflies close them above their backs. This Ebony Jewelwing Damselfly (
) was found on a Beltsville, Md. stream.