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Bee-laboring the Point: Berkeley Researchers and Volunteers Track Native Pollinators

September 1, 2017
by Aubrielle Hvolboll

Halting mid-sentence, UC Berkeley entomologist Gordon Frankie swings a net towards a flowering beardtongue plant. He reaches into the net and pulls out a wool-carder bee. Holding it between three fingers, he offers it to the volunteers of the Sonoma Bee Count. “Do you see the horns on the tip of the abdomen? That’s clearly a male. Who wants to hold it?” All four volunteers bravely step forward to take it (male bees are unable to sting). “We were the first group to record this guy in California about six years ago,” says Frankie.

The initiative’s citizen scientists at work / Aubrielle Hvolboll
The wool-carder (Anthidium manicatum) and other California bee species have been collected, counted, and identified—in an effort to better understand their contribution to the enviroment—thanks to the work of the UC Berkeley Urban Bee Lab and their citizen-science initiative, the Sonoma Bee Count.

This particular species, Frankie tells us, gets its name from its tendency to scrape fibers from the leaves of lamb’s ear plants. It’s one of more than 1,600 species found in California’s vastly biodiverse landscape, home to nearly half of the 4,000 bee species found in the United States. So far, the Sonoma Bee Count has identified more than 70 species in the agricultural region of Sonoma, a higher number than Bee Lab scientists expected to find in an urban environment.

After they’ve been caught, all bees are tucked into a jar of ethyl alcohol. You can guess what happens next. “Anyone else want to hold him before he goes into the deep six?” asks Frankie before putting the bee into its kill jar. The last flower the pollinator had visited is picked and stored with it. This will later be pinned and identified by the volunteers and preserved at UC Berkeley’s Essig Museum of Entomology. Researchers insist that this is in no way harming the population as a whole—there are many thousands of bees buzzing around the urban-garden oasis.

Bees captured using active trapping methods are laid to rest with the last flower they pollinated. / Aubrielle Hvolboll

The team of researchers at the Bee Lab is looking to document the number of species found in Sonoma and track their populations over a 10-year period. Each year, they return to the same three locations to collect bee specimens with the help of around a dozen local Sonoma volunteers. The study was originally proposed by local beekeeper Shelley Arrowsmith, to better understand what native bees could be found in her backyard. Unlike the honey bees that she keeps, California native bees are abundant locally, and come in all shapes, sizes, habitats, and behavioral patterns.

Long-term studies of California bees are largely nonexistent, so the work of the Bee Lab is key to uncovering how these many native pollinators can supplement pollination from the European honeybee, which is important to maintaining biodiversity. With Sonoma in the agricultural capital of the United States, projects like the Sonoma Bee Count are vital to gaining knowledge of how California’s native pollinators can be preserved in urban and agricultural environments.

Many native bees do not have their own common names, making it more difficult to communicate to the public about local bees. The Bee Lab has worked to change that by giving common names to species, like the Agapostemon texanus which they’ve named the “ultra-green sweat bee,” as it’s known for its metallic green body and varied taste for flowering plants.

Dr. Gordon Frankie in the field with Sonoma Bee Count volunteers / Aubrielle Hvolboll
Walking around suburban Sonoma with Frankie’s group is like walking on a new planet with alien guides. The plants that pollinators visit, the subtle differences in species, their habits and patterns, all quickly become recognizable to the volunteers. Similar to bird watchers who develop “bird eyes,” bee enthusiasts develop “bee eyes.”

The Bee Count’s volunteers employ two tricks to capture native bees: aerial netting and pan traps. Each comes with its own set of advantages and disadvantages. Pan traps, a passive form of capture, trap bees that are often no bigger than a grain of rice and are easily mistaken for flies. Active trapping methods, like aerial netting, let researchers record which flower the bee was visiting when it was caught.

The participants must be wary of their own biases to conduct accurate research. Are the bowls in the sun or in the shade? How many were used, and how far apart were they placed? Each variable is a bias and can skew the data, according to Frankie, so precise documentation is key.

The team of volunteers separate into three groups and lay claim to different collection sites: Gundlach Bundschu Winery, Nathenson Creek, and the location where they had all initially gathered, Sonoma Garden Park. Frankie’s group visits the suburban area surrounding Nathenson Creek.

Aubrielle Hvolboll
Sonoma Bee Count’s volunteers are almost as diverse as the bees in the area: Sage is a kidney-transplant social worker, David is a winemaker, Rita is a teacher, Katy writes novels. This sort of range is common among groups of citizen scientists, as no experience is necessary.

Hopping over a fence to assess a particularly active flowering tree, volunteer Rita LeRoy and Frankie discuss their plan of action if they are called out for trespassing. He suggests mentioning that they are conducting research for UC Berkeley, as that generally elicits approval from wary homeowners.

“This is a people, flower, bee thing,” says Frankie, meaning it takes each of the three for this study to work, and, more generally, to keep bees in urban environments. One Sonoma couple near a test site was so taken by the Bee Count that they decided to uproot their front lawn and replace it with drought-resistant plants that attract native bees.

These kinds of small acts, says Frankie, have helped sustained bees even over the five-year drought. Many Sonoma residents continued to water their green spaces even during the drought, providing bees an oasis in cities. Now, walking through a city of blooming bee-attractive plants, the Bee Lab team is optimistic about the future of the area’s native pollinators.

Aubrielle Hvolboll is a CALIFORNIA intern.

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