Finding Out More About Native Bees

SRS research forester Henry McNab explains how bees are collected. Photo by Sarah Farmer.
SRS research forester Henry McNab explains how bees are collected. Photo by Sarah Farmer.

When people think about bees, it’s often honeybees that come to mind. Native to Eurasia, honeybees pollinate apple, peach and almond trees, watermelons, cucumbers, and many other food crops. In many areas, beekeepers take to the highway with their colonies, traveling to whatever crop is blooming and in need of pollination. “Honeybees are an agricultural commodity comparable to chickens,” says Sam Droege, a scientist with the U.S. Geolological Survey Patuxent Wildlife Research Center. “They aren’t required for pollination of native plants, but they’re invaluable pollinators of agricultural crops.”

Native bees — all 4,000 species of them — are very different. Except for bumblebees, which are semi-colonial, native bees live alone or in small family groups, possibly exempting them from colony collapse disorder. And while they don’t make honey, native bees pollinate native trees such as tulip poplar and sourwood, as well as many herbaceous plants.

Native bees and wild honeybees are a bit mysterious: nobody really knows if their populations are in decline or not. Droege designed a nationwide survey to collect information on native bees and honeybees from all across the country, and determine whether wild bee populations are healthy or not. A number of U.S. Forest Service Southern Research Station (SRS) Experimental Forests and Laboratories are participating in the study. For more information, read Monday’s article Tracking Bees on Experimental Forests.          

Pollen sticks to bees’ fuzzy hairs: when they fly from plant to plant to feed, bees also shuttle pollen between the plants. Photo by Sam Droege, USGS.
Pollen sticks to bees’ fuzzy hairs: when they fly from plant to plant to feed, bees also shuttle pollen. Photo by Sam Droege, USGS.

“I didn’t realize how easy it would be to take care of the traps,” says Henry McNab, a research forester at Bent Creek Experimental Forest. “It really doesn’t take but 5 minutes every couple of weeks to monitor these traps and cost for supplies is about $20 annually.” The traps are simple plastic cups, painted blues and yellows to attract bees, and filled with non-toxic propylene glycol. “See, all you do is pour the glycol through this little strainer, and then empty the insects into a bag,” says McNab. “I store the bags in the freezer for a few weeks and then mail everything to Droege for identification.”

According to Droege, identification is the bottleneck in the process. “It’s like learning bird calls with a microscope, but there isn’t any singing,” says Droege.

Although it will take many years of collecting data to identify trends in rare species, the survey will be able to identify long-term trends in more common species a bit sooner. “It can take up to 10 years of data collection to get data that’s good enough to identify trends in populations,” says Droege. “After a year, everybody’s like ‘how are the bees doing?’ and we have to say ‘come back in 10 years.’”

Droege designed the survey and leads the project, but because of its ambitious scale, the participation of the experimental forests and other public lands is crucial. The survey also represents an opportunity for the experimental forests to contribute to a nationally relevant study.

“A lot of what we do here at Bent Creek is very regionally focused. Silviculture is constrained by local site conditions,” says McNab. “This project is different. Because the sampling sites are spread across the entire country, we can get a really comprehensive look at how bees are doing. A lot of important projects are not especially interesting, and many interesting projects not very important. Every once in a while, a project like this comes along that is both interesting and important.”

For more information about the project, contact Sam Droege at sdroege@usgs.gov

For more information about the SRS role in the bee monitoring project, contact James M. Guldin at jguldin@fs.fed.us

Access the latest publications by SRS scientists.

 

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