The Quest for the Rusty Patched Bumblebee

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By Claude Christensen

One of the five most common bumblebees twenty years ago, the rusty patched bumblebee was everywhere.

With a black head and a rust colored patch on the back of the abdomen, the rusty patched once thrived in Midwestern prairies, feeding off of an abundant supply of protein-rich pollen and carb-laden nectar. Then it abruptly disappeared.

It took a few years for Dr. Randy Mitchell, University of Akron professor of biology, and others in the Ohio science community to notice the disappearance of the rusty patched. Other bumblebees are encountering difficulties, according to Mitchell, but none like the rusty patched.

Still, Mitchell is worried; he compares the rusty patched to “a canary in a coal mine.” If a once common bumblebee could disappear so suddenly, what does that portend for the rest of the ecosystem and all other pollinators?

Although domesticated honey bees get a lot of attention for their ability to produce large amounts of honey, native wild species like the rusty patched bumblebee are often more important for the health of an ecosystem because they can pollinate a diverse range of plants. Having a diverse portfolio of pollinators ensures an equally diverse range of plants gets pollinated.

Take, for instance, the tomato plant.

“Tomatoes are really weird,” says Dr. Mitchell. They require pollination in order to reproduce, but the typical honey bee is not able to extract pollen from the flower because of the plant’s unique anthers*, the part of the plant’s reproductive apparatus that contains pollen. A tomato plant anther, according to Dr. Mitchell, resembles “a bunch of rocks stuck in a straw.”

Dr. Mitchell identifies a bumblebee temporarily put to sleep with cold compressed air. (Photo: Claude Christensen)

But bumblebees have the tomato plant figured out. By vibrating their wings without flying, bumblebees can “buzz pollinate” tomato plant flowers, causing the pollen to shoot out of the straw-like anthers. “No other bees are either beefy enough or smart enough to figure out this buzz pollination” says Dr. Mitchell.

So bumblebees are an incredibly important element of our ecosystem. But what is causing the decline of common species like the rusty patched?

There is no single answer. It could have suffered from a disease of foreign origin. Harmful systemic insecticides absorbed by plants the bumblebee visits could have killed or handicapped the bee. Rising temperatures could have caused the bumblebee to miss a plant’s window of fertility. Perhaps the devastating fragmentation and destruction of plains and grasslands habitats reached a point of no-return

Dr. Mitchell put it like this: “If I’m sick, everything’ll be okay. If I lose my job, everything’ll (probably) be okay. But if I’m sick and I lose my job, that would be hard to recover from.”

Following this vein of comparison, the rusty patched bumblebee is like a recently-fired victim of lead poisoning whose house also happened to catch fire. The bumblebee has, perhaps, too many obstacles to overcome.

Still, neither Dr. Mitchell nor the scientific community is quite sure why exactly the rusty patched disappeared. It is a mystery he and colleagues, like Ohio State University professor Dr. Karen Goodell, intend to solve as they survey bumblebee populations here in Ohio.

Dr. Mitchell and team preparing to record the density and type of flowers at a site. From left, Jules Christensen, Dr. Randy Mitchell, Paige Reeher (Photo: Claude Christensen)

To conduct a survey, Dr. Mitchell and his team visit likely bee habitat sites and record the number of bumblebees and the plants that the bees seem to be visiting. Armed with long-handled nets and tubes used to contain specimens while they are identified, Mitchell and his team spend hours in the field, even in the humid 90℉ weather of mid-June.

Still, surveys can sometimes be hit or miss. On a recent excursion in Stark county near Hartsville, Dr. Mitchell and his team caught, examined, and released only three bumblebees in four hours. Even with his team, most of whom are college biology students, it would take Dr. Mitchell a long time, too long, to catalogue bumblebees across even just Summit county.

That is why his effort relies heavily on contributions made by members of the general public. By depending on citizen science, the collection of data and collaboration between the general public and professional scientists, Dr. Mitchell is able expand the scope of his survey.

Contributing to Dr. Mitchell’s project is easy. It is as simple as downloading the app iNaturalist on a smartphone and taking a photo.

The app iNaturalist is free to download from both Android and Apple app stores. Anyone can snap a photo of a bumblebee and tag its location. This data is then used by the Ohio Bee Atlas, with which Dr. Mitchell and his team participate. Experts like Dr. Mitchell and his team can identify the photographed bee for whomever takes the photo. What professionals like Dr. Mitchell get out of it is valuable information about where different bumblebees species are.

This is really important. “We don’t have the data,” states Dr. Mitchell. Without the contributions of people who are not necessarily scientists, like the readers of The Devil Strip, the superhuman task of recording bee species across Ohio would be impossible.

So if you have the time today, take out your phone. Download iNaturalist. Go find a bumblebee and help Dr. Mitchell and his team figure out just what happened to the poor rusty patched.

 

For more information about the rusty patched bumblebee and the effort to survey Ohio bumblebee populations, or to nominate a site for a bee survey, visit: u.osu.edu/beelab/ohio-bee-atlas/

Free “Bumble Blitz” Citizen Science Bee Survey: Saturday, July 22, 2017. 11am to 1pm. Letha House Park East, 5745 Richman Road, Spencer, OH 44275. For more information, visit: medinacountyparks.com/index.php/en/programs/special-events

* This article has been updated to correct an erroneous description of the tomato plant’s reproductive organs. Tomato plant pollen is stored in the flower’s anthers, not pistil.

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