Scientists Explore Why Bees Are Declining in Virginia

Apr 4, 2017

Several bee species are becoming conservation concerns, with populations declining across the country. Some scientists have been setting bee traps from Charlottesville to northern Virginia to find where they are and why they're dying out.  WMRA’s Miranda Bennett joins the search for one species, the 'rusty patched' bumblebee.

T’ai Roulston had never actually seen one with his own eyes, but the minute he saw the corpse he knew what it was. But he's a scientist, so, just to be sure,

T'AI ROULSTON:  I took it and put it under a microscope and looked and sure enough that's what it was, the rusty patched bumblebee.

When Roulston found this bumblebee in Sky Meadows State Park, east of Winchester, back in 2014, he knew it had been 20 years since this species had been spotted in the region. In other words, for this bee biologist at the University of Virginia, finding this tiny bee was significant.

ROULSTON:  We put out the word that we had found one in the region so it was pretty big.

But the excitement didn't last long. T'ai and his colleagues returned to Sky Meadows the following year, in 2015, but they didn't find any bees. Decades ago the rusty patched were one of the most common bumblebees in Virginia. But then their populations started declining in the 1990s.

ROULSTON: There are various things that stress all the bee populations but why this one as well as several other ones are declining steeply, we're pretty confident it’s disease, and it’s probably from this fungal disease called nosema

Wild bumblebee species across the country are suffering from this disease. But the impact on the rusty patched was particularly severe.  Last month the U.S. Fish and Wildlife Service designated the rusty patched bumblebee an endangered species.

ROULSTON: Why the rusty patched was hit even more than the other declining species, nobody knows. We don't know what other factors made it even more susceptible.

In other words, the fungal disease alone does not explain the decline, nationally, in the numbers of bumblebees, honey bees, butterflies—all the pollinators, in fact.

ROULSTON: Honey bees also suffer quite a lot of diseases, veroa mites and various diseases, but the one thing honey bees have is people working for them.

One of those people is Amanda Welch, a beekeeper in Louisa.

[sound of bees]

AMANDA WELCH: That's a nice hum. They change their pitch when they get pissed.

Miranda: Really? You can tell.

WELCH: That's just a nice calm.  It's a little bit like 'what's that? What's that?'

Unlike bumblebees, honey bees are not native to the U.S. They arrived with the colonists in Jamestown. And now they're shipped around the country to pollinate crops as they flower. But their work for the agriculture system is blamed, in part, for their decline.

WELCH: They started injecting pesticides into the seed that were systemic and get into the entire plant. But there was also trace amounts in the nectar and the pollen and the bees would take that back to the hive and it ends ups building up in the hive. And it also will weaken their immune system so that then when another disease comes in that kills the bees.

It's likely a combination of pesticides, disease, and loss of habitat that's causing the decline in bee species across the state. Both Welch and Roulston stressed that humans do have a role to play in saving these pollinators. Broadly, that might mean changing our agriculture system. But on a smaller scale we can plant more wildflowers.

ROULSTON: With bumblebees we pretty much have to make a safe environment out there for them and hope they find a way to keep themselves going.

While beekeepers like Amanda Welch work to bolster the honeybees, T'ai Roulston keeps studying their wild cousins, ever hopeful that, someday, somewhere, he'll spot a second rusty patched bumblebee.

Learn more about the plight of the rusty patched bumblebee in the documentary film, 'A Ghost in the Making'. It's being screened at the Wild and Scenic film festival tonight (Wednesday, April 5) in Charlottesville and tomorrow (Thursday, April 6) in Harrisonburg.