Rare find of endangered bee’s nest has researchers taking note in Iowa City
One day in early August, Michelle Wiegand was doing yard work at her Iowa City house.
While moving old flagstone rocks, taking out invasive plants and landscaping a creek bed, a familiar buzzing sound stopped Wiegand in her tracks.
Slowing down to observe what was flying around her, Wiegand saw the unique markings of the rusty patched bumblebee before it disappeared into a hole in the ground.
“It was really exciting,” said Wiegand, an education specialist with Johnson County Conservation. “Once I saw that brown patch on its back, it gave it away.”
The rusty patched bumblebee — distinguished by a patch of rusty-orange hair on their abdomen and a fuzzy patch of black on their upper back — has been listed as a federally endangered species since 2017.
To verify her suspicion, Wiegand posted a photo of the bumblebee on iNaturalist, an online platform that connects people to nature by sharing sightings of biodiversity and different species.
Wiegand’s post was flooded with responses from other conservationists and researchers, confirming that it was a rusty patched bumblebee.
Amy Toth, a professor and chair of the graduate program in ecology and evolutionary biology at Iowa State University, said the sighting is noteworthy. Rusty patched bumblebee numbers have declined by 80 percent.
“It used to be common across the northeastern part of the U.S. and Canada,” Toth said. But “its range has been dramatically reduced, so now it’s only really found in just a few states and not in Canada anymore.”
Kyle Price, a field biologist with Environment Solutions & Innovations — an environmental consulting company headquartered in Ohio — visited Wiegand’s property in Iowa City to study the bees in September.
Wiegand’s find was more than a single bumblebee. Price suspected there was a nest underground.
With his colleague Robert Jean — an entomologist with Environment Solutions & Innovations — Price used an endoscopic camera attached to a thick wire to look deep into the hole the bumblebees were observed flying into and out of.
Price said it was important that his team conduct their excavation work in October, so the nest would no longer be active. He said rusty patched bumblebees have a yearlong life span. By October, the queen has hibernated for the winter, and the other bees have died.
The excavation process took about five and a half hours from start to finish, Wiegand said. Price and Jean followed six rodent tunnels underground on the property before finding the bumblebees’ nest, which was more than five feet from the entrance Wiegand initially spotted.
He said the nest likely housed about 150 bumblebees, which is on the smaller side for a nest.
It’s the first rusty patched bumblebee nest found in Iowa since at least 2017.
“Since the species has been listed [as an endangered species] there's only been fewer than 15 nests that have been found for the species since listing altogether,” Price said. “But even prior to the species decline, there was very little information on the nesting habits of the species.”
Why are the bees endangered?
Both Toth and Price said many factors are likely contributing to the rusty patched bumblebee’s decline in North America. Some possible reasons include loss of habitat and variety of flowers on which to feed; diseases spread by commercially raised and exotic bees; and the use of pesticides.
Toth said other species of pollinators are declining as well. She said there are about 15 different bumblebee species in Iowa and over 300 different bee species overall.
Toth and her team at Iowa State have been studying the rusty patched bumblebee actively for three years — work that was detailed by The Gazette in a series about endangered species last year. In those three years, Toth said the nest found on Wiegand’s property is the first nest she’s heard being found in the state.
While Wiegand’s sighting — and the discovery of the nest — is a positive sign, Toth said surveys of the species’ population this year were “much worse” than previous years.
“Although I'm hopeful, the trends are not necessarily positive in what we're seeing in our survey work over the past three years,” Toth said. “What I'm more hopeful about is that people are aware of these bees, in a way that they haven't been in the past.”
Toth said it’s lucky the nest was found by someone who was informed about the bumblebee.
“It technically would have been a federal offense to kill those bees, and if someone found out about it, they could be fined,” Toth said.
Building awareness
Toth, who’s studied bees for 20 years, said she has started seeing an increase in awareness around protecting bees over the past few years.
“When a species becomes federally listed as endangered, it really raises awareness in important ways,” Toth said. “What I'd like people to understand is that the rusty patched bumblebee is only one of many, many species that are disappearing, and so they've become a poster child for conservation.”
Toth said one way the public can spread awareness about the species is by sharing possible sightings to the Bumble Bee Atlas at bumblebeeatlas.org. The website helps track species population. Price said another good way to track sightings is by using iNaturalist, or similar platforms.
Similarly, Price said when the public has more knowledge about a species — especially when it is endangered — it helps researchers study it further.
“Public awareness would be just a great contributing factor,” he said. “Having a few people who know a species and know how to identify it is great, but having an army of folks who can identify this be would allow a lot better opportunity to get a full documentation of its range.”
