Endangered bumble bees were found in Iowa City. Researches hope to learn from their nest.

The rusty patched bumble bee had only been seen in seven states over the last 10 years. That was until a Johnson County Conservation staff member noticed groups of bees exiting and entering a small hole in an Iowa City yard.

The rusty patched bumble bee has declined in population since the late 1990s and early 2000s. By 2017, the federal government made it an endangered species.

The rusty patched bumble bee used to live in 28 states. This is the first nest found in Iowa since the species was listed as federally endangered, according to Johnson County Conservation officials. Researchers at Iowa State University found the bees in four locations across the state during a survey in 2022.

How was the rusty patched bumble bee discovered in Iowa City?

The staff member believed the bees, which were nesting in their yard, were rusty patched bumble bees. So they took to the internet. The staff member made a post on iNaturalist, an online platform for crowdsourcing species identification, about their theory.

Kyle Price, a scientist from West Virginia who works for Environmental Solutions and Innovations, saw the post and reached out to Johnson County Conservation. Price first visited the nest site in mid-September. He returned the week of Oct. 21 with a colleague to excavate the nest that completed its life cycle.

How was the rusty patched bumble bees' nest excavated?

Excavation of the endangered species' nest took five and a half hours. The rusty patched bumble bee built its nest in old and abandoned rodent holes underground, according to Johnson County Conservation. The nest was found more than 5 feet from the suspected main entrance.

What is being done with the excavated rusty patched bumble bees' nest?

Because so little I know about the rusty patched bumble bee's nest, the one found in Iowa City will be used to research the species. Researchers will extract DNA from the nest to understand the species' population trends. It will also be used to train dogs to find the rusty patched bumble bees' nesting sites in the future.

Two dead queen rusty patched bumble bees were found in the nest. One of them was the founding queen, who started and raised the colony. The other was a gyne, which was a newly-born queen.

"This alone is a great opportunity as collecting genetics and DNA from a queen is extremely rare," Price told the Register in an email."

Scientists will collect "non-lethal generic samples" from male and worker bees during summer surveys, but never attempt to capture or collect DNA from queens, he said. Any negative interaction or harm to a queen could cause localized extinction.

Researchers will analyze the internal nesting materials as well as soil samples. This will help researchers piece together the entire nesting ecology for the species, which currently has very limited data, Price said. Researchers will also look for any pathogens that cause diseases and threaten the rusty patched bumble bee.

What do rusty patched bumble bees look like?

At first glance, a rusty patched bumble bee may be difficult to distinguish. Rusty patched bumble bees' thorax, or the area between the neck and abdomen, is mostly yellow. It also has a black spot or band between the wings that may extend toward the back in a v-shape, according to the U.S. Fish and Wildlife Service.

Male rusty patched bumble bees have an abdominal segment that is yellow, but the second has a patch of "rusty hairs" on the front.

What can be done to help the rusty patched bumble bee populations?

Just like bumble bees, the rusty patched bumble bees are also critical pollinators for food crops and native flowering plants, Michelle Wiegand, a naturalist with Johnson County Conservation, told the Register by email on Thursday.

Because rusty patched bumble bees and most other species of bumble bees nest underground in Iowa, Wiegand asks people to be aware and if a nest is found, leave it until the end of its life cycle.

Rusty patched bumble bees' nests have an annual life cycle and are usually abandoned in the fall.

"I hope this story can encourage more people to react with curiosity rather than an automatic response to kill a nesting population," Wiegand wrote.

Here are other tips from Johnson County Conservation for protecting rusty patched bumble bees and other pollinators:

• Plant native plants with staggered bloom times, bumble bees rely on early spring ephemerals in bloom beginning in April when bees emerge from their overwintering habitat through fall blooms in September.
• Leave fallen leaves for bees and other pollinators. These organisms overwinter in fallen leaf litter or in loose soil protected by fall leaves and brush.
• Eliminate chemical use in your yard. Bees can absorb chemicals through their exoskeletons which is especially problematic because so many bumble bees are nesting under soil, which may have been treated chemically or has run off chemicals from nearby farms or neighboring lawns.
• Engage with community science platforms, like iNaturalist, Bumble Bee Watch, eBird and HerpMapper. These platforms help inform community members who may not be experts and connect them to scientific communities.