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Going through a "rusty" patch: The plight of the rusty patched bumblebee

The classic buzz of the bumblebee is one of the signature sounds of the outdoors. These cute, fuzzy insects are gentle and unmistakable – and incredibly important to the environment.

Bumblebees are a keystone species in most ecosystems, meaning they’re essential for native wildflower reproduction, creating seeds and fruits that feed wildlife and pollinating many crops. They're typically active from spring through fall, ensuring essential pollination for wildflowers and roughly a third of all U.S. crops. Bumblebees “buzz pollinate,” where they vibrate their bodies to extract pollen from plants, making them some of the most effective pollinators.

But one bumblebee is facing unprecedented challenges. In 2017, the U.S. Fish and Wildlife Service listed the rusty patched bumblebee as federally endangered – the first bumblebee species, and first wild bee, to be listed in the Lower 48 states.

A small bumblebee with a black head, yellow body, and reddish orange patch under its wings, sips nectar from a wild beebalm flower.
Photo courtesy USFWS Midwest Region.

The rusty patched bumblebee – one of about 250 species of bumblebee – was historically distributed broadly across the eastern U.S., Upper Midwest and southern Quebec and Ontario in Canada. However, since 2000, only 13 states and one Canadian province have reported seeing one. The last time it was reported in Michigan was 1999.

Before it was declared endangered, the bee experienced a widespread and steep population decline, plummeting by about 87% in the past two decades. The exact cause is unknown, but it is suspected that a combination of a disease-causing pathogen, exposure to pesticides, habitat loss and degradation, competition and disease introduction from managed and non-native bees, small population genetics and climate change played a role.

Most native bees do not behave like European honeybees, which is a bee most people are familiar with. Instead of one large superorganism (a collection of many individuals that function as one whole) with tens of thousands of bees, most native bees live either in small underground colonies or are entirely solitary. Bumblebees in particular like to repurpose old rodent dens into their nests.

Rusty patched bumblebees live in underground colonies, made up of the offspring of one queen and one male, and can include more than one thousand worker bees. The workers protect the colony, forage for nectar and pollen and care for young. When a young queen emerges after winter and searches for a place to establish her own nest, it is essential that she find a place with ample flower and nectar sources. In these early stages, she must not only tend to her new colony, but also forage for food until the workers have hatched. All rusty patched bumblebees have entirely black heads, but only workers and males have a rusty reddish patch located in the center of their back, which is where they get their name.

The U.S. Fish and Wildlife Service finalized their recovery plan for the rusty patched bumblebee in 2021. This work includes things like surveys and monitoring, conservation planning, research, habitat management and enhancement, and outreach.

Restoring species is a group effort, and partners from conservation organizations, agencies, local communities and individuals can help.

Whether you live in the country, the city or anywhere between, you can learn more about this bee and provide flowers for pollen and nectar. Here are a few things you can do right now to help this important and interesting insect:

  • Get involved in your local conservation district and volunteer for community science opportunities. If you happen to spot a rusty patched bumblebee, report it! You can help map current populations.
  • Plant native food sources for bees and other pollinators like flowering trees, goldenrod, blueberry bushes, spotted Joe-pye weed and bee balm. Planting a variety that bloom from early spring through fall provides a food source for bees in their active season.
  • Avoid pesticides; use them only when necessary and only use as directed.
  • Leave your garden alone in the fall and spring – many insects, including the rusty patched bumblebee, overwinter in plant matter. Leave bare patches of earth, don’t rake leaves or trim back pithy-stemmed plants. You can also add a bee hotel to your yard.

A person in a beekeeping veil and gloves examines a beehive frame covered in bees.

Emma Kukuk (they/them/theirs, she/her/hers) is DNR communications representative, a beekeeper and certified MSU Pollinator Champion. They love talking about all kinds of bees (not just their honeybees!) and the importance of pollinators.