Endangered Species
Midwest Region



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Rusty Patched Bumble Bee


Below is a chronological list of previous Federal Register publications, with associated information materials, and other actions pertaining to the Endangered Species Act status of the rusty patched bumble bee.


Final Rule to List as Endangered

Just 20 years ago, the rusty patched bumble bee was a common sight, so ordinary that it went almost unnoticed as it moved from flower to flower, collecting nectar and pollen. But it's now balancing precariously on the brink of extinction and has become the first-ever bumble bee in the United States -- and the first bee of any kind in the contiguous 48 states -- to be declared endangered.


The endangered designation means that the rusty patched bumble bee is in danger of becoming extinct throughout all or a portion of its range. Service Midwest Regional Director Tom Melius said, “Our top priority is to act quickly to prevent extinction of the rusty patched bumble bee. Listing the bee as endangered will help us mobilize partners and focus resources on finding ways right now to stop the decline.”


Once common and abundant across 28 states from Connecticut to South Dakota, the District of Columbia and two Canadian provinces, the rusty patched bumble bee has experienced a swift and dramatic decline since the late 1990s. Abundance of the rusty patched bumble bee has plummeted, leaving only a few small, scattered populations in 9 states and one province.


News Release


Final Listing Rule: Federal Register January 11, 2017 Adobe PDF Icon


Literature Cited in Final Rule


Questions and Answers


Rusty Patched Bumble Bee (Bombus affinis) Species Status Assessment Adobe PDF Icon (June 2016)


Fact Sheet


Proposal to List as Endangered - Sept. 22, 2016

The U.S. Fish and Wildlife Service proposed listing the rusty patched bumble bee as endangered under the Endangered Species Act, citing a steep decline in the species’ numbers throughout its range. The rusty patched bumble bee, once widespread, is now found in scattered, small populations in 12 states and one Canadian province. Twenty years ago, the rusty patched bumble bee was an abundant native pollinator found across 28 states from Connecticut to South Dakota and north into two provinces in Canada. Today, we find it only in a few locations in Illinois, Indiana, Iowa, Maine, Maryland, Massachusetts, Minnesota, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, Wisconsin – and Ontario, Canada. Abundance and distribution of rusty patched bumble bee populations have declined by an estimated 91 percent since the mid to late 1990s.


Threats to the rusty patched bumble bee include disease (for example, from infected commercial honeybee colonies), exposure to pesticides, habitat loss, the effects of climate change, the effects of extremely small populations, and a combination of these factors.


Bumble bees such as the rusty patched are important pollinators of plants and wildflowers that provide food and habitat for other wildlife. They are also the chief pollinator of many economically important crops. Bumble bees are able to fly in cooler temperatures and lower light levels than many other bees, such as honey bees, making them excellent pollinators for crops like tomatoes, peppers and cranberries. Even where crops can be self-pollinated, the plant produces more and bigger fruits when pollinated by bumble bees.


News Release


Federal Register: Proposal to List as Endangered Adobe PDF Icon


Questions and Answers


Rusty Patched Bumble Bee (Bombus affinis) Species Status Assessment Adobe PDF Icon (June 2016)


Fact Sheet


Current Range: IL, IN, IA, ME, MD, MA, MN, NC, OH, PA, TN, VA, WI and Ontario, Canada

Iowa is also included in the current range. Iowa was not included in current range in the SSA, but very recent occurrences have been verified in Iowa.


Substantial 90-Day Finding - Sept. 18, 2015

The rusty patched bumble bee was included in the Service's response to petitions to list, reclassify and designate critical habitat for a number of species. We made a substantial finding for the rusty patched bumble bee and 22 other species and not substantial findings for 2 species. A "Substantial Finding" means that the petition provides enough information to substantiate that listing these species may be warranted.  After the substantial finding, we began a thorough status review of this bumble bee to determine whether to propose listing any of these species under the Endangered Species Act. 


Federal Register Notice: Petition Finding and Initiation of Status Reviews Adobe PDF Icon (Sept. 18, 2015)


Petition from the Xerces Society Adobe PDF Icon


From petition: The rusty patched bumble bee was historically common from the Upper Midwest to the eastern seaboard, but in recent years it has been lost from more than three quarters of its historic range and its relative abundance has declined by ninety-five percent.


Occasionally nests of the rusty patched bumble bee have been observed above ground. However, nests are usually one to four feet below ground in abandoned rodent nests or other cavities. This species has been observed or collected from woodlands, marshes, agricultural landscapes, and, more recently from residential parks and gardens.


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Midwest Endangered Species


Last updated: March 12, 2018