Species At Risk

Rusty-patched Bumble Bee

(Bombus affinis)


Rusty-patched Bumble Bee
Rusty-patched Bumble Bee occurrences map


The Rusty-patched Bumble Bee is a medium to large bee, ranging from about one to two centimetres long with queens being at the higher end of this range. Like most bumble bees, it is yellow and black, but males and workers have a distinctive rusty-coloured patch on the second segment of the abdomen.

This bumble bee lives on the pollen and nectar of a wide variety of flowering plants.

Action we are taking:


The Rusty-patched Bumble Bee was once widespread and common in eastern North America, found from southern Ontario south to Georgia and west to the Dakotas.

The species has suffered rapid, severe decline throughout its entire range since the 1970s with only a handful of specimens collected in recent years in Ontario. The only sightings of this bee in Canada since 2002 have been at The Pinery Provincial Park on Lake Huron.


This species, like other bumble bees, can be found in open habitat such as mixed farmland, urban settings, savannah, open woods and sand dunes. The most recent sightings have been in oak savannah, which contains both woodland and grassland flora and fauna.


The cause of the decline of the Rusty-patched Bumble Bee is unknown. Suspected causes include pesticide use and the spread of disease from bumble bees used to pollinate greenhouse vegetable crops. Threats to remaining populations include habitat loss and potentially climate change.


The Rusty-patched Bumble Bee and its habitat are protected under Ontario’s Endangered Species Act.

What You Can Do to Help the Rusty-patched Bumble Bee

  • The Ministry of Natural Resources tracks species at risk such as the Rusty-patched Bumble Bee. You can use a handy online form to report your sightings to the Natural Heritage Information Centre. Photographs with specific locations or mapping coordinates are always helpful. nhic.mnr.gov.on.ca
  • Report any illegal activity related to plants and wildlife to 1-877-TIPS-MNR (847-7667).
  • Private land owners have a very important role to play in species recovery. You may be eligible for stewardship programs that support the protection and recovery of species at risk and their habitats.
  • Pollinators, such as bees, are in steep decline across the globe and they play a key role in the survival of many of Ontario’s rare plants. For information on how you can help scientists monitor pollinator populations in Ontario visit: www.seeds.ca/proj/poll.
  • To provide nectar and pollen for bumble bees, plant a variety of native flowering plants in your garden. Bees tend to prefer pink, purple, and yellow flowers and need food from early spring to late fall.
  • Volunteer with your local nature club or provincial park to participate in surveys or stewardship work focused on species at risk.
  • The Carolinian forests of southern Ontario support an amazing diversity of plants and wildlife, including many species at risk. Carolinian Canada is working to help recover species at risk and their habitats. For more information, visit: www.carolinian.org/SpeciesHabitats.htm.

Did you know?

The Rusty-patched Bumble Bee gets nectar from flowers by biting a hole in the outside of it and sucking up the nectar with its tongue. This behaviour, called “nectar-robbing”, leaves marks on the flower than can help researchers detect the bees’ presence in an area.

Did you know?

Bumble bees perform “buzz pollination”, in which the bee grabs the pollen-producing structure of the flower in its jaws and vibrates its wing musculature, causing vibrations that dislodge pollen that would have otherwise remained trapped in the flower. Some plants, including tomatoes, peppers, and cranberries, require buzz pollination.

Did you know?

Bumble bees are different from other bees because they are large, fuzzy and carry pollen in 'pollen baskets' on their hind legs.

Did you know?

While female bumble bees can sting, they are quite docile and will only sting if their colony is disturbed or they are cornered.

The Endangered Species Act

Contact your local ministry office

Often the best source of local information on species at risk is your nearest ministry office. Call with your questions or concerns.