Plants and Animals

Bombus auricomus Black and gold bumble bee

Key Characteristics

This is a relatively large species of bumble bee. Both workers and males are approximately 1.7 to 2.0 cm in length, while queens are 2.0 to 2.5 cm in length. Body hair is short and even. Ocelli are low on the face. Characteristics of queens and workers include black face with few scattered yellow hairs; top of head mostly yellow towards the back; thorax is yellow along the anterior and posterior sections, with a distinct black band between the wings;  abdominal segments T2 and T3 are always yellow, and abdominal segment T1 is mostly black with occasional scattered yellow hairs intermixed; and  remaining abdominal segments are always black. Males are similar to queens and workers except they tend to have more interspersed yellow hairs throughout, especially on abdominal segment T1, which can be completely yellow to predominately black. The face of males is mostly yellow, with scattered black hairs (Wallace and Webb 1962, Williams et al. 2014).

Status and Rank

US Status: No Status/Not Listed
State Status: SC - Special Concern (rare or uncertain; not legally protected)
Global Rank: G5 - Secure
State Rank: S2 - Imperiled


CountyNumber of OccurrencesYear Last Observed
Allegan 1 1964
Barry 10 2023
Benzie 1 1954
Berrien 3 2021
Calhoun 1 2021
Cass 3 2021
Clinton 1 1955
Genesee 1 1959
Gratiot 1 2021
Hillsdale 2 1975
Huron 1 1920
Ingham 4 2013
Ionia 5 2021
Jackson 5 2022
Kalamazoo 12 2023
Kent 3 2021
Lenawee 9 2023
Livingston 3 2020
Macomb 1 1937
Monroe 3 1976
Montcalm 3 2022
Muskegon 1 1930
Oceana 1 1934
Ottawa 1 2015
Saginaw 2 2019
Shiawassee 1 1948
St. Joseph 3 2021
Van Buren 1 2014
Washtenaw 5 2020

Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


This species favors prairies and grasslands and is rarely associated with extensive forests. Considered a foraging generalist, this bumble bee will regularly visit floral resources in dunes, marshes, forest edges, farmland, and urban areas. Known foraging resources include bergamots and horse-mints (Monarda spp., clovers (Trifolium spp.), thistles (Cirsium spp.), and vetches (Vicia spp.), among other species (Wood et al. 2019). Nests are usually underground, in old rodent burrows or tufts of grass where there is adequate space for colony development. This species can also occupy agricultural landscapes, however, associated pressures such as ground management and pesticides may restrict populations in these areas. Most Bombus queens overwinter in rotten wood or underground (COSEWIC 2010).

Natural Community Types

For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Management Recommendations

As a foraging generalist, this species needs access to abundant and diverse floral resources. Managing landscapes to maximize season long availability of floral resources is necessary for colony health and reproduction. These actions may include protecting associated natural communities, planting wildflower plots, and incorporating prairie species into habitat management programs. Minimize ground disturbance in occupied habitats to help provide adequate nesting locations. This species may nest within forest edges. Populations found in these landscapes may be particularly sensitive to ground management actions, such as disking, tilling, and herbicide applications. Avoid daytime applications of pesticides (herbicides, insecticides, fungicides). If applications are required, apply in the evening when bumble bee activity is low, or do not apply in occupied habitat.

Active Period

Breeding from fourth week of August to fourth week of September

Flight from first week of June to fourth week of August

Nesting from first week of May to fourth week of June

Survey Methods

Surveys typically involve capturing foraging bumble bees with an aerial net and identifying the individual species (Colla and Packer 2008, Grixti et al. 2009). Observational surveys are also common, and generally require two to three high-quality photos for identification.

Aerial net, visual survey

Survey Period: From first week of May to fourth week of September

Time of Day: Daytime
Cloud Cover: Clear
Air Temperature: Above 60 degrees
Wind: No Wind


Survey References

  • Colla, S.R. and L. Packer. 2008. Evidence for decline in eastern North American bumblebees (Hymenoptera: Apidae), with special focus on Bombus affinis Cresson. Biodiversity and Conservation 17: 1379-91.
  • Grixti, J.C., L.T. Wong, S.A. Cameron and C. Favret. 2009. Decline of bumble bees (Bombus) in the North American Midwest. Biological Conservation 142: 75-84.

Technical References

  • Colla, S.R. and L. Packer. 2008. Evidence for decline in eastern North American bumblebees (Hymenoptera: Apidae), with special focus on Bombus affinis Cresson. Biodiversity and Conservation 17: 1379-91.
  • Colla, S.R., F. Gadallah, L. Richardson, D. Wagner, and L. Gall. 2012. Assessing declines of North American bumble bees (Bombus spp.) using museum specimens. Biodiversity and Conservation 21(14): 3585-3595.
  • COSEWIC. 2010. COSEWIC assessment and status report on the Rusty-patched Bumble Bee Bombus affinis in Canada. Commitee on the Status of Endangered Wildlife in Canada. Ottawa. 34pp.
  • Goulson, D. 2010. bumblebees: behavior, ecology and conservation. Second Edition. Oxford University Press, New York. 317pp.
  • Grixti, J.C., L.T. Wong, S.A. Cameron and C. Favret. 2009. Decline of bumble bees (Bombus) in the North American Midwest. Biological Conservation 142: 75-84.
  • LaBerge, W.E. and Webb, M.C., 1962. The Bumblebees of Nebraska: (Hymenoptera, Apidae, Bombinae). University of Nebraska. College of Agriculture. The Agricultural Experiment Station.
  • Rowe, L.M., D.L. Cuthrell, and H.D. Enander. 2019. Assessing Bumble Bee Diversity, Distribution, and Status for the Michigan Wildlife Action Plan. Michigan Natural Features Inventory, Report Number 2019-33, Lansing, USA.
  • Williams, P.H., R.W. Thorp, L.L. Richardson, and S.R. Colla. 2014. Bumble bees of North America: an identification guide. Princeton University Press.
  • Wood, T. J., J. Gibbs, K.K. Graham, and R. Isaacs. 2019. Narrow pollen diets are associated with declining Midwestern bumble bee species. Ecology, 100(6), e02697.