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Endangered Species Program
Conserving and restoring threatened and endangered species and their ecosystems
Rusty Patched Bumble Bee
From Final Listing Rule: Federal Register January 11, 2017
The rusty patched bumble bee is a eusocial (highly social) organism forming colonies consisting of a single queen, female workers, and males. Colony sizes of the rusty patched bumble bee are considered large compared to other bumble bees, and healthy colonies may consist of up to 1,000 individual workers in a season (Macfarlane et al. 1994, pp. 3–4). Queens and workers differ slightly in size and coloration; queens are larger than workers (Plath 1922, p. 192, Mitchell 1962, p. 518). All rusty patched bumble bees have entirely black heads, but only workers and males have a rusty reddish patch centrally located on the abdomen.
The rusty patched bumble bee’s annual cycle begins in early spring with colony initiation by solitary queens and progresses with the production of workers throughout the summer and ending with the production of reproductive individuals (males and potential queens) in mid- to late summer and early fall (Macfarlane et al. 1994, p. 4; Colla and Dumesh 2010, p. 45; Plath 1922, p. 192). The males and new queens (gynes, or reproductive females) disperse to mate, and the original founding queen, males, and workers die. The new queens go into diapause (a form of hibernation) over winter. The following spring, the queen, or foundress, searches for suitable nest sites and collects nectar and pollen from flowers to support the production of her eggs, which are fertilized by sperm she has stored since mating the previous fall. She is solely responsible for establishing the colony. As the workers hatch and the colony grows, they assume the responsibility of food collection, colony defense, and care of the young, while the foundress remains within the nest and continues to lay eggs. During later stages of colony development, in mid-July or August to September, the new queens and males hatch from eggs.
The rusty patched bumble bee has been observed and collected in a variety of habitats, including prairies, woodlands, marshes, agricultural landscapes, and residential parks and gardens (Colla and Packer 2008, p. 1381; Colla and Dumesh 2010, p. 46; USFWS rusty patched bumble bee unpublished geodatabase 2016). The species requires areas that support sufficient food (nectar and pollen from diverse and abundant flowers), undisturbed nesting sites in proximity to floral resources, and overwintering sites for hibernating queens (Goulson et al. 2015, p. 2; Potts et al. 2010, p. 349). Rusty patched bumble bees live in temperate climates, and are not likely to survive prolonged periods of high temperatures (over 35 °Celsius (C) (95 °F (F)) (Goulson 2016, pers. comm.).
Bumble bees are generalist foragers, meaning they gather pollen and nectar from a wide variety of flowering plants (Xerces 2013, pp. 27–28). The rusty patched bumble bee is one of the first bumble bees to emerge early in the spring and the last to go into hibernation, so to meet its nutritional needs, the species requires a constant and diverse supply of blooming flowers.
Rusty patched bumble bee nests are typically in abandoned rodent nests or other similar cavities (Plath 1922, pp. 190–191; Macfarlane et al. 1994, p. 4). Little is known about the overwintering habitats of rusty patched bumble bee foundress queens, but other species of Bombus typically form a chamber in soft soil, a few centimeters deep, and sometimes use compost or mole hills to overwinter (Goulson 2010, p. 11).
Prior to the mid- to late 1990s, the rusty patched bumble bee was widely distributed across areas of 31 States/ Provinces: Connecticut, Delaware, District of Columbia, Georgia, Illinois, Indiana, Iowa, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New Hampshire, New Jersey, New York, North Carolina, North Dakota, Ohio, Ontario, Pennsylvania, Quebec, Rhode Island, South Carolina, South Dakota, Tennessee, Vermont, Virginia, West Virginia, and Wisconsin. Since 2000, the rusty patched bumble bee has been reported from 14 States/Provinces: Illinois, Indiana, Iowa, Maine, Maryland, Massachusetts, Minnesota, North Carolina, Ontario, Ohio, Pennsylvania, Tennessee, Virginia, and Wisconsin.
Colla, S.R. and S. Dumesh. 2010. The bumble bees of southern Ontario: Notes on natural history and distribution. Journal of the Ecological Society of Southern Ontario 141:39-68.
Colla, S.R. and L. Packer. 2008. Evidence for decline in eastern North America bumble bees (Hymenoptera: Apidae), with special focus on Bombus affinis Cresson. Biodiversity Conservation 17:1379-1391.
Goulson, D. 2010. Bumble bees: Behaviour, ecology and conservation. Second edition. Oxford University Press. 317 pages.
Goulson, D., E. Nicholls, C. Bouias, E.L. Rotheray. 2015. Bee declines driven by combined stress from parasites, pesticides, and lack of flowers. Science 347: 1255957-1-1255957-9.
Macfarlane, R.P., K.D. Patten, L.A. Royce, B.K.W. Wyatt, and D.F. Mayer. 1994. Management potential of sixteen North American bumble bee species. Melanderia. 50:1-12.
Mitchell, T.B. 1962. Bees of the Eastern United States. Vol. II. North Carolina Agricultural Experiment Station Technical Bulletin 152:1-557.
Plath, O.E. 1922. Notes on the nesting habits of several North American bumble bees. Psyche 29(5-6):189-202.
Potts, S.G., J.C. Biesmeijer, C. Kremen, P. Neumann, O. Schweiger, and W.E. Kunin. 2010. Global pollinator declines: Trends, impacts and drivers. Trends in Ecological Evolution 25:345–353.
Xerces Society for Invertebrate Conservation. 2013. Petition to list the rusty patched bumble bee. 42pp.
Last updated: March 12, 2018