Indiscriminate Cuckoo Bumble Bee - Bombus insularis
For definitions and diagrams of bumble bee morphology please see the Montana State Entomology Collection's Bumble Bee Morphology page
. Medium-sized: queens (no workers) 16-20 mm in length. Hair length medium; outer surface of hind-leg tibia flat, densely hairy, and lacks pollen basket; hair of face black with a dense yellow patch above base of antennae; sides of thorax yellow at front and black on underside and rear; upperside of thorax with black band between the wings extending back between yellow along midline; T1-2 black or mostly so, T3 black or with some yellow along sides but always black along midline, T4-5 extensively yellow at sides; wings light brown. Male 11-16 mm in length; eyes similar in size and shape to eyes of any female bumble bee; antennae medium length, flagellum 3X the length of scape; hair of face black, with any yellow hairs above base of antennae; upperside of head (occiput) yellow or with many yellow hairs intermixed; T4 with many yellow hairs at sides but a distinct black patch along midline; T7 black; hair length of T3 at front and middle longer than hind-leg basitarsus breadth (Colla et al. 2011, Koch et al. 2012, Williams et al. 2014).
Across the range, queens reported April to September, males May to September; no workers (Williams et al 2014). Queens May to August, males July to September in southern Ontario (Colla and Dumesh 2010, Colla et al. 2011); queens March to September, males July to September in Utah (Koch et al. 2012); queens late March to late October, males late April to late September in California (Thorp et al. 1983).
Please see the Montana State Entomology Collection's Key to Female Bumble Bees in Montana
. Females told from other Montana Bombus
by a combination of the outer surface of the the hind-leg tibia convex and hairy, no pollen basket present; top of head (occiput) predominantly of yellow hairs; hairs of face predominantly yellow around antennae bases; S6 with evenly rounded side ridges.
Resident Year Round
Recorded Montana Distribution
Click the map for additional distribution information.
In western North America from Alaska south through the Cascade, Sierra Nevada, and Rocky Mountains west of the Great Plains to southern California, Arizona, and New Mexico, and east across southern Canada to New England and southern Quebec (Colla et al. 2011, Koch et al. 2012, Williams et al. 2014). In Colorado, found at elevations of 1600-4000 m, but mostly between 2400-3000 m (Macior 1974); at least 1600-3000 m elevation in California (Thorp et al. 1983). In Montana, reaches at least 3050 m elevation in the Beartooth Mountains (Bauer 1983). Evidence of declines in parts of its range, possibly because of declines in host bumble bee populations (Colla et al. 2012, Williams et al. 2014).
Found in a wide variety of habitats, including native prairie, sagebrush steppe, montane and subalpine meadows, alpine tundra (Macior 1974, Bauer 1983, Mayer et al. 2000, Wilson et al. 2010, Cook et al. 2011, Miller-Struttmann and Galen 2014).
Does not collect pollen, but feeds on a variety of flowers, including Achillea, Agastache, Agoseris, Anaphalis, Archtostaphylos, Asclepias, Astragalus, Besseya, Cirsium, Corydalis, Chrysothamnus, Dipsacus, Epilobium, Erigeron, Erysimum, Eupatorium, Heliomeris, Iris, Melilotus, Microseris, Oxytropis, Penstemon, Phacelia, Polygonum, Primula, Rhododendron, Ribes, Rhus, Rubus, Sedum, Senecio, Solidago, Taraxacum, Trifolium, and Vaccinium (Macior 1974, Bauer 1983, Thorp et al. 1983, Mayer et al. 2000, Wilson et al. 2010, Miller-Struttmann and Galen 2014, Williams et al. 2014).
A social parasite of other Bombus, including B. appositus, B. fervidus, B. flavifrons, B. nevadensis, B. occidentalis, B. rufocinctus, B. ternarius, and B. terricola (Hobbs 1965a and b, 1966a and b, 1968; Williams et al. 2014). Parasitic queens invade hosts nests, sometimes kill the host queen, and recruit host workers to raise parasite progeny. This is necessary because parasite queens do not gather pollen required to fed their own larvae. Host workers sometimes defend against parasite queens by covering them in honey. As many as 12 parasite eggs are laid per cell; eggs produce only queens and males. Males patrol circuits in search of queens.
- Literature Cited AboveLegend: View Online Publication
- Bauer, P.J. 1983. Bumblebee pollination relationships on the Beartooth Plateau tundra of Southern Montana. American Journal of Botany. 70(1): 134-144.
- Colla, S., L. Richardson, and P. Williams. 2011. Bumble bees of the eastern United States. Washington, DC: USDA Forest Service, Pollinator Partnership. 103 p.
- Colla, S.R., F. Gadallah, L. Richarson, D. Wagner, and L. Gall. 2012. Assessing declines of North American bumble bees (Bombus spp.) using museum specimens. Biodiversity and Conservation 21: 3585-3595.
- Cook, S.P., S.A. Birch, F.W. Merickel, C.C. Lowe, and D. Page-Dumroese. 2011. Bumble bee (Hymenoptera: Apidae) community structure on two sagebrush steppe sites in southern Idaho. Pan-Pacific Entomologist 87(3): 161-171.
- Hobbs, G.A. 1965a. Ecology of species of Bombus Latr. (Hymenoptera: Apidae) in southern Alberta. II. Subgenus Bombus Robt. Canadian Entomologist 97(2): 120-128.
- Hobbs, G.A. 1965b. Ecology of species of Bombus Latr. (Hymenoptera: Apidae) in southern Alberta. III. Subgenus Cullumanobombus Vogt. Canadian Entomologist 97(12): 1293-1302.
- Hobbs, G.A. 1966a. Ecology of species of Bombus Latr. (Hymenoptera: Apidae) in southern Alberta. IV. Subgenus Fervidobombus Skorikov. Canadian Entomologist 98: 33-39.
- Hobbs, G.A. 1966b. Ecology of species of Bombus Latr. (Hymenoptera: Apidae) in southern Alberta. V. Subgenus Subterraneobombus Vogt. Canadian Entomologist 98: 288-294.
- Hobbs, G.A. 1968. Ecology of species of Bombus (Hymenoptera: Apidae) in southern Alberta. VII. Subgenus Bombus. Canadian Entomologist 100(2): 156-164.
- Koch, J., J. Strange, and P. Williams. 2012. Bumble bees of the western United States. Washington, DC: USDA Forest Service, Pollinator Partnership. 143 p.
- Macior, L.M. 1974. Pollination ecology of the Front Range of the Colorado Rocky Mountains. Melanderia 15: 1-59.
- Mayer, D.F., E.R. Miliczky, B.F. Finnigan, and C.A. Johnson. 2000. The bee fauna (Hymenoptera: Apoidea) of southeastern Washington. Journal of the Entomological Society of British Columbia 97: 25-31.
- Miller-Struttmann, N.E. and C. Galen. 2014. High-altitude multi-taskers: bumble bee food plant use broadens along an altitudinal productivity gradient. Oecologia 176:1033-1045.
- Thorp, R.W., D.S. Horning, and L.L. Dunning. 1983. Bumble bees and cuckoo bumble bees of California (Hymenoptera: Apidae). Bulletin of the California Insect Survey 23:1-79.
- Williams, P., R. Thorp, L. Richardson, and S. Colla. 2014. Bumble Bees of North America. Princeton, NJ. Princeton University Press.
- Wilson, J.S., L.E. Wilson, L.D. Loftis, and T. Griswold. 2010. The montane bee fauna of north central Washington, USA, with floral associations. Western North American Naturalist 70(2): 198-207.
- Additional ReferencesLegend: View Online Publication
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- Dolan, A.C., C.M. Delphia, K.M. O'Neill, and M.A. Ivie. 2017. Bumble Bees (Hymenoptera: Apidae) of Montana. Annals of the Entomological Society of America. 110(2): 129-144.
- Kearns, C.A. and J.D. Thomson. 2001. The Natural History of Bumble Bees. Boulder, CO. University Press of Colorado.
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