Yellow bumble bees are a long-tongued bee species (Colla et al. 2011). Due to this, they prefer different flowers as nectar sources than short-tongued bee species, such as red clover and Delphinium (Schweitzer et al. 2012).
Yellow bumble bees appears to be persisting in New York City and Long Island and a couple of disjunct populations in upstate New York (Richardson 2013 and Yanega 2013). There is evidence of a rapid, recent decline of this species in New York (Richardson 2013 and Yanega 2013). In addition, this subgenus (Thoracobombus) has been shown to be significantly more infected by the pathogen Nosema bombi than bumble bees of other subgenera (Cameron et al. 2011).
Species in the subgenus Thoracobombus have declined 99-100% in most of the Northeast (Schweitzer and Sears 2013). There is evidence of a sharp decline in the statewide population since the 1990s (Richardson 2013 and Yanega 2013).
Yellow bumble bees have declined in New York when comparing known post-2000 records to the number of all records pre-2000 based on presence of B. fervidus in proportion to the bumble bee populations in those years as a whole (data from Richardson 2013 and Yanega 2013). While the short-term trend indicates a rapid decline statewide, it has been declining more gradually statewide over the long term, presumably due to other significant threats prior to exotic pathogens in more recent years.
The primary threat to species in the subgenus Thracobombus leading to their rapid, recent decline has been attributed to exotic pathogens. Cameron et al. (2011) showed a higher proportion of Thoracobombus individuals infected by the pathogen Nosema bombi than other bumble bees with stable global populations. In addition, habitat loss, insecticides, and urbanization are known long-term threats for many bumble bees (Schweitzer et al. 2012).
Any efforts to protect wild bumble bee populations from pathogen exposure would benefit yellow bumble bees. Suggested actions would include using mesh to prevent escape of bees from commercial breeding greenhouses, proper disposal of commercial bees, sanitation in greenhouses, and development of molecular screening. Tight restrictions on importing bumble bees and elimination of parasites from commercial populations has been suggested as ideal (Meeus et al. 2011, Schweitzer et al. 2012).
Limiting exposure of yellow bumble bee to insecticides would also benefit them. Suggested actions include avoidance of application to flowers that bumble bees are attracted to and application of solutions or soluble powders (rather than dusts or wettable powders) to the ground in calm wind and warmer tempertures during periods of dewless nights to minimize the impact to resident bumble bee populations (Schweitzer et al. 2012). Organic farming has also been suggested to benefit bumble bees.
Ensuring habitat resources for foraging, nesting, and overwintering will also benefit B. fervidus. Habitats for these needs should be within close proximity to each other and without road or railroads between them, which may be barriers to dispersal. Suggested actions for habitat managment should include ensuring nectar availability throughout the spring and summer by improving flower abundance and species richness and species with overlapping blooms. Select food plants for B. fervidus include vetches, clovers, thistles, honeysuckles, bee balms, Penstemon, and Lythrum (Colla et al. 2011). If mowing of fields occurs, summer is the best time and mower blades should be raised to avoid ground nests. Staggering cutting times in different field areas will ensure nectaring sources are always available. Increasing available nesting habitat may be accomplished by reducing tillage in fields, leaving unplowed strips vegetated, or even providing artificial nesting boxes. Managing for rodents and ground-nesting birds should also benefit bumble bees (Schweitzer et al. 2012).
Further research is needed to determine more information on habitat requirements, threats, climate change effects, and insecticide effects for yellow bumble bee.
Bumble bees are generalist foragers and need nesting habitat in the spring, flowers for adult and larval nutrition throughout the spring and summer, and sites for queens to overwinter. This bumble bee nests above ground and underground (Colla et al. 2011). Such species often use long grass or hay stacks above ground or abandoned rodent nests underground in south facing exposures. Foraging habitat should include flower abundance and species richness with overlapping blooms to ensure nectar availability throughout the growing season (Schweitzer et al. 2012). Select food plants for B. fervidus include vetches, clovers, honeysuckles, thistles, bee balms, Penstemon, and Lythrum (Colla et al. 2011). Suitable sites for bumble bees to overwinter may include rotting logs, mulch, or loose soil (Schweitzer et al. 2012).
The yellow bumble bee has suffered rapid, recent declines in New York but was once widespread statewide (Richardson 2013 and Yanega 2013). Its decline has been attributed mainly to exotic pathogens and insecticide use, but it also faces other threats (Schweitzer et al. 2012, Cameron et al. 2011). More inventories are needed to determine the full extent of its statewide range, but this species appears to be persisting in New York City and Long Island and a couple of disjunct populations in upstate New York (Richardson 2013 and Yanega 2013).
The yellow bumble bee range includes the Canadian maritimes west to southern British Columbia and in the northeastern U.S. south to Georgia and to the west coast (NatureServe 2015).
Yellow bumble bee queens and workers have black faces and yellow hair on the thorax with a black band between the wing bases. Abdominal segments one through four are yellow and segments five and six are black. Males have similar coloration to females, with black hair on the last two abdominal segments (Colla et al. 2011).
Bumble bee queens hibernate over the winter, emerge in the spring, locate a nest site, and rear young (workers, males, and new queens). After new queens and males mate, all males, workers, and old queens die by the beginning of winter and new queens settle into sites to overwinter (Schweitzer et al. 2012).
The time of year you would expect to find Yellow Bumble Bee active and reproducing in New York.
Yellow Bumble Bee
Bombus fervidus (Fabricius, 1798)
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Colla, S., L. Richardson, and P. Williams. 2011. Bumble bees of the eastern United States.
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NatureServe. 2015. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer.
New York Natural Heritage Program. 2019. New York Natural Heritage Program Databases. Albany, NY.
Richardson, L. 2013. Compilation of specimen records for Bombus species of North America from the American Museum of Natural History, Harvard Museum of Comparative Zoology, among several other museums. Unpublished data.
Schweitzer, D. and N. Sears. May 1, 2013. Bumble bee ranking guidelines. NatureServe, Arlington, VA.
Schweitzer, D.F., N.A. Capuano, B.E. Young and S.R. Colla. 2012. Conservation and management of North American bumble bees. NatureServe, Arlington, Virginia, and USDA Forest Service, Washington, D.C. 17 pp.
Yanega, D. 2013. Compilation of specimen records for Bombus species of North America from the University of California Riverside Entomology Research Museum, the Essig Museum of Entomology, University of California Berkeley, the Natural History Museum of Los Angeles County and the California State Collection of Arthropods. Unpublished data.
This guide was authored by: Erin L. White
Information for this guide was last updated on: March 27, 2015
Please cite this page as:
New York Natural Heritage Program. 2019. Online Conservation Guide for Bombus fervidus. Available from: https://guides.nynhp.org/yellow-bumble-bee/. Accessed July 21, 2019.