| Scientific Name |
 Click photo to enlarge. Photo by Charles Wilder. |
||||
| Bombus pennsylvanicus (Degeer) - (subgenus: Fervidobombus) - ATBI Database: Specimen Records | |||||
| Common Name | |||||
| Bumble bee | |||||
| Kingdom | Phylum | Class | Order | Family | |
| Animalia | Arthropoda | Insecta | Hymenoptera | Apidae | |
| Animals | Arthropods | Insects | Sawflies, Parasitic wasps, Ants, Wasps, and Bees | Long-tongued bees | |
Bombus pennsylvanicus is also known as Bombus americanorum, the confusion coming from the original description. It is not always clear which species we recognize today was described by which early taxonomist, especially as many early type specimens, those used to describe a new species, have been destroyed or lost. The queens and drones (males) are not produced until all of the eggs that will be workers have been laid, usually late in the season. The drones are often not found visiting flowers until late in the summer, July or August, though this species has some of the earliest drones (Medler and Carney 1963). Bombus pennsylvanicus males will often wait around the entrance to hives for the queens to emerge, competing with each other for access.
SPECIES DESCRIPTION
Physical Description: (Medler and Carney 1963 and Speight 1967) Queen:
22 to 25.5mm in length; abdomen width 10.5 to 11.5mm.
Head entirely black, sometimes with few gray hairs above base of the antennae; back of the thorax
is all yellow towards the head and black toward the abdomen, sometimes with some gray hairs; abdominal segments 1-3 are yellow and segments 4-6 are black.
Worker: 14 to 19mm in length; abdomen width 5.5 to 8.5mm.
Like the queen in appearance.
Male:
18 to 21.5mm in length; abdomen width 8mm.
Face grayish-white and rest of head black with some gray; thorax like females, abdominal segments 1-4 and sometimes
5 are yellow, other segments variable; hard to tell apart from Bombus fervidus.
DISTRIBUTION
Global
Bombus pennsylvanicus ranges from the Quebec to South Dakota, south to Florida, Mexico and possibly Central America (Kearns and Thomson 2001). The genus Bombus is found on all continents except Australia, with the highest diversity found in central Asia. There are about 250 described species world-wide. Members of this genus are especially important for the fertilization of some species of clovers and other plants due to their unusually long tongues.North America / Regional
Bombus pennsylvanicus is widely found throughout eastern Tennessee. Recorded flying in Tennessee from the beginning of April through the end of September (Speight 1967).Park
 Click map for current locations. |
Bombus pennsylvanicus is recorded from Cades Cove, Tremont, Sugarlands, and the Alum Cave Trail. Park records start the third week in May and continue through the middle of August. |
NATURAL HISTORY
Habitat
Bumble bees typically choose nest sites below ground in preexisting holes, or at ground level in grass tussocks, often on south-facing slopes. Bombus pennsylvanicus prefers to nest above ground. Bumble bees have not been found to be associated with specific environments but seem to proliferate in environments with high flower diversity and continuous blooming from April to July (Goulson 2003). Bombus pennsylvanicus has been observed in old growth spruce forest in the Smokies.
Reproduction
Eusocial. Reproduction is dominated by the queen, and eggs that are fertilized are female while eggs that remain unfertilized are male. This leads to a community where the females are diploids having twice the number of chromosomes as the haploid males. Nests in Wisconsin have up to 40 workers (Medler and Carney 1963). Bombus pennsylvanicus build wax “pockets” adjacent to the cells with the larvae and supply these with pollen for the larvae to feed on themselves. If several larvae share a common pollen “pocket”, there is competition and some will be larger than others.
Longevity
Only the queen bumble bees over winters. She has mated the prior to the winter and in the spring emerges from hibernating in search of a nest (Daly et al.). The rest of the bumble bee hive members only live between 14 and 25 weeks, which is the duration of the hive (Goulson 2003).
Ecology
In the Smokies, Bombus pennsylvanicus has been collected from tall ironweed (Veronia gigantea), red clover (Trifolium pretense), Queen Anne’s lace (Daucus carota), sunflower (Helianthus sp.) and the endemic Rugel’s ragwort (Cacalia rugelia). This species has rather indiscriminate tastes, having been recorded feeding on various flowers of the following families (Medler and Carney 1963): Asclepiadaceae (milkweeds), Asteraceae (composites), Boraginaceae (forget-me-nots and allies), Caprifoliaceae (honey-suckles), Convolvulaceae (morning-glories), Fabaceae (legumes), Lamiaceae (mints), Primulaceae (blazing stars), Rosaceae (roses and allies), Scrophulariaceae (snapdragons and allies), and Solanaceae (nightshades).
Associated Species
Some species of flower may depend especially heavily on bumble bees for pollination, especially monkshood (Aconitum), larkspur (Delphinium), and lousewort/wood betony (Pedicularis) because of the flowers’ deep corollas and the long tongues of certain bumble bee species.
Predators
In general Bombus species do not have many predators because of their vivid warning coloration. Skunks (Mephitis mephitis), Black bears (Ursus americana ), and other mammals will consume the comb, adult bees, and their brood. Shrikes (Lanius spp.) and Blue jays (Cyanocitta cristata) are both reported to feed on bumblebees. Wax moths (Aphomia sociella and Vitula edmandsii) and other insects may feed on the wax of the comb, the brood, and/or the adults (Kearns and Thomson 2001). Nothing is known about predation specific to the Smokies.
Parasites
Several species of mites (Acari), beetles (especially of the family Cryptophagidae), flies (Conopidae, Syrphidae, Tachinidae, Anthomyiidae), protozoans, and nematodes parasitize bumble bees or their colonies, or are non-harmful associates feeding on detritus or other material that does not effect the health of the bumble bees (Kearns and Thomson 2001). Bumble bees of the subgenus (or genus) Psithyrus do not have their own workers but instead take over the hives of other species of Bombus and induce their workers to raise the young of the invading queen. Some species of Bombus also engage in nest “usurpation” of others of their own or related species. Nothing is known about the parasites or other associates of Bombus in the Smokies.CONSERVATION BIOLOGY
Special Protection Status
Rangewide:
None.
The greatest threat to the bumble bee population is the lack of adequate habitat. The intensification of farming has changed fields rich in flower diversity to monocultures. Bombus populations need sites with high flower diversity and continuous blooming from April to July. A way to prevent this loss of habitat is to keep land near by farms unfarmed, and create a buffer zone (Goulson 2003). Many rare species of flower depend on native pollinators to effectively set seed.Regional:
None.Park:
All plants and animals are protected within the Great Smoky Mountains National Park. Collection requires a permit, which is usually granted only for research or educational purposes.Management Concerns
N/A
ACKNOWLEDGEMENTS
Drawings
N/A
Field Work
N/A
Maps
N/A
Photographs
N/A
References
Daly, H.V., J.T. Doyen, and A.H. Purcell III. 1998. Introduction to Insect Biology and Diversity. Oxford University Press, Oxford, UK.
Goulson, D. 2003. Bumble Bees Behaviour and Ecology. Oxford University Press, Oxford, UK.
Kearns, C.A. and J. D. Thomson. 2001. The Natural History of Bumblebees: A Sourcebook for Investigations. University Press of Colorado, Boulder, CO.
Medler, J.T., and D.W. Carney. 1963. Bumblebees of Wisconsin (Hymenoptera: Apidae). University of Wisconsin Research Bulletin 240, Madison, WI.
Michener, Charles D. 2000. The Bees of the World. John Hopkins University Press, Baltimore, MD.
Speight, D. L. 1967. The Bumblebees (Hymenoptera, Apidae, Bombinae) of East Tennessee. Master’s Thesis, University of Tennessee, Knoxville, TN, 95 pages.
Supporting Institutions
N/A
Text
P. E. Super and A. T. Moyer, 2003.
Eusocial: The most advanced form of social behavior: members cooperate in caring for young; at least two generations overlap; and the labor of reproduction is divided between reproductive and nonreproductive individuals.
