Once one of the most common bumble bees across the eastern US, the American bumble bee has declined nearly 89% over the past 20 years and is now under review for Endangered Species Act listing.
§ Quick facts
§ Encyclopedia
Bombus pensylvanicus, the American bumblebee, is a threatened species of bumblebee native to North America. It occurs in eastern Canada, throughout much of the Eastern United States, and much of Mexico.
Source: Wikipedia — Bombus pensylvanicus Licensed under CC BY-SA 4.0
§ Identification
Field marks. Medium-large bumblebee with yellow thorax, mostly black abdomen, and yellow band across waist; relatively long face compared to other US bumblebees.
Similar species. Two-spotted Bumble Bee (yellow spots on abdomen). American Lemon-Cuckoo Bumblebee (parasitic, no pollen baskets). Many Bombus species are nearly identical and require expert ID.
Voice. Buzz during flight; louder "sonication" buzz when shaking pollen from anthers.
§ Diet & behavior
Diet. Nectar and pollen from a wide variety of flowering plants. Important pollinator of tomato, eggplant, and other crops requiring "buzz pollination" (sonication).
Behavior. Was once the most common bumblebee across much of the central and southern US; populations have declined ~89% in the past 20 years. Causes appear to include pesticide exposure (especially neonicotinoids), introduced parasites from commercial honey bees, habitat loss, and possibly climate-driven range shifts. Currently a candidate for federal endangered listing.
§ Range
Most of the eastern, central, and southwestern US
§ Habitat
Open fields, pastures, prairies, gardens with diverse native flowers
§ Threats
Pesticide exposure (especially neonicotinoids), habitat loss, disease spillover from commercial bumble bee colonies, climate stress.
§ Conservation status
According to the IUCN Red List, the american bumble bee is currently classified as Vulnerable.
§ What helps
Plant native flowers blooming spring through fall. Stop neonic use. Leave fall leaves and standing stems for nesting queens.
§ Further reading
- Wikipedia — Bombus pensylvanicus
- www.fws.gov — authoritative profile of Bombus pensylvanicus
- IUCN Red List · taxon 44937464
- iNaturalist · taxon 118880
- GBIF occurrence records
- Encyclopedia of Life — Bombus pensylvanicus
§ Sources cited
- Xerces Society Bumble Bee Atlas
- USFWS American Bumble Bee Status Review
- Bumble Bee Watch
- IUCN Red List 2014
