American Bumble Bee

Pronunciation

How to pronounce Bombus pensylvanicus: //ˈbɒmbəs ˌpɛn.sɪlˈvæn.ɪ.kəs//

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Summary

Bombus pensylvanicus, the American Bumble Bee, is a threatened species with significant population declines in North America, especially in the northern parts of its range. It is characterized by its distinctive coloring and role as a pollinator in open habitats.

Physical Characteristics

In typical females, the thoracic dorsum is yellow anteriorly and black posteriorly, and the first three tergal segments are yellow contrasting with black distal segments. Large queen measures 22–26 mm compared with workers at 13–19 mm. Males have an outward penis valve head with a broad banana shape and often have extensive yellow on the thoracic dorsum posteriorly.

Identification Tips

Potential confusion with B. fervidus and B. auricomus; distinguishing characteristics include the yellow thoracic dorsum and black T4 in B. pensylvanicus, while B. fervidus has a yellow T4.

Habitat

Prefers open farmland and fields; nests in sheltered locations such as long grass, hay bundles, and human-made structures.

Distribution

Ranges from eastern Canada and throughout the Eastern United States to much of Mexico, with severe population declines in northern areas.

Diet

Feeds primarily on nectar and pollen from flowers, notably clover (Trifolium) and sunflowers (Helianthus).

Life Cycle

Reproductive cycle begins in February, peaking in July/August with male mating. Colony development includes queen laying eggs, which develop based on fertilization status.

Reproduction

Females can lay eggs without mating (haplodiploidy) leading to male offspring from unfertilized eggs, while fertilized eggs become female workers or new queens.

Predators

Predated upon by various mammals (skunks, raccoons), birds, wasps (e.g., beewolves), and invertebrates (e.g., robber flies, crab spiders).

Conservation Status

Listed as Vulnerable by the IUCN Red List of Threatened Species. Declines noted particularly at the northern margin of its range.

Ecosystem Role

Functions as a key pollinator for various flowering plants in its habitat.

Economic Impact

Considered significant due to its role in pollination which supports agriculture and biodiversity.

Evolution

Part of the genus Bombus, which has undergone changes in population dynamics and genetic structures due to habitat loss and agricultural practices.

Similar Taxa

• Bombus sonorus
• Bombus fervidus
• Bombus auricomus
• Bombus terricola

Misconceptions

Despite its name, Bombus pensylvanicus is not the most widespread bumblebee species; its populations have steeply declined in recent years.

Tags

• Bumblebee
• Pollinator
• Threatened Species
• North America