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Western Bumblebee

picture of a Western Bumblebee

The white tail of the Western Bumblebee (Bombus occidentalis) makes it a fairly easy species to identify. Finding one is an altogether different story.

Once common throughout the Western United States, the population experienced a dramatic decline. Scientists hypothesize that the species contracted a parasitic fungi, Nosema bombi, when it was exported to Europe to create commercial colonies for pollinating greenhouse plants.

When the colonies were re-imported, escaped greenhouse species spread the fungus through the native population.

Three different Bombus occidentalis populations are recognized, each with a slightly different look. The Rocky Mountain and Pacific Northwest populations have the white tail. The Rocky Mountain population also has a yellow ring around the middle of the abdomen.

© 2010 Patricia A. Michaels