Bumble Bees of the Western United States - USDA Forest Service

Color plates of male bumble bees are provided, but hair colorationin males is not the most reliable character. Thus questionableidentifications of a male may require an expert as the mainmorphological differences are found on the male genitalia.HabitatWhile they are closely related to the non-native European honeybee (Apis mellifera), bumble bees do not produce commercialquantities of honey, and are used less often in commercial pollination.However, bumble bees are arguably more important in thepollination of native flowers in natural ecosystems of the UnitedStates, and have evolved in a broad array of habitats, from thePuget Sound in Washington to the deserts of the Southwest.As a genus, bumble bees inhabit temperate regions worldwideand several species are even known from the equatorial regionsof the Neotropics. However, bumble bees dominate the pollinationlandscape in northern climates. They are importantin boreal forests, cold prairies, coastal plains, and mountainhabitats. Their ability to survive in cold climates makes themthe primary pollinators of alpine flowering plants and some ofthe few organisms that can survive in an arctic environment orat high elevations where temperatures drop well below freezingin the winter.When looking for bumble bees it is best to go to where flowers areblooming. Do not expect to find a nest as they are often undergroundin abandoned rodent burrows; instead focus on bumblebees visiting flowers. In forested areas, we most commonly encounterbumble bees along stream courses, in meadows, recentlyBombus terarius foraging on Asteraceae.burned or logged areas, or on flowers by roadsides. Each differentmicro-habitat provides different resources and a greater chanceto encounter a new species of bumble bee. For example in CacheValley, Utah we find several species of bumble bees in the agriculturalfields at the valley floor (1400m or 4600’), another groupof species in the mountain canyons of the Cache National Forest(1500-2500m or 5000’-8000’) and a third group of species in thehigh meadows (above 2500m or 8000’). Furthermore, we find thattwo field sites at the same elevation located 1km apart can havevery different fauna if the flowering plants in bloom are different.Bumble Bees of the Western United States 7