Extracted from Jonathan Koch, James Strange, Paul Williams. 2012. Bumble Bees of the Western United States. A product of the U.S. Forest Service and the Pollinator Partnership with funding from the National Fish and Wildlife Foundation|
California bumble bee
Status: Uncommon, possibly in decline
Select food plant genera:
Cirsium, Trifolium, Monardella,
Astragalus, Penstemon, Abronia
ongue Length: Long
Distribution: Dark form distributed throughout coastal California,
Oregon and Washington; yellow form primarily distributed
throughout the Intermountain West and Rocky Mountains; both
forms co-occur in the Intermountain West along with
raising questions as to whether they are distinct species
Dark form can be confused with
Thorax anterior to black band between wing bases
predominately yellow, scutellum primarily black or
occasionally yellow intermixed, T1-3 predominantly
black, especially for coastal specimens and may also
be completely yellow except for small patches of black
on the apicolateral margins of T2 on specimens found
in the intermountain west and Colorado Rockies, T4
always yellow, face long.
Mid leg basitarsus with the distal posterior corner
sharply pointed (may be hidden by hair). Cheek
longer than broad. Hair of the face and top of
head predominantly black with yellow sometimes
intermixed. On the side of the thorax, the lower
anterior surface predominantly black, sometimes with
yellow intermixed, corbicular fringes black. Hair length
short and even. Yellow
males can be
extremely hard to distinguish from
Extracted from Bumble Bees and Cuckoo Bumble Bees of California by Thorp, R. (1983). |
Bombus caJifbmkus F. Smith, 18S4, CaL Hymen. British Mus., 2:400. q, m. Hototype q, California (#17B1223 BMNH).
Bombus consangulneus Handlirsch, 1888, Ann. K. K. Naturhist. Hofmus. 3239. q, w, m. Type and its location unknown.
Geographic range (Map 7). W of 100° longitude; Alberta to Colorado W to British Columbia and Baja California del Norte.
California representative records. ALAMEDA Co.: Alameda; Arroyo Mocho, 32 km S Livermore; Berkeley; Pleasanton; Teste. ALPINE Co.: Woodfords. AMADOR Co.: Sutter Creek;
Volcano; White Station. BUTTE Ca: Chico; W. branch Feather River. CALAVERAS Ca: Murphys, 610 m; Valley Springs, 2 km E. COLUSA Ca: Lodoga, 10 km W. CONTRA COSTA Ca: Antioch; Briones Hills; Concord; Martinez; Mt Diablo; Orinda Village; Point Richmond; Walnut Creek. DEL NORTE Ca: Crescent City. EL DORADO Ca: Angora Lakes; Latrobe; PlacerviUe; Pollock Pines. FRESNO Ca: Auberry; Firebaugh; Huntington Lake; Mer-cey Hot Springs; Squaw Valley. GLENN Ca: Artois; Fruto; Grindstone Canyon, 11 km N Weir Canyon. HUMBOLDT Ca: Areata; Ferndale; Fort Seward; Kneeland; Orick. KERN Ca: Fra-zier Park, 2 km S. LAKE Ca: Elk Mtn.; Lake Pilbbury, Lower Lake. LASSEN Ca: Blue Lake, South Warner Ridge; Hallelujah Junction; Plumas. Los ANGELES Ca: Avalon, Santa Catalina Island; Claremont; Crystal Lake; Malibu; Pasadena; San Gabriel Canyon. MADERA Ca: Bass Lake; Nipinnawasee; Oakhurst. MARIN Ca: Alpine Lake; Bolinas; Fairfax; ML Tamalpais; Novato; Oiema; Pt Reyes; Tomaks. MARIPOSA Ca: Coulter-ville; Exchequer Dam; Mariposa; Yosemite Valley. MENDOCINO Ca: Fort Bragg; Hopland; Manchester, Westport; Willits. MERCED Ca: Livingston; Los Banc*; W Panoche Hills. MODOC Ca: Adin Pass, 1525 m; Alturas; CedarvOle; Davis Creek; Ft. Bidwell. MONTEREY Ca: Arroyo Seco Camp; Big Sur; Carmel-, Carmel Valley; Junipero Sena Peak; Santa Lucia Mtns.; King City; Soledad. NAPA Ca: Calistoga; Napa; Pope Valley. NEVADA Ca: Boca; Emigrant Gap; Nevada City; Ruckers Lake. ORANGE Ca: Newport Beach; San Clemente; Trabuco Canyon; Yorba Linda. PLACER Ca: Alia; Auburn; Forest Hill; RoseviQe. PLUŽMAS Ca: Bucks Lake; Meadow Valley, Quincy. RIVERSIDE Ca: Anza; Banning; Corona; Ebinore; Hemet; Idyllwitd; Indio; Riverside; Temecula. SACRAMENTO Ca: Folsom; Gait; Michigan Bar, Sacramento. SAN BENITO Ca: Bitterwater; Hollister; Idria; Pinnacles Natl. Mon. SAN BERNARDINO Ca: Cajon Valler, Forest Home; Lake Arrowhead; Loma Linda; Oak Glen Lodge. SAN DIEGO Ca: Endnitas; La Jolla; Sunnyside; Warner Springs. SAN FRANCISCO Ca: San Francisco. SAN JOAQUIN Ca: Stockton. SAN LUB OBISPO Ca: Atascadero; Mono Bay; San Luis Obispo; Shandon; Simmler. SAN MATEO Ca: Daly City, Patifka; San Bruno Mtns. SANTA BARBARA Ca: San Miguel Island; Santa BarŽbara; Sania Rosa Island; Zaca Peak. SANTA CLARA Ca: Gilror. ML Hamilton; Palo Alto; San Jose. SANTA CRUZ Ca: ML HerŽman; Soquel; Watsonville. SHASTA Ca: Burner* Hat Creek P.O.; Shingletown; Viola. SIERRA Ca: Goodyear's Bar; Sierraville. SISKIYOU Ca: Etna; Mt Shasta City. SOLANO Ca: VacaviDe; Val-lejo. SONOMA Ca: Cazadero; Cloverdale; Glen Ellen; Monte Rio; Petaluma; Santa Rosa; Shell Beach. STANISLAUS Ca: Empire; La Grange; Patterson; Turlock. SUTTER Ca: Marysville Buttes. TEHAMA Ca: Red Bluff. TULARE Ca: Giant Forest; Kaweah; Mineralking; Porterville. TUOLUMNE Ca: Big Oak Flat; Columbia; Dardanelle; Mather; San Pedro Dam; Sonora Pass; Strawberry. VENTURA Ca: Fillmore; Oxnard; Santa Paula. YOLO Ca: Capay; Davis; Dunnigan; Elkhorn Ferry; Putah Canyon.
Seasonal flight period (Fig. 7). QUEENS (380): early February to early October. WORKERS (568): early March to late October. MALES (600): early May to late October.
Flower records. QUEENS (78): Leguminosae 53%; Compositae 12%. WORKERS (101): Legminosae 34%; Compositae 32%. MALES (97): Compositae 33%; Leguminosae 27%. Total 276 in 24 families with 52 genera as follows: Agastache: lw; Althaea: 3w, 2m; Amsinckht: lw; Antirrhinum: lq, lw; Astragalus: 13q,
Fig. 7. Histograms of seasonal flight activity for Bombus californicus.
lOw, lm; Brassko: 3q; Canna: lm; Casdlkja: lq; Centawea: 6w, 9m; Chhrogahtm: 5m; Clrshtm: 2q, 24w, 8m; ClarkUt: 3m; Col-linsia: 2w; Coreopsis: 7m; Cosmos: 4m; Delphinium: 2q, 4m; Ertodkfyon, lw; Eriogonum: 3m; Eschschobia: 2w; Foenkuhim: lw, Ghxyrrhha: 5m; Haphpappus: 2m; Helianthus: lq, 2w; Isomeris: lq; Lathyms: lq, 4w, Llnarkt: lw; Lonkxra: 3w, Lotus'. lq, 9w, lm; Lupinus: 5q, 8w; hiedkago: 2q, 10m; Melibtus: 2m; Mentha: lw, lm; Menaella: lq; MonardeUa: lm; Opuntia: lq; Orthocarpus: 4q, 3w, Penstemon: lw, 4m; Potentilla: 2w; Raphama: 2q, 4w, 2m; Rhododendron: 2q, 2m; Ribes: lm; Rosa: lq; Saltx: lq; Salvia: 4q, 3w, 2m; Scabiosa: 2m; Solidago: lm; Stachys: lw, 4m; Trkhostema: lm; Trffbhum: lq, 3w, 5m; Kfcfe: 21q, 4w, 2m; Wyethia: 6q; Zinnia: 2m.
Discussion. B. californicus is most closely related to B. fsrvidus and is considered by Milliron (1973a) to be conspecific with it. However, they are ecologiŽcally separated where sympatric (Hobbs, 1966a) and show no signs of intergradation in broad areas of sympatry. They are recognized principally by difference in color pattern: B. californicus has predominantly black hair on thoracic pleura, scutel-lum, and metasomal tergites 1 to 3; B. fervidus has yellow hair on these areas.
Some males in California are indistinguishable from the more yellowish color variant con-sanguineus. They approach the color of B. fervidus*
but may be separated from jervidus by having more lemon-yellow hair and some black hair medially and laterally on metasomal tergites 1 to 3. No females in California can be assigned to consanguineus. Thus, its subspecific status is not appropriate.
Hobbs (1966a) described the biology of B. cali-fornicus and documented the ecological differences in nest habitats for caltfbrnicus (wooded areas of the foothills) and Jervidus (prairie) in southern Alberta. He also found that Psithyrus insubris and P. suckleyi females had invaded nests of B. caltfbr-nicus% and the former species produced some adults.