Caupolicana electa

Distinguished from other Caupolicana species by its large size—females exceed 20 mm, while most congeners are under 15 mm. The basitarsus of the hind leg in females is notably broad and flattened compared to C. yarrowi. Males can be separated from C. fulvicollis by the density of facial pubescence and antennal proportions. The combination of large body size, black coloration with pale abdominal bands, and spring flight period separates it from superficially similar anthophorine bees.

A large, robust bee with females measuring 18–22 mm and males slightly smaller. The body is densely hairy with a velvety texture. Coloration is predominantly black with pale, often yellowish or whitish, hair bands on the abdomen. The hind legs of females are modified for pollen collection with dense scopal hairs. Males have longer antennae and may show more extensive pale markings on the face. The wings are dark with a subtle iridescent sheen.

Open, sandy or loamy soils in coastal and interior regions. Associated with scrubland, chaparral edges, and open woodland clearings. Requires exposed ground for nesting.

Western North America, from southern California northward through Oregon and into southwestern Washington. Records extend eastward into Nevada, Arizona, and New Mexico.

Spring-active; adults fly primarily from March through May, with peak activity in April. Emergence timing varies with elevation and latitude.

Adults feed on nectar and collect pollen from a variety of flowering plants. Specific host plant associations have been documented with Camissonia, Oenothera (Onagraceae), and other spring-blooming herbs.

Solitary nesting species. Females excavate burrows in sandy soil and construct individual cells lined with a transparent, cellophane-like secretion. Each cell is provisioned with a pollen-nectar mass and receives a single egg. Larvae develop within the sealed cells, with pupation occurring in summer and adults emerging the following spring. No evidence of social behavior or multiple generations per year.

Females are solitary ground-nesters, excavating burrows with multiple cells. Nest architecture includes a waterproof, transparent cell lining secreted from the Dufour's gland—a diagnostic trait of the family Colletidae. Males patrol nesting areas and vegetation patches seeking females. Both sexes are diurnal foragers with rapid, direct flight patterns.

Pollinator of spring-blooming native plants, particularly in early-successional and open habitats. Its large size enables effective pollen transfer for plant species with deeper floral tubes. As a ground-nesting bee, it contributes to soil aeration and nutrient cycling in its nesting aggregations.

Occasional visitor to gardens with native plantings, though rarely abundant enough to be agriculturally significant. Not known to sting readily; females possess stings but are non-aggressive. Provides ecological value as a native pollinator in habitat restoration contexts.

• Caupolicana yarrowiOverlaps in range and habitat; smaller (females 12–16 mm), with narrower hind basitarsus and more extensive reddish coloration on legs.
• Caupolicana fulvicollisSimilar size range; males distinguished by sparser facial pubescence and different antennal proportions. Females show more extensive pale hair on the thorax.
• Anthophora spp.Similar large, robust, fast-flying bees with pale abdominal bands; separated by two submarginal cells in forewing (three in Caupolicana) and different nesting biology.

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life