Calliopsis barri

Mining bees

Family: Andrenidae · Class: Insecta · Order: Hymenoptera

Calliopsis barri is a small, solitary mining bee endemic to sand dunes in the Columbia Basin of the western United States. This species belongs to the family Andrenidae and was originally described as Nomadopsis barri by Rozen in 1959, but was later transferred to the genus Calliopsis when Nomadopsis became a subgenus of Calliopsis (Michener 2000). Like other members of the Calliopsis genus, this species exhibits the typical mining bee morphology with a compact body structure adapted for ground-nesting behaviors. The species has an extremely limited distribution, known only from sand dune habitats at two locations: Rexburg, Idaho, and Sisters, Oregon (Xerces Society). This restricted range makes C. barri one of the rarest bees in North America, confined to specialized sandy environments within the Columbia Basin ecosystem. The species appears to be endemic to this biogeographic region, with no records from other areas despite extensive surveys of similar habitats. Calliopsis barri inhabits open sand dune systems where loose, well-drained sandy soils provide suitable nesting substrate. These environments are characterized by sparse vegetation and dynamic wind-driven sand movement. The specific microhabitat requirements for nesting sites remain poorly documented, though like other ground-nesting bees, females likely excavate burrows in sandy slopes or flat areas with appropriate soil compaction and drainage characteristics. This species exhibits highly specialized foraging behavior, visiting exclusively small-flowered legumes (Fabaceae) for nectar and pollen collection. This narrow host plant preference indicates C. barri is an oligolectic bee, meaning it has co-evolved with specific plant species rather than being a generalist forager. The timing of adult activity likely coincides with the flowering periods of these leguminous plants, though specific phenological data are lacking. Nesting habits remain largely unknown, but females presumably construct individual ground nests typical of other Calliopsis species, where they provision cells with pollen balls and lay single eggs. Calliopsis barri currently receives no formal protection under federal or state endangered species legislation. The Xerces Society has classified the species as Vulnerable on their Red List, recognizing the conservation concern posed by its extremely limited distribution (Xerces Society). The known populations occur on unprotected sand dune habitats, making them vulnerable to habitat destruction, recreational activities, and development pressures. Sand dune ecosystems face ongoing threats from off-road vehicle use, residential development, and invasive plant species that can stabilize dunes and alter the natural disturbance regimes these specialized bees require. Conservation recommendations include protecting existing sand dune habitats, conducting surveys to determine the full extent of the species' distribution, and researching basic life history requirements including nesting preferences and host plant relationships. Given the species' apparent rarity and habitat specificity, immediate conservation attention is warranted to prevent potential extinction. Climate change may pose additional threats by altering precipitation patterns and plant community composition in the Columbia Basin region.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.