Tepedino V. J., Griswold T. L., Durham S. L., Reproductive biology and flower visitors of two rare species of Sclerocactus (Cactaceae) in the southwestern United States, Western North American Naturalist, 2023, 83(4):445-453, doi: 10.3398/064.083.0402
The paper compares self-incompatibility in Sclerocactus wrightiae, partial self-compatibility in S. mesae-verdae and the need for pollinators in both species. The abstract identifies ground-nesting halictid bees as the probable main pollinators.