A small, solitary bee that specializes in pollinating cactus, Diadasia rinconis is the bee most often found on cactus flowers from April to June. Though they are called solitary, this isn’t strictly true. They do not create colonies, like honeybees. And, they don’t have a hierarchical structure but, in the Spring, in areas of bare soil, you might see hundreds of little, round bumps of soil, or structures that look like tiny mud chimneys. These odd structures are where female cactus bees, who have nested overwinter in large aggregations made up of thousands of individuals, emerge when the prickly pear and cholla cactus begin blooming. The nests are used only once; new female bees will make fresh nests in different locations. Males will often clump together by the thousands to wait for females to emerge from their ground nests, and will fight one another to earn the right to mate. The clumps of males clinging to each other as they try to reach the female are called “mating balls”.
Cactus bees are small to medium-sized, tawny golden in color with pale gold hairs on their abdomens. They are slightly larger than, and look a bit like, honey bees but rarely, if ever, sting. Female cactus bees have strongly banded abdomen and pollen carrying brushes/hairs on their hind legs and long hairs on their forelegs. Though they feed on nectar from a variety of flowers between April and September, they collect pollen exclusively from Opuntia and Cholla cactus.
Profile by Dana Ecelberger