The Apidae family is incredibly diverse and includes bumble, carpenter, honey, and long-horned bees. This diversity lends itself to a range of different nesting behaviors, from solitary to social, anywhere from in the ground to hollows in decaying wood. The most frequently seen native bees of this family visiting Echinacea are in the genera Ceratina and Melissodes. Less frequently seen are bees of the genera Bombus and Apis, as they are social bees and are therefore more attracted to plants that produce more abundant nectar than Echinacea. (Mader et al. 222-223)
(Mader et al. Attracting Native Pollinators: Protecting North America’s Bees andButterflies. 2011. The Xerces Society.)