Centris – mining bees (family Apidae)
By Lisa Schonberg and Mace Vaughan (Xerces Society) and Gretchen LeBuhn (SFSU)
Genus summary: Centris is a genus restricted to the New World with about 77 species in North America (Michener 2000). It is most abundant and diverse in the tropics and the deserts of the southwest U.S. and northern Mexico and rare elsewhere (Michener 1994).
Floral relationships: Centris are long-tongued, which enables them to extract provisions from deep flowers. Most Centris, with the exception of desert species, visit plants that offer oil instead of nectar, primarily in the family Malpighiaceae (O’Toole & Raw 1999).
Nesting habits: Centris are solitary bees. They nest in soil, logs or branches (Colville et al. 1983), or in the abandoned nests of mud dauber wasps (Michener 1994).
Diagnostic characteristics: Most Centris are compact, hairy, very robust bees. They are moderate to large and between 0.4 to 1.1 inches long. With the exception of very large Centris spp, Centris are adept fliers that can fly very fast and also hover well (Michener 2000). Most species have a red, greenish or metallic bluish abdomen, sometimes with yellow bands on top or spots on their sides (Michener 1994). Centris have morphological adaptations to collect floral oils; on their legs are beautiful collecting combs of flat and blunt bristles (Michener 2000) that look like massive pollen scopa.
Similar taxa: Centris are similar to Anthophora, but with longer and denser “hairs” on legs (Michener 1994).
Known conservation concerns:
Interesting fact: There is a diversity of interesting mating systems among Centris spp.. In most species, males are generally sexually aggressive and mark mating territories which they maintain for days at a time (Michener 2000). In some species, the males smell the female to track her down while she is still in her burrow, and dig into the ground while the female is emerging (Rozen & Buchmann 1990). Males will chase after almost anything that enters their territory, even a tossed pebble.
Additional resources: Nesting habits: Colville et al. (1983).