Genus: Osmia Panzer, 1806
Subgenus: Melanosmia Schmiedeknecht, 1885
Common name: none
Osmia (Melanosmia) are robust bees that can vary from non-metallic black or blue to vibrant metallic blue, green, or purple. They lack apical tergal fasciae of plumose hairs, and range in body length from 6–14 mm (Michener 2007).
Osmia (Melanosmia) are very diverse bees and, unfortunately, there are many exceptions that can cause this subgenus to key out with other groups.
Host associations for many of the species are unknown. For those that are known, floral associations vary among species. Osmia inermis and O. steinmanni have been observed collecting from Fabaceae and Ericaceae (Hicks 2009; Müller 2018). Osmia nigriventris is a generalist on the families Ericaceae, Fabaceae, and Rosaceae (Müller 2018). Osmia xanthomelana and O. alticola are specialists on Fabaceae (Müller 2018b). Osmia pilicornis has been observed visiting Lamiaceae, Boraginaceae, Fabaceae, Asteraceae, Asparagaceae, Caprifoliaceae, Rosaceae, and Violaceae (Prosi et al. 2016; Müller 2018). Osmia parietina has been observed visiting Fabaceae, Crassulaceae, Rosaceae, and Plantaginaceae (Müller 2018). Osmia maritima has been observed visiting Fabaceae, Rosaceae, Brassicaceae, and Asteraceae (Müller 2018). Osmia disjuncta has been observed visiting Ericaceae and Salicaceae (Müller 2018).
Nesting habits of O. (Melanosmia) vary considerably among even closely related species. Typically O. (Melanosmia) species nest in cavities they either find or excavate themselves, although at least one species, Osmia xanthomelana, is known to create exposed nests on grass or rocks (Michener 2007; Müller 2018). Nests may be built in abandoned insect burrows, holes in wood, under stones, within fissures in rocks, in hollow stems and in excavated burrows in sandy soils, earthen banks, or cliffs (Lovell 1909; Michener 2007;; Müller 2018). O. (Melanosmia) use a number of different materials in the construction of their nests, including mud, sand, leaves masticated into a pulp, pith from stems, plant resin, wood fibers and a substance secreted from their mouthparts (Krombein 1967; Rust and Clement 1972; Parker 1975; Frohlich 1983; Parker 1986; Michener 2007; Müller 2018).
Osmia (Melanosmia) consists of 135 species, 19 of which are found in the Palearctic (Müller 2018).
There are no known invasives.
Osmia (Melanosmia) can be found in southwestern and northern Asia, Europe, throughout the U.S. from Florida to Alaska, and from Nuevo Leon to Baja California in Mexico (Michener 2007). They prefer montane regions and are less common in desert areas (Michener 2007).