Osmia (Tergosmia)


Family: Megachilidae
Subfamily: Megachilinae
Tribe: Osmiini
Genus: Osmia Panzer, 1806
Subgenus: Tergosmia Warncke, 1988
Common name: none


Osmia (Tergosmia) are robust, non-metallic bees that range in body length from 6.5–13 mm (Michener 2007).

Diagnostic characteristics

(modified from Michener 2007)

May be confused with

Osmia (Tergosmia) may be confused with O. (Ozbekosmia) because both have similar non-metallic and pale-haired bodies, females with mandibles that are tridentate and medially narrowed, male S2 and S3 have straight apical margins, and male S5 strongly emarginate with a fringe of hair in the emargination (Michener 2007). Osmia (Tergosmia) can be differentiated from O. (Ozbekosmia) by the shape of the clypeal margin in females, the strong lateral teeth on male T6, and they lack the heavily sclerotized apical projection of O. (Ozbekosmia) (Michener 2007).

Host associations

Osmia (Tergosmia) have been observed collecting pollen from Fabaceae, Campanulaceae, Brassicaceae, Lamiaceae, and Asteraceae (Rozen et al. 2010).

Nesting behavior

Osmia (Tergosmia), similar to O. (Ozbekosmia), use whole petals or large pieces of flower petals to construct the cell walls in their nests. The cell walls consist of three layers: two layers of petals with a thin layer of mud in the middle (Rozen et al. 2010). Petals used for nests were collected from Geranium, Helianthemum, Linum, Hieracium, and Ononis. Nests are constructed in preexisting rock cavities or in excavated burrows in hard soils and consist of 1–10 cells depending on the species (Rozen et al. 2010). Osmia tergestensis nests in cavities under or in between rocks. The cells are not glued to a substrate. In narrow cavities, the space is filled with dirt (Müller 2018b). Osmia lunata nests in excavated burrows in the ground. The burrows are hidden under small shrubs (Müller 2018b).


Osmia (Tergosmia) consists of seven species (Müller 2018b). None are known to occur in the U.S. or Canada.


Osmia (Tergosmia) are known to occur in the Mediterranean Basin, Uzbekistan, and Turkmenistan (Michener 2007).

​Distribution map generated by Discover Life -- click on map for details, credits, and terms of use.

<p><em>Osmia agilis </em>female face, photo: Chelsey Ritner</p>
Osmia agilis female face, photo: Chelsey Ritner
<p><em>smia agilis </em>female lateral habitus, photo: Chelsey Ritner</p>
smia agilis female lateral habitus, photo: Chelsey Ritner
<p><em>Osmia agilis </em>female abdomen, photo: Chelsey Ritner</p>
Osmia agilis female abdomen, photo: Chelsey Ritner