Osmia (Allosmia)


Family: Megachilidae
Subfamily: Megachilinae
Tribe: Osmiini
Genus: Osmia Panzer, 1806
Subgenus: Allosmia Tkalců, 1974
Common name: none


Osmia (Allosmia) are non-metallic bees ranging in body length from 7.5–11 mm. They commonly have pale to red pubescence that forms tergal fasciae. Males vary greatly in size. The large males are often larger than the females (Michener 2007).

Diagnostic characteristics

(modified from Michener 2007)

May be confused with

Male O. (Allosmia) may be confused with male O. (Erythrosmia) due to the broad, basal depressions on S6 and the carinate hind coxae (Michener 2007). They can be differentiated by the number of segments on the maxillary palpus: 5 on O. (Allosmia), 4 on O. (Erythrosmia) (Michener 2007). It has been recommended that these subgenera be merged due to the similar characteristics (Michener 2007).

Host associations

Osmia (Allosmia) are generalists, and have been observed visiting Fabaceae, Convolvulaceae, Brassicaceae, Caryophyllaceae, Asteraceae, Boraginaceae, Cistaceae, Lamiaceae, Resedaceae, Papaveraceae, Campanulaceae, and Oxalidaceae (Banaszak and Romasenko 1998; Müller 2018b).

Nesting behavior

Osmia (Allosmia) construct the cells in their nests in abandoned snail shells. Partitions and nest plugs are often made out of chewed leaf materials. Sometimes the chewed leaf material is mixed in with stones, broken snail shells, and dirt. Shells are then often buried in the ground or moved and hidden under rocks or vegetation (Westrich 1989; Müller 2018).


Osmia (Allosmia) contains nine species (Müller 2018b). None are known to occur in the U.S. or Canada.

Known invasives

There are no known invasives.


Osmia (Allosmia) can be found in central, southern, and eastern Europe, northern Africa, and southwestern and northern Asia (Michener 2007; Nadimi et al. 2013; Müller 2018).

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

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