Osmia (Erythrosmia)


Family: Megachilidae
Subfamily: Megachilinae
Tribe: Osmiini
Genus: Osmia Panzer, 1806
Subgenus: Erythrosmia Schmiedeknecht, 1885
Common name: none


Osmia (Erythrosmia) are non-metallic bees that sometimes have red abdomens. The pubescence is pale and sometimes red (Michener 2007). They range in body length from 5.5–10 mm (Michener 2007).

Diagnostic characteristics

(modified from Michener 2007)

May be confused with

Osmia (Erythrosmia) may be confused with O. (Allosmia) due to a similar slender body shape, but can be differentiated by the differences in the number of segments on the maxillary palpus. Osmia (Erythrosmia) has four segments and sometimes a minute apical fifth segment, while O. (Allosmia) has five segments (Michener 2007).

Host associations

Osmia (Erythrosmia) are generalists and have been observed visiting Lamiaceae, Fabaceae, Boraginaceae, Crassulaceae, Brassicaceae, Cistaceae, Antirrhineae, and Campanulaceae (Müller et al. 1997; Müller 2018).

Nesting behavior

Osmia (Erythrosmia) have been observed nesting in snail shells where they use masticated leaves and broken snail shell pieces as building materials (Michener 2007). Osmia (Erythrosmia) andrenoides nest in small to medium-sized snail shells hidden under stones. Nests are comprised of one cell, which is partitioned with leaf pulp from Helianthemum. Cell walls are built from leaf pulp mixed with pebbles. Small pebbles and small sticks from plants are used to fill the space between the cell partition and the nest plug (Westrich 1989; Banaszak and Romasenko 2001; Müller 2018).


Osmia (Erythrosmia) contains four species (Müller 2018). None are known to occur in the U.S. or Canada.

Known invasives

There are no known invasives.


Osmia (Erythrosmia) can be found in Europe, southwestern Asia, the Mediterranean Basin, and East to Central Asia (Michener 2007).

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

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