Osmia (Osmia)

Taxonomy

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

Overview

Osmia (s. str.) are robust bees with long hairs that vary in color. Some Osmia (s. str.) are completely black, others have metallic hints, while others are strongly metallic (Michener 2007). They range in body length from 8.5–16 mm (Michener 2007). In 2013, Osmia subgenera Monosmia and Orientosmia were integrated into Osmia (s. str.) by Haider et al. 2013.

Diagnostic characteristics

(modified from Michener 2007)

Antenna reaches the propodeum.
Hind coxa without strong longitudinal carina along inner ventral angle.
Genal area has a small shining depression below and behind the lower margin of the eye.
Malar space is as long as the width of the scape.
Middle flagellar segments are twice as long as they are broad.
Proboscis does not reach beyond the middle of the thorax in repose.
Female clypeus in some cases is produced forward at a strong angle and does not overhang the labrum. In other cases, the clypeus is ordinary, truncate, and overhangs the base of the labrum.
Male T7 with a small median emargination.

May be confused with

Osmia (s. str.) may be confused with O. (Neosmia) due to their robust bodies with long hairs; however, they can be differentiated by the characteristics listed above (Michener 2007).

Host associations

In Osmia (s. str.), some species are generalists while others are specialists. Many are specialists on Boraginaceae and Fabaceae. Other Osmia (s. str.) species are generalists on Ranunculaceae, Fabaceae, Papaveraceae, Cistaceae, Rosaceae, Brassicaceae, Salicaceae, Juglandaceae, Altingiaceae, Lamiaceae, Boraginaceae, and Caprifoliaceae (Westrich 1989; Müller 2012; Haider et al. 2013; Müller 2018b).

Nesting behavior

Osmia (s. str.) species use a diverse range of nesting sites and materials. Cell partitions and nest plugs are comprised predominantly of mud (Müller 2018b). They have been observed nesting in insect burrows in dead wood and in the ground, pithy stems, hollow stems, abandoned cells in other bee nests, empty snail shells, crevices between rock, as well as in man-made materials such as crevices in walls, between shingles on houses, metal tubes, between folded newspapers, and drilled borings in wooden blocks (Ducke 1900; Graeffe 1902; Friese 1923; Kitamura and Maeta 1969; Rust 1974; Maeta 1978; Westrich 1989; Bosch et al. 1993; Müller et al. 1997; Banaszak and Romasenko 2001; Ivanov 2006; Müller 2018b).

Diversity

Osmia (s. str.) consists of 29 described species (Michener 2007).

Known invasives

Osmia (s. str.) has five known introduced species in the U.S.: O. cornifrons, O. cornuta, O. melanocephala, O. taurus, and O. ribifloris. Further, at least one native North American species (O. lignaria) has been documented in Spain (Ortiz-Sanchez 2011), although it is unclear if they have become established.

Osmia cornifrons is native to eastern China and Japan. They were introduced to North America, Denmark, and Korea intentionally in the 1960s for commercial pollination of fruit crops (Russo 2016).

Osmia cornuta is native to Europe, North Africa, and Asia. They were most likely intentionally introduced in the 1980s to the United States; however, it is unclear if they have become established (Russo 2016).

Osmia taurus is native to eastern China and Japan. They were introduced to eastern North America in the 2000s, most likely accidentally brought along with the intentionally introduced O. cornifrons (Russo 2016).

Osmia ribifloris is native to the western U.S. They were intentionally introduced to the eastern U.S. in the 2000s for commercial pollination (Russo 2016).