Osmia taurus

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Osmiini
Genus: Osmia Panzer, 1806
Subgenus: O. (Osmia) Panzer, 1806
Species: Osmia taurus Smith, 1873
Common name: taurus mason bee

Overview

Osmia (Osmia) taurus are black bees with intermixed yellow and black hairs on their face and long yellow hairs throughout the rest of their body (Wu 2006). Males tend to have a greenish metallic hue to the abdomen (Wu 2006). Female body length is 10–12 mm and male body length ranges from 8–11 mm (Wu 2006).

Diagnostic characteristics 

(modified from Yasumatsu and Hirashima 1950; Wu 2006)

  • Mouthparts usually much smaller than the length of the entire body when extended.
  • Terga usually without apical hair bands.
  • Female clypeus almost entirely smooth, shiny, and impunctate.
  • Female clypeus rounded or with acute median apical projection.
  • Female mandible with inner-most tooth truncate.
  • Female scopa pale reddish-yellow.
  • Male gonostylus slightly expanded subapically.
  • Male S2 large, often covering S3 to S4.
  • Male T6 and T7 without median emargination.

May be confused with 

Osmia taurus look similar enough to O. cornifrons that it likely led to the accidental introduction of O. taurus to the U.S. Osmia taurus can be differentiated from O. cornifrons by the truncate inner tooth of the mandible and the mostly shiny and impunctate basal half of the clypeus in O. taurus (Yasumatsu and Hirashima 1950). Males can be more difficult to differentiate but O. taurus tend to have abdominal hair with distinct red to orange hue, which can be faded in older specimens, whereas O. cornifrons have pale white abdominal hair, sometimes with black hair intermixed. The gonocoxites of O. taurus are also only slightly expanded subapically compared to the distinctly expanded gonocoxites of O. cornifrons.

Phenology

Osmia taurus adults have been recorded in flight from February to July in the U.S., and from January to October worldwide (GBIF 2019h).

Host associations 

Osmia taurus are generalists. They have been observed collecting from nine different plant families, where the flowers produce little nectar. They commonly collect from Juglandaceae, Fabaceae, and Altingiaceae (Quest 2009; Haider et al. 2013). Osmia taurus has also been used for orchard pollination in Asia (Maeta 1978).

Nesting behavior 

Osmia taurus nests in preexisting cavities in insect burrows in dead wood, straw tubes, and hollow stems. Cell partitions and nest plugs are composed of mud (Kitamura and Maeta 1969; Maeta 1978).

Distribution

Osmia taurus is native to Asia and is found predominantly in East China and Japan (Wu 2006). Due to its similarity with O. cornifrons, a commercial pollinator, O. taurus were accidentally shipped to the U.S. in 2000 (Russo 2016). O. taurus has now been collected throughout the East Coast of the U.S. (GBIF 2019h).


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

<p><em>Osmia taurus</em> female face, photo: Chelsey Ritner</p>
Osmia taurus female face, photo: Chelsey Ritner
<p><em>Osmia taurus </em>female lateral habitus, photo: Chelsey Ritner</p>
Osmia taurus female lateral habitus, photo: Chelsey Ritner
<p><em>Osmia taurus </em>female abdomen, photo: Chelsey Ritner</p>
Osmia taurus female abdomen, photo: Chelsey Ritner
<p><em>Osmia taurus</em> male face, photo: Chelsey Ritner</p>
Osmia taurus male face, photo: Chelsey Ritner
<p><em>Osmia taurus</em> male lateral habitus, photo: Chelsey Ritner</p>
Osmia taurus male lateral habitus, photo: Chelsey Ritner
<p><em>Osmia taurus </em>male abdomen, photo: Chelsey Ritner</p>
Osmia taurus male abdomen, photo: Chelsey Ritner
<p><em>Osmia taurus </em>male, diagram showing hidden sternum S8, diagram modified from Wu 2006</p>
Osmia taurus male, diagram showing hidden sternum S8, diagram modified from Wu 2006
<p><em>Osmia taurus </em>male, diagram showing dorsal view of genitalia, diagram modified from Wu 2006</p>
Osmia taurus male, diagram showing dorsal view of genitalia, diagram modified from Wu 2006