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