Genus: Osmia Panzer, 1806
Subgenus: O. (Osmia) Panzer, 1806
Species: Osmia cornifrons Radoszkowski, 1887
Common name: Japanese hornfaced bees
Osmia (Osmia) cornifrons are black bees with a copper luster (Wu 2006). Females have light yellow hair on the thorax and T1–T3; T4–T6 are covered with dark brown hair (Wu 2006). Males primarily have pale hair on their head, thorax, and abdomen, often with black hairs intermixed (Wu 2006). Female body length ranges from 8–12 mm, and male body length ranges from 8–10 mm (Wu 2006). O. cornifrons is used worldwide as a pollinator of commercial crops, especially apple trees, and was successfully introduced to the U.S. in the 1970s (Batra 1978).
Osmia cornifrons look similar enough to O. taurus that it likely led to the accidental introduction of O. taurus to the U.S. Osmia cornifrons can be differentiated from O. taurus by the acute inner tooth of the mandible and the densely punctate basal half of the clypeus in O. cornifrons (Yasumatsu and Hirashima 1950). Males can be more difficult to differentiate, but O. taurus tend to have abdominal hair with a distinct red to orange hue, which can be faded in older specimens, and O. cornifrons have pale white abdominal hair, sometimes with black hair intermixed. The gonocoxites of O. cornifrons are also distinctly expanded subapically compared to the only slightly expanded gonocoxites of O. taurus.
Osmia cornifrons have been recorded in flight in the U.S from March to June, with the majority of occurrences through April. In Asia, specimens have been recorded from January to August (GBIF 2019b).
Osmia cornifrons are a polylectic species and have been observed visiting plants within the families Rosaceae, Ericaceae, Caprifoliaceae, Aceraceae, Leguminosae, Fabaceae, and Brassicaceae, with a preference for Rosaceae (Maeta 1978; Quest 2009; Haider et al. 2013). O. cornifrons are also important pollinators for fruit crops and are commonly used commercially for the pollination of apple orchards (Matsumoto and Maejima 2010).
Osmia cornifrons is a solitary bee that nests in preexisting cavities. In the New World, nests can be found in reeds, bamboo, holes within trees, insect borings in dead wood, and hollow stems, and in the Old World, nests can be found in cracks in bark, and cracks or crevices in rock (Maeta 1978). Nests cells are constructed of mud and leaf pulp (Maeta 1978). O. cornifrons will forage up to 130 m from the nesting site (Kitamura 1974).
Osmia cornifrons is native to eastern Asia and has been found in Japan and Korea as well as the southeast coast of Russia (Yasumatsu and Hirashima 1950). O. cornifrons was intentionally introduced to the eastern U.S. from Japan in the 1970s to increase crop pollination (Batra 1979). In the U.S., O. cornifrons can be found on the East Coast and the Midwest (GBIF 2019b).