Osmia excavata

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Osmiini
Genus: Osmia Panzer, 1806
Subgenus: O. (Osmia) Panzer, 1806
Species: Osmia excavata Alfken, 1903
Common name: none

Overview

Osmia (Osmia) excavata are black bees with a green luster to their abdomen (Wei et al. 2002). Females have intermixed white and black hair on the head and thorax, yellow to black hair on the discs of T1T6, and pale apical hair bands on the terga (Wu 2006). Female length ranges between 9–13 mm, and male body length ranges between 8–10 mm. (Wei et al. 2002; Wu 2006). O. excavata is an important fruit tree pollinator in Japan and is considered an ideal species for apple pollination (Wei et al. 2002).

Diagnostic characteristics 

(modified from Wu 2006)

May be confused with 

Female Osmia excavata are most similar to O. fedtschenkoi because of the deep triangular-shaped emargination on the clypeus. The emargination of O. excavata, however, continues into the disc of the clypeus, creating a shiny-bottomed concavity which differs from the more simple triangular emargination of O. fedtschenkoi. Male O. excavata can look very similar to O. longicornis, but they can be distinguished by the lack of a distinct median emargination on the apical rim of the clypeus of O. excavata as well as by the shape of the gonocoxites.

Phenology

Osmia excavata adults have been recorded in flight from late March to early April (Wei et al. 2002).

Host associations 

Osmia excavata appear to prefer plants from the Rosaceae family (Wei et al. 2002).

Nesting behavior 

Osmia excavata nests in preexisting cavities, typically in insect borings in dead wood, as well as in hollow plants, stems of bamboo, and straw tubes. Cell wall, partitions, and nest plug are composed of mud or leaf materials (Maeta 1978).

Distribution

Osmia excavata specimens have been recorded in Beijing, Hebei, Liaoning, Shanghai, Jiangsu, and Shandong in China, as well as in Japan and the North Korean peninsula (Wu 2006).


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

<p><em>Osmia excavata</em> female face, photo: Chelsey Ritner</p>
Osmia excavata female face, photo: Chelsey Ritner
<p><em>Osmia excavata </em>female lateral habitus, photo: Chelsey Ritner</p>
Osmia excavata female lateral habitus, photo: Chelsey Ritner
<p><em>Osmia excavata</em> female abdomen, photo: Chelsey Ritner</p>
Osmia excavata female abdomen, photo: Chelsey Ritner
<p><em>Osmia excavata </em>male face, photo: Chelsey Ritner</p>
Osmia excavata male face, photo: Chelsey Ritner
<p><em>Osmia excavata</em> male lateral habitus, photo: Chelsey Ritner</p>
Osmia excavata male lateral habitus, photo: Chelsey Ritner
<p><em>Osmia excavata</em> male abdomen, photo: Chelsey Ritner</p>
Osmia excavata male abdomen, photo: Chelsey Ritner
<p><em>Osmia excavata </em>male, dorsal view of seventh tergum (T7), photo: Chelsey Ritner</p>
Osmia excavata male, dorsal view of seventh tergum (T7), photo: Chelsey Ritner
<p><em>Osmia excavata</em> male, diagram showing dorsal view of genitalia, diagram modified from Wu 2006</p>
Osmia excavata male, diagram showing dorsal view of genitalia, diagram modified from Wu 2006