Family: Megachilidae
Subfamily: Megachilinae
Tribe: Anthidiini
Genus: Anthidium Fabricius, 1804
Subgenus: A. (Anthidium) Fabricius, 1804
Species: Anthidium utahense Swenk, 1914
Common name: none
Anthidium (Anthidium) utahense are dark brown to black, with light brown coloration on the tarsi, and yellow maculations (Gonzalez and Griswold 2013). Females have white pubescence except for some light ferruginous to yellow hairs on the vertex, scutum, axilla, scutellum, inner tarsi, and occasionally S6. Females range in body length from 6.2–10.3 mm, and males range in length from 8.5–10.8 mm (Gonzalez and Griswold 2013).
(modified from Gonzalez and Griswold 2013)
Anthidium utahense may be confused with A. jocosum based on the small body size; female basitarsi lacking dense tomentum; shape of the female T6; and shape of male T7, genitalia, and sterna (Gonzalez and Griswold 2013). Female A. utahense can be differentiated from A. jocosum by the broadly truncate apical margin T6 and yellow maculations on the clypeus and paraocular area (Gonzalez and Griswold 2013). Male A. utahense can also be differentiated from A. jocosum by the slightly more developed median apical brush on S4, and the more acute, dark, and sclerotized lateral lobe on S6 (Gonzalez and Griswold 2013).
Anthidium utahense adults have been recorded in flight from March to mid-September; however, one specimen was recorded in October. Peak activity occurs from May to July (Gonzalez and Griswold 2013).
Anthidium utahense is a generalist that has been observed visiting a variety of species within Alliaceae, Asteraceae, Boraginaceae, Brassicaceae, Cactaceae, Cleomaceae, Crassulaceae, Euphorbiaceae, Fabaceae, Fagaceae, Lamiaceae, Liliaceae, Malvaceae, Onagraceae, Plantaginaceae, Polemoniaceae, Polygonaceae, Portulacaceae, Rhamnaceae, Rosaceae, and Themidaceae (Gonzalez and Griswold 2013).
Anthidium utahense nests in holes or crevices in the ground. Each nest has between one and four cells that are comprised of plant trichomes from Cirsium and Artemisia. Nest plugs are constructed with pebbles (Jaycox 1966).
Anthidium utahense occur west of the Rocky Mountains in the U.S. (Gonzalez and Griswold 2013). In Mexico, they are found in Baja California. In Canada, they occur in southern British Columbia. They are found primarily in pine-oak forests, the Mojave and Sonoran deserts, California chaparral and woodlands, montane and coastal forests, shrub steppe, and grasslands. Anthidium utahense is very abundant in mediterranean California (Gonzalez and Griswold 2013).
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