Anthidium tenuiflorae

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Anthidiini
Genus: Anthidium Fabricius, 1804
Subgenus: A. (Anthidium) Fabricius, 1804
Species: Anthidium tenuiflorae Cockerell, 1907
Common name: none

Overview

Anthidium (Anthidium) tenuiflorae are dark brown to black, with light brown coloration on the tarsi, and ivory or yellow maculations (Gonzalez and Griswold 2013). Females have white or yellow pubescence except for darker hairs on the inner tarsi and center of the sternal scopa. The fore and mid basitarsi are covered by dense tomentum. Females have a body length of 8.0–9.3 mm, and males range in body length from 8.9–13.1 mm (Gonzalez and Griswold 2013).

Diagnostic characteristics

(modified from Gonzalez and Griswold 2013)

  • Female labrum has large, curved preapical projections but lacks basal protuberances.
  • Female mandible has six teeth.
  • Female propodeal triangle is weakly shiny and finely imbricate.
  • Female hind tibia without anterior carina.
  • Female T1T5 discal areas are weakly elevated with weakly imbricate to lineolate areas between smooth, shiny punctures.
  • Female T1T5 depressed marginal zones have small, coarse, dense punctures.
  • Female T1T5 impunctate apical areas are narrow with a smooth, shiny border.
  • Female T6 lacks a preapical carina and median emargination.
  • Male labrum preapical projections are longer than that in females.
  • Male S4 with median apical brush of long, black hairs along one-third of the margin.
  • Male S4 apical margin is slightly concave medially.
  • Male S6 acute lateral lobes with slightly concave outer margins and a broadly rounded median lobe.
  • Male S7 is apically pointed.
  • Male S8 has a broad, apically bifid apical process with ventrally pointed lobes.
  • Male T6 lateral spine is straight and about as long as T7 median spine.
  • Male T7 lateral lobe is broad, apically rounded, and about 1.5 times broader than the distance between the inner margin and median spine.

May be confused with

Female A. tenuiflorae can be differentiated from other Anthidium species by the combination of pale sternal scopa, distinctly shiny terga, and T6 broadly truncate without a distinct median emargination (Gonzalez and Griswold 2013). Male A. tenuiflorae may be confused with A. emarginatum and A. platyfrons by the broadly rounded lateral lobe of T7, and S4 with an apical brush of long, black hairs. Male A. tenuiflorae can be differentiated from these two species by the narrow, acute lateral lobe of S6 with a concave outer margin and a long, narrow apical process of S8 (Gonzalez and Griswold 2013).

Phenology

Anthidium tenuiflorae adults have been recorded in flight from March to September; however, a single specimen was recorded in November. Peak activity occurs from June to August (Gonzalez and Griswold 2013).

Host associations

Anthidium tenuiflorae is a generalist that has been observed visiting a variety of species within Alliaceae, Asteraceae, Boraginaceae, Brassicaceae, Caryophyllaceae, Crassulaceae, Fabaceae, Lamiaceae, Onagraceae, Plantaginaceae, and Rosaceae (Gonzalez and Griswold 2013).

Nesting behavior

Anthidium tenuiflorae may nest in holes in the ground. Nest plugs are comprised of pebbles (Hicks 1926).

Distribution

Anthidium tenuiflorae are thought to be the most widespread species of Anthidium in North America. They occur in the U.S. in California, Arizona, northern New Mexico, Montana, North Dakota, Minnesota, Alaska, Colorado, and Washington (Gonzalez and Griswold 2013). In Mexico, they occur in Baja California. In Canada, they are found in British Columbia, Yukon, Alberta, and Saskatchewan (Gonzalez and Griswold 2013). They are found primarily in pine-oak forests, montane chaparral, woodlands, forests, shrub steppe, grasslands, and tundras, but are absent in deserts (Gonzalez and Griswold 2013).


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

<p><em>Anthidium tenuiflorae</em> female face, photo: Chelsey Ritner</p>
Anthidium tenuiflorae female face, photo: Chelsey Ritner
<p><em>Anthidium tenuiflorae</em> female lateral habitus, photo: Chelsey Ritner</p>
Anthidium tenuiflorae female lateral habitus, photo: Chelsey Ritner
<p><em>Anthidium tenuiflorae</em> female abdomen, photo: Chelsey Ritner</p>
Anthidium tenuiflorae female abdomen, photo: Chelsey Ritner
<p><em>Anthidium tenuiflorae</em> female, diagram showing the dorsal view of the sixth tergite (T6), diagram from Gonzalez and Griswold 2013</p>
Anthidium tenuiflorae female, diagram showing the dorsal view of the sixth tergite (T6), diagram from Gonzalez and Griswold 2013
<p><em>Anthidium tenuiflorae</em> male face, photo: Chelsey Ritner</p>
Anthidium tenuiflorae male face, photo: Chelsey Ritner
<p><em>Anthidium tenuiflorae</em> male lateral habitus, photo: Chelsey Ritner</p>
Anthidium tenuiflorae male lateral habitus, photo: Chelsey Ritner
<p><em>Anthidium tenuiflorae</em> male abdomen, photo: Chelsey Ritner</p>
Anthidium tenuiflorae male abdomen, photo: Chelsey Ritner
<p><em>Anthidium tenuiflorae</em> male, ventral view of fourth sternum (S4), photo from Gonzalez and Griswold 2013</p>
Anthidium tenuiflorae male, ventral view of fourth sternum (S4), photo from Gonzalez and Griswold 2013
<p><em>Anthidium tenuiflorae</em> male, dorsal view of seventh tergum (T7), photo: Chelsey Ritner</p>
Anthidium tenuiflorae male, dorsal view of seventh tergum (T7), photo: Chelsey Ritner
<p><em>Anthidium tenuiflorae</em> male, diagram showing dorsal view of seventh tergum (T7), diagram from Gonzalez and Griswold 2013</p>
Anthidium tenuiflorae male, diagram showing dorsal view of seventh tergum (T7), diagram from Gonzalez and Griswold 2013
<p><em>Anthidium tenuiflorae</em> male, diagram showing ventral view of sixth sternum (S6), diagram from Gonzalez and Griswold 2013</p>
Anthidium tenuiflorae male, diagram showing ventral view of sixth sternum (S6), diagram from Gonzalez and Griswold 2013
<p><em>Anthidium tenuiflorae</em> male, diagram showing ventral view of seventh sternum (S7), diagram from Gonzalez and Griswold 2013</p>
Anthidium tenuiflorae male, diagram showing ventral view of seventh sternum (S7), diagram from Gonzalez and Griswold 2013
<p><em>Anthidium tenuiflorae</em> male, diagram showing ventral view of eighth sternum (S8), diagram from Gonzalez and Griswold 2013</p>
Anthidium tenuiflorae male, diagram showing ventral view of eighth sternum (S8), diagram from Gonzalez and Griswold 2013