Anthidium illustre

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Anthidiini
Genus: Anthidium Fabricius, 1804
Subgenus: A. (Anthidium) Fabricius, 1804
Species: Anthidium illustre Cresson, 1879
Common name: none

Overview

Anthidium (Anthidium) illustre are dark brown to black with yellow maculations (Gonzalez and Griswold 2013). Females have yellow to ferruginous pubescence, sometimes with white pubescence on the sides of the thorax, legs, tarsi, and abdomen. Females have a body length of 11.5–16.5 mm (Gonzalez and Griswold 2013). Males have dense, short, stout, simple, dark brown pubescence on the ventral surface of the hind coxa. Males range in body length from 14.6–18.5 mm (Gonzalez and Griswold 2013).

Diagnostic characteristics

(modified from Gonzalez and Griswold 2013)

  • Female labrum with preapical projections that curve upwards.
  • Female mandible with 6–8 teeth.
  • Female propodeal triangle is shiny and finely imbricate to lineolate.
  • Female hind tibia without anterior carina.
  • Female T1T5 discal areas are weakly elevated and weakly shiny.
  • Female T1T5 depressed marginal zones are dull with coarse and dense punctation.
  • Female T6 bilobed with distinct lateral spines.
  • Male S4 lacks a median apical brush, but the apical margin is distinctly concave with tufts of reddish-brown hair on the sides of the concavity.
  • Male S6 lateral lobes are obliquely truncate, and the median lobe is small and triangular.
  • Male S7 apical margin is pointed.
  • Male S8 apical margin is pointed, and the apex is laterally flattened and dorsally projected.
  • Male terga depressed marginal zone is densely punctate.
  • Male T6 lateral spine is straight and longer than T7 median spine.
  • Male T7 lateral lobe is curved with a convex outer and inner margin.

May be confused with

Anthidium illustre may be confused with A. formosum based on the large body size, female T6 apical margin with deep median emargination, and elongate male penis valves (Gonzalez and Griswold 2013). Anthidium illustre can be differentiated from A. formosum by the presence of preapical projections on the labrum (Gonzalez and Griswold 2013). Male A. illustre can also be differentiated from A. formosum by the shape of S4 and S6 (Gonzalez and Griswold 2013).

Phenology

Anthidium illustre adults have been recorded in flight from late February to August; however, two specimens were recorded in October. Peak activity occurs from May to July (Gonzalez and Griswold 2013).

Host associations

Anthidium illustre is a generalist that has been observed visiting a variety of species within Asteraceae, Boraginaceae, Fabaceae, Fumariaceae, Lamiaceae, Liliaceae, Malvaceae, Onagraceae, Orobanchaceae, Plantaginaceae, Polemoniaceae, Polygonaceae, and Themidaceae (Gonzalez and Griswold 2013).

Nesting behavior

Anthidium illustre nests in preexisting cavities. They have been observed nesting in the ground, inside abandoned nest tunnels of Anthophora occidentalis, inside beetle burrows, and in trap nests (Johnson 1904; Hicks 1929; Parker 1987). Beetle burrows were filled with dead Hesperoyucca whipplei stalks (Hicks 1929). Hicks (1929) also reported that females collect trichomes from Lepidospartum squamatum (Asteraceae) for their nests, and males exhibit territorial behaviors.

Distribution

Anthidium illustre occur throughout California, southern Oregon to southwestern Utah, and New Mexico in the U.S. (Gonzalez and Griswold 2013). In Mexico, they are found within Baja California. They are found primarily in scrub habitats and are absent in xeric ecosystems (Gonzalez and Griswold 2013).


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

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