Anthidium atripes

Taxonomy

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

Overview

Anthidium (Anthidium) atripes have black integumentintegument:
a tough, protective outer layer
with cream or yellow-colored maculations (Gonzalez and Griswold 2013Gonzalez and Griswold 2013:
Gonzalez, V.H. and T.L. Griswold. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal 168: 221ndash;425.). Females have black pubescencepubescence:
short, fine hair
on their legs and white hairs on the fronsfrons:
the area between the antennae and ocelli on the bee's head
, vertexvertex:
the area between the ocelli and the back of the head
, pronotal lobepronotal lobe:
a part of the pronotum located dorsally on the posterior margin of the pronotum and overlaps the anterior thoracic spiracle
, scutumscutum:
the large segment on top of the thorax located between the wings and behind the head
, scutellumscutellum:
shield shaped plate behind scutum
, axillaaxilla:
the triangular or rounded point on the thorax where thoracic muscles meet the forewing of an insect
, and side of T1T1:
the segments on the top side of the abdomen, often abbreviated when referring to a specific segment to T1, T2, T3, T4, T5, T6, or T7
and T2T2:
the segments on the top side of the abdomen, often abbreviated when referring to a specific segment to T1, T2, T3, T4, T5, T6, or T7
. Females range in body length from 7.7–11.5 mm (Gonzalez and Griswold 2013Gonzalez and Griswold 2013:
Gonzalez, V.H. and T.L. Griswold. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal 168: 221ndash;425.). Males have black pubescencepubescence:
short, fine hair
on their genagena:
the cheek or side of the head
and legs, and white hairs on their head and thorax. Males range in body length from 10.8–14.5 mm (Gonzalez and Griswold 2013Gonzalez and Griswold 2013:
Gonzalez, V.H. and T.L. Griswold. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal 168: 221ndash;425.). Originally A. atripes was classified as a variety of Anthidium emarginatum (Schwarz 1928Schwarz 1928:
Schwarz, H.F. 1928. Bees of the subfamily Anthidiinae, including some new species and varieties, and some new locality records. Journal of the New York Entomological Society 36: 369ndash;419.).

Diagnostic characteristics

(modified from Gonzalez and Griswold 2013Gonzalez and Griswold 2013:
Gonzalez, V.H. and T.L. Griswold. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal 168: 221ndash;425.)

• Female clypeusclypeus:
  a section of the face below the antennae, demarcated by the epistomal sutures
  without hooked or curly hairs on discdisc:
  a generic term for the middle surface of a plate (usually in reference to an abdominal segment)
  .
• Female fore basitarsusbasitarsus:
  the segment of the tarsus that is the nearest to the body of the bee, usually the largest of all the tarsal segments
  is covered with short, semi-erect, unbranched hairs as well as dense, long tomentumtomentum:
  a form of pubescence composed of short matted, woolly hair
  , which cause the segment to appear robust.
• Female hind tibiatibia:
  the segment of the leg, between the femur and the tarsus
  without anterioranterior:
  toward the head or on the head side of a segment being described
  carina.
• Female labrumlabrum:
  part of the head abutting the clypeus, folds down in front of the mouthparts
  with two preapicalpreapical:
  referring to a section of a bee that is physically found just before the outermost (or apical) end of the section or segment
  projections and without basalbasal:
  originating at the foundation of a structure
  protuberances.
• Female mandiblemandible:
  bee teeth, so to speak, usually crossed and folded in front of the mouth
  with six teeth and without maculations.
• Female scopascopa:
  modified hairs for carrying pollen; often branched and dense hairs on the hind-leg, or on the ventral surface of the abdomen in Megachilidae
  dark brown to black.
• Female depressed marginal zones of T3–T5 are weakly punctatepunctate:
  studded with tiny holes
  and lack smooth, shiny distaldistal:
  place on a segment that is furthest from the place of attachment with the body
  margins.
• Female T5T5:
  the segments on the top side of the abdomen, often abbreviated when referring to a specific segment to T1, T2, T3, T4, T5, T6, or T7
  and T6T6:
  the segments on the top side of the abdomen, often abbreviated when referring to a specific segment to T1, T2, T3, T4, T5, T6, or T7
  lack maculations.
• Female T6T6:
  the segments on the top side of the abdomen, often abbreviated when referring to a specific segment to T1, T2, T3, T4, T5, T6, or T7
  with distaldistal:
  place on a segment that is furthest from the place of attachment with the body
  margin nearly truncatetruncate:
  ending abruptly, or squared off
  and apicalapical:
  near or at the apex or end of any structure
  rim depressed.
• Male S4S4:
  the plates on the underside of the abdomen, often abbreviated when referring to a specific segment to S1, S2, S3, S4, S5, S6, S7, or S8
  has a broad, black brush with a concave margin.
• Male S6S6:
  the plates on the underside of the abdomen, often abbreviated when referring to a specific segment to S1, S2, S3, S4, S5, S6, S7, or S8
  apexapex:
  end of any structure
  of median lobe is incised, and laterallateral:
  relating, pertaining, or attached to the side
  lobes are low or absent.
• Male S8S8:
  the plates on the underside of the abdomen, often abbreviated when referring to a specific segment to S1, S2, S3, S4, S5, S6, S7, or S8
  bifidbifid:
  divided into two branches; forked
  apicallyapically:
  near or at the apex or end of any structure
  .
• Male T7T7:
  the segments on the top side of the abdomen, often abbreviated when referring to a specific segment to T1, T2, T3, T4, T5, T6, or T7
  laterallateral:
  relating, pertaining, or attached to the side
  lobe is long and narrow.

May be confused with

Anthidium atripes may be confused with A. atripoides based on similar lengths, the depressed marginal zone of T3T3:
the segments on the top side of the abdomen, often abbreviated when referring to a specific segment to T1, T2, T3, T4, T5, T6, or T7
to T5T5:
the segments on the top side of the abdomen, often abbreviated when referring to a specific segment to T1, T2, T3, T4, T5, T6, or T7
with sparse punctationpunctation:
overall pattern of the punctures on a surface of a bee, includes size of punctures and the distance between them
, and a lack of smooth, shiny distaldistal:
place on a segment that is furthest from the place of attachment with the body
margins (Gonzalez and Griswold 2013Gonzalez and Griswold 2013:
Gonzalez, V.H. and T.L. Griswold. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal 168: 221ndash;425.). Female A. atripes can be differentiated from A. atripoides by the presence of dense, long tomentumtomentum:
a form of pubescence composed of short matted, woolly hair
on the mid and fore basitarsusbasitarsus:
the segment of the tarsus that is the nearest to the body of the bee, usually the largest of all the tarsal segments
and the thin apicalapical:
near or at the apex or end of any structure
margin of the clypeusclypeus:
a section of the face below the antennae, demarcated by the epistomal sutures
in A. atripes (Gonzalez and Griswold 2013Gonzalez and Griswold 2013:
Gonzalez, V.H. and T.L. Griswold. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal 168: 221ndash;425.). Male A. atripes can be differentiated from A. atripoides by the presence of a broad laterallateral:
relating, pertaining, or attached to the side
lobe on T7T7:
the segments on the top side of the abdomen, often abbreviated when referring to a specific segment to T1, T2, T3, T4, T5, T6, or T7
, a concave brush on the distaldistal:
place on a segment that is furthest from the place of attachment with the body
margin of S4S4:
the plates on the underside of the abdomen, often abbreviated when referring to a specific segment to S1, S2, S3, S4, S5, S6, S7, or S8
, and an incised apexapex:
end of any structure
on the median lobe of S6S6:
the plates on the underside of the abdomen, often abbreviated when referring to a specific segment to S1, S2, S3, S4, S5, S6, S7, or S8
in A. atripes (Gonzalez and Griswold 2013Gonzalez and Griswold 2013:
Gonzalez, V.H. and T.L. Griswold. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal 168: 221ndash;425.).

Phenology

Anthidium atripes adults have been recorded in flight from May to July; however, a single record was documented on three separate occasions in late August, mid-September, and early November. Peak activity occurs from the last half of May to early July (Gonzalez and Griswold 2013Gonzalez and Griswold 2013:
Gonzalez, V.H. and T.L. Griswold. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal 168: 221ndash;425.).

Host associations

Anthidium atripes is a generalist that has been observed visiting a variety of species of Asteraceae, Boraginaceae, Brassicaceae, Fabaceae, Malvaceae, Plantaginaceae, and Polemoniaceae (Gonzalez and Griswold 2013Gonzalez and Griswold 2013:
Gonzalez, V.H. and T.L. Griswold. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal 168: 221ndash;425.).

Nesting behavior

Nesting behavior is unknown.

Distribution

Anthidium atripes occur throughout the western U.S., from southern California along the northeastern side of the Sierra Nevada Mountains, to eastern Oregon, southern Idaho, western Colorado, and west Texas (Gonzalez and Griswold 2013Gonzalez and Griswold 2013:
Gonzalez, V.H. and T.L. Griswold. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal 168: 221ndash;425.). They are absent in Arizona and New Mexico. Anthidium atripes also occurs in Baja California, Mexico (Gonzalez and Griswold 2013Gonzalez and Griswold 2013:
Gonzalez, V.H. and T.L. Griswold. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal 168: 221ndash;425.). They are primarily found between 1,100–3,200 m in elevation within the Rocky Mountains, and are absent in desert and forest ecosystems (Gonzalez and Griswold 2013Gonzalez and Griswold 2013:
Gonzalez, V.H. and T.L. Griswold. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal 168: 221ndash;425.).

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References

Gonzalez, V.H. and T.L. Griswold. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal of the Linnean Society 168: 221-425.

Schwarz, H.F. 1928. Bees of the subfamily Anthidiinae, including some new species and varieties and some new locality records. Journal of the New York Entomological Society 36: 369-418.