Anthidium formosum

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Anthidiini
Genus: Anthidium Fabricius, 1804
Subgenus: A. (Anthidium) Fabricius, 1804
Species: Anthidium formosum Cresson, 1878
Common name: none

Overview

Anthidium (Anthidium) formosum are dark brown to black with yellow 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 yellow to ferruginousferruginous:
rust-colored
pubescence, sometimes with white pubescencepubescence:
short, fine hair
on the sides of the thorax and abdomen, and have a body length of 11.5–13.5 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 white pubescencepubescence:
short, fine hair
on their head and thorax, and range in length from 12.8–15.4 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.).

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.)

• Labrum labrum:
  part of the head abutting the clypeus, folds down in front of the mouthparts
  lacks basalbasal:
  originating at the foundation of a structure
  protruberances and 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.
• Female mandiblemandible:
  bee teeth, so to speak, usually crossed and folded in front of the mouth
  has six teeth.
• Female propodealpropodeal:
  the last segment of the thorax
  triangle is shiny and finely imbricateimbricate:
  overlapping, like shingles or roof tiles
  to lineolatelineolate:
  marked with fine lines
  .
• 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 T1–T5 depressed marginal zones are dull, and coarsely and densely punctatepunctate:
  studded with tiny holes
  .
• Female T1–T5 discal areas are weakly elevated and weakly shiny.
• Female T1–T5 distaldistal:
  place on a segment that is furthest from the place of attachment with the body
  margins are narrow.
• 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
  distaldistal:
  place on a segment that is furthest from the place of attachment with the body
  margin is medially projected with a deep emarginationemargination:
  a notched or cut out place in an edge or margin, can be dramatic or simply a subtle inward departure from the general curve or line of the margin or structure being described
  .
• 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
  is elevated along the midline with a small, distinct laterallateral:
  relating, pertaining, or attached to the side
  spine.
• 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
  preapicalpreapical:
  referring to a section of a bee that is physically found just before the outermost (or apical) end of the section or segment
  carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  and depressed apicalapical:
  near or at the apex or end of any structure
  rim is absent.
• 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 reddish-brown brush of long apicalapical:
  near or at the apex or end of any structure
  hairs on a concave distaldistal:
  place on a segment that is furthest from the place of attachment with the body
  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
  basalbasal:
  originating at the foundation of a structure
  margin is bilobed.
• 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
  laterallateral:
  relating, pertaining, or attached to the side
  lobes are subquadrate and median lobe is absent.
• Male S7S7:
  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
  is apicallyapically:
  near or at the apex or end of any structure
  narrow.
• 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
  apicalapical:
  near or at the apex or end of any structure
  process is laterally flattened.
• Male 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
  laterallateral:
  relating, pertaining, or attached to the side
  spine is straight, and longer than 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
  median spine.
• 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 apicallyapically:
  near or at the apex or end of any structure
  subtriangular with a convexconvex:
  curved outward
  outer margin and concave inner margin.

May be confused with

Anthidium formosum may be confused with A. illustre based on the large body size, 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
distaldistal:
place on a segment that is furthest from the place of attachment with the body
margin with a deep median emarginationemargination:
a notched or cut out place in an edge or margin, can be dramatic or simply a subtle inward departure from the general curve or line of the margin or structure being described
, and elongate male penis valves (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.). Both sexes of Anthidium formosum can be differentiated from A. illustre by the lack of 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 on the labrumlabrum:
part of the head abutting the clypeus, folds down in front of the mouthparts
(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. formosum can also be differentiated from A. illustre by the shape 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 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
(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 formosum adults have been recorded in flight from May to September, with peak activity occurring from the last half of June to the first half of August (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 formosum is a generalist that has been observed visiting a variety of species within Asteraceae, Boraginaceae, Fabaceae, Lamiaceae, Orobanchaceae, and Ranunculaceae (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

Anthidium formosum nesting biology was determined from trap nests (Horning 1969Horning 1969:
Horning, D.S. 1969. First recorded occurrence of the genus Callanthidium in Idaho with notes on three nests of C. formosum (Cresson) (Hymenoptera: Megachilidae). The Pan-Pacific Entomologist 45: 239.; Parker 1987Parker 1987:
Parker, F.D. 1987. Nests of Callanthidium from block traps (Hymenoptera: Megachilidae). The Pan-Pacific Entomologist 63: 125ndash;129.). Nests plugs are constructed out of a variety of materials, ranging from only trichomes to trichomes with pebbles, small pieces of wood, masticated plant material, or lizard dung (Krombein 1967Krombein 1967:
Krombein, K.V. 1967. Trap nesting wasp and bees: life histories, nests, and associates. Washington, DC: Smithsonian Press.). Horning (1969) also observed resin in the nest plugs of three A. formosum nests in Idaho.

Distribution

Anthidium formosum occur throughout California, Oregon, Washington, Montana, Wyoming, and Colorado. They are found primarily in the Great Basin, Snake-Columbia, and Wyoming Basin shrub steppe; Colorado Plateau shrublands; Wasatch, Uinta, and Great Basin montane forests; and eastern Cascades and Sierra Nevada forests (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.

Horning, D.S. 1969. First recorded occurrence of the genus Callanthidium in Idaho with notes on three nests of C. formosum (Cresson) (Hymenoptera: Megachilidae). The Pan-Pacific Entomologist 45: 239.

Krombein K.V. 1967. Trap nesting wasp and bees: life histories, nests and associates. Washington, DC: Smithsonian Press, iii-ivi. 570 pp.

Parker, F.D. 1987. Nests of Callanthidium from block traps (Hymenoptera: Megachilidae). The Pan-Pacific Entomologist 63: 125-129.