Pseudoanthidium

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Anthidiini
Genus: Pseudoanthidium Friese, 1898
Subgenera: Branthidium, Exanthidium, Gnathanthidium, Immanthidium, Mesanthidiellum, Micranthidium, Neanthidium, Pseudoanthidium, Royanthidium, Semicarinella, Tuberanthidium, Zosteranthidium
Common name: none

Overview

Pseudoanthidium is a broad group with diverse species ranging from 6–11 mm in body length. Their color varies from having black integumentintegument:
a tough, protective outer layer
with distinct maculate bandsbands:
usually referring to bands of hair or bands of color that traverse across an abdominal segment
on the abdomen to being entirely black (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).

Diversity

Pseudoanthidium contains 64 species in 12 subgenera worldwide (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). One species, Pseudoanthidium nanum, has been introduced to the U.S.

Diagnostic characteristics

(modified from Litman et al. 2016Litman et al. 2016:
Litman, J.R., T.L. Griswold, and B.N. Danforth. 2016. Phylogenetic systematics and a revised generic classification of anthidiine bees (Hymenoptera: Megachilidae). Molecular Phylogenetics and Evolution 100: 183ndash;198. unless otherwise stated)

• Arolia absent.
• Hind tibiatibia:
  the segment of the leg, between the femur and the tarsus
  tuberculate (except Micranthidium, Immanthidium, and Zosteranthidium) (Litman et al. 2016Litman et al. 2016:
  Litman, J.R., T.L. Griswold, and B.N. Danforth. 2016. Phylogenetic systematics and a revised generic classification of anthidiine bees (Hymenoptera: Megachilidae). Molecular Phylogenetics and Evolution 100: 183ndash;198.).
• Juxtantennal carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  absent.
• Mandible mandible:
  bee teeth, so to speak, usually crossed and folded in front of the mouth
  with 4-9 teeth.
• Pronotal lobes carinatecarinate:
  having keels or carinae
  or lamellatelamellate:
  thin, plate-like, often somewhat translucent structure
  .
• Propodeum propodeum:
  the last segment of the thorax
  without foveafovea:
  a depressed region of cuticle; in bees this depressed area is usually only very slightly hollow and usually on the face.
  behind spiraclespiracle:
  a breathing pore, usually occurring on the third thorasic segment
  and without row of horizontal pits limited posteriorly by a distinct carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  .
• Punctures on tergaterga:
  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
  similar in diameter and density across entire surface (Litman et al. 2016Litman et al. 2016:
  Litman, J.R., T.L. Griswold, and B.N. Danforth. 2016. Phylogenetic systematics and a revised generic classification of anthidiine bees (Hymenoptera: Megachilidae). Molecular Phylogenetics and Evolution 100: 183ndash;198.).
• Scutellum scutellum:
  shield shaped plate behind scutum
  distinctly overhanging metanotummetanotum:
  the posterior dorsal segment of the thorax, behind the scutellum
  .
• Tarsal claws bifidbifid:
  divided into two branches; forked
  .
• Terga terga:
  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
  without a distinct apicalapical:
  near or at the apex or end of any structure
  depressed zone (Litman et al. 2016Litman et al. 2016:
  Litman, J.R., T.L. Griswold, and B.N. Danforth. 2016. Phylogenetic systematics and a revised generic classification of anthidiine bees (Hymenoptera: Megachilidae). Molecular Phylogenetics and Evolution 100: 183ndash;198.).

May be confused with

Pseudoanthidium and Afranthidium are very similar genera, with the multi-dentate mandibles in females and similar morphology. Recently several subgenera that were once considered part of the genus Afranthidium were placed in the genus Pseudoanthidium (Litman et al. 2016Litman et al. 2016:
Litman, J.R., T.L. Griswold, and B.N. Danforth. 2016. Phylogenetic systematics and a revised generic classification of anthidiine bees (Hymenoptera: Megachilidae). Molecular Phylogenetics and Evolution 100: 183ndash;198.). Pseudoanthidium differs from Afranthidium by the presence of strongly concave sternasterna:
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
with combs or specialized bristles (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).

Known invasives

Pseudoanthidium nanum is native to the western PalearcticPalearctic:
the largest biogeographic region; consists of Europe, Asia north of the Himalaya foothills, Northern Africa, and the northern and central parts of the Arabian Peninsula
region and has been found in the U.S. as early as 2008 in northern New Jersey. Since then, it has been collected in several states between Maryland and Massachusetts (Droege and Shapiro 2011Droege and Shapiro 2011:
Droege, S.W. and L.H. Shapiro. 2011. An August survey of wild bees (Hymenoptera: Apoidea) in the northeastern port areas of Baltimore, Maryland and the second North American record of Pseudoanthidium nanum (Mocsaacute;ry). The Maryland Entomologist 5: 33ndash;44.).

Pseudoanthidium repetitum is a potential invasive to the U.S. It is native to South Africa and has been introduced to and has established populations in Australia (Baumann et al. 2016Baumann et al. 2016:
Baumann, J.M., K. Walker, C. Threlfall, and N.S. Williams. 2016. African carder bee, Afranthidium (Immanthidium) repetitum Hymenoptera: Megachilidae): A new exotic species for Victoria. The Victorian Naturalist 133 (1), p.21.).

Host associations

Most Pseudoanthidium species are believed to be specialized on flowers in the family Asteraceae, although some may specialize on different tribes and subfamilies within Asteraceae (Müller 1996). There are, however, a few exceptions: P. ochragnathum is known to transition between families within Brassicaceae, Boraginaceae, and Fabaceae (Müller 1996). Pseudoanthidium (Immanthidium) has been seen on Fabaceae, and P. (Branthidium) has been observed visiting flowers in both Fabaceae and Asteraceae (Gess and Gess 2007Gess and Gess 2007:
Gess, S.K. and F.W. Gess. 2007. Notes on nesting and flower visiting of some anthidiine bees (Hymenoptera: Megachilidae: Megachilinae: Anthidiine) in southern Africa. Journal of Hymenoptera Research 16: 30ndash;50.).

Nesting behavior

Although nesting habits of most species are unknown, the nesting behavior of P. (Immanthidium) repetitum make it particularly capable of spreading outside its native range. Pseudoanthidium repetitum has been found nesting in electrical boxes, a heavy-duty vice, and electrical adaptors. Its ability to nest in man-made objects is likely how it was introduced to Australia in the 2000s, where it is now common in some areas (Baumann et al. 2016Baumann et al. 2016:
Baumann, J.M., K. Walker, C. Threlfall, and N.S. Williams. 2016. African carder bee, Afranthidium (Immanthidium) repetitum Hymenoptera: Megachilidae): A new exotic species for Victoria. The Victorian Naturalist 133 (1), p.21.).

Distribution

Pseudoanthidium are widespread across Africa, Europe, and Asia (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). Pseudoanthidium nanum has been introduced to the northeastern U.S. and Australia (Droege and Shapiro 2011Droege and Shapiro 2011:
Droege, S.W. and L.H. Shapiro. 2011. An August survey of wild bees (Hymenoptera: Apoidea) in the northeastern port areas of Baltimore, Maryland and the second North American record of Pseudoanthidium nanum (Mocsaacute;ry). The Maryland Entomologist 5: 33ndash;44.).

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

References

Baumann, J.M., K. Walker, C. Threlfall, and N.S. Williams. 2016. African Carder bee, Afranthidium (Immanthidium) repetitum'(Hymenoptera: Megachilidae): A new exotic species for Victoria. The Victorian Naturalist 133(1), p.21.

Droege, S.W. and L.H. Shapiro. 2011. An August survey of wild bees (Hymenoptera: Apoidea) in the northeastern port areas of Baltimore, Maryland and the second North American record of Pseudoanthidium nanum (Mocsáry). The Maryland Entomologist 5:33-44.

Gess, S.K. and F.W. Gess. 2007. Notes on nesting and flower visiting of some Anthidiine bees (Hymenoptera: Megachilidae: Megachilinae: Anthidiine) in Southern Africa. Journal of Hymenoptera Research 16:30–50. 

Litman, J.R., T.L. Griswold, and B.N. Danforth. 2016. Phylogenetic systematics and a revised generic classification of Anthidiine bees (Hymenoptera: Megachilidae). Molecular Phylogenetics and Evolution 100:183–198. 

Michener, C.D. 2007. The Bees of the World. 2nd. Ed. Johns Hopkins, Baltimore and London, 953 pp.

Müller, A. 1996. Host Plant Specialization in Western PalearcticPalearctic:
the largest biogeographic region; consists of Europe, Asia north of the Himalaya foothills, Northern Africa, and the northern and central parts of the Arabian Peninsula
Anthidiine Bees (Hymenoptera: Apoidea: Megachilidae). Ecological Monographs 66:235-257.