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 integument with distinct maculate bands on the abdomen to being entirely black (Michener 2007).

Diversity

Pseudoanthidium contains 64 species in 12 subgenera worldwide (Michener 2007). One species, Pseudoanthidium nanum, has been introduced to the U.S.

Diagnostic characteristics

(modified from Litman et al. 2016 unless otherwise stated)

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. 2016). Pseudoanthidium differs from Afranthidium by the presence of strongly concave sterna with combs or specialized bristles (Michener 2007).

Known invasives

Pseudoanthidium nanum is native to the western Palearctic 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 2011).

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. 2016).

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 2007).

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. 2016).

Distribution

Pseudoanthidium are widespread across Africa, Europe, and Asia (Michener 2007). Pseudoanthidium nanum has been introduced to the northeastern U.S. and Australia (Droege and Shapiro 2011).
Pseudoanthidium" target="_blank">Pseudoanthidium&r=.2&m_symbol_edge=black" style="width:720px" />
​Distribution map generated by Pseudoanthidium" target="_blank">Discover Life -- click on map for details, credits, and terms of use.

<p><em>Pseudoanthidium truncatum </em>female face, photo: C. Ritner</p>
Pseudoanthidium truncatum female face, photo: C. Ritner
<p><em>Pseudoanthidium truncatum</em> female lateral habitus, photo: C. Ritner</p>
Pseudoanthidium truncatum female lateral habitus, photo: C. Ritner
<p><em>Pseudoanthidium truncatum </em>female abdomen, photo: T. Brady</p>
Pseudoanthidium truncatum female abdomen, photo: T. Brady
<p><em>Pseudoanthidium augustifrons</em> male face, photo: C. Ritner</p>
Pseudoanthidium augustifrons male face, photo: C. Ritner
<p><em>Pseudoanthidium augustifrons</em> male lateral habitus, photo: C. Ritner</p>
Pseudoanthidium augustifrons male lateral habitus, photo: C. Ritner
<p><em>Pseudoanthidium truncatum</em> male abdomen, photo: T. Brady</p>
Pseudoanthidium truncatum male abdomen, photo: T. Brady
<p><em>Pseudoanthidium meximium</em> female T6 apical margin with emarginate projection, photo: C. Ritner</p>
Pseudoanthidium meximium female T6 apical margin with emarginate projection, photo: C. Ritner
<p><em>Pseudoanthidium meximium</em> male T7 at least half as wide as T6, photo: C. Ritner</p>
Pseudoanthidium meximium male T7 at least half as wide as T6, photo: C. Ritner
<p><em>Pseudoanthidium wahrmannicum </em>male T7 bilobed and medially emarginate, photo: C. Ritner</p>
Pseudoanthidium wahrmannicum male T7 bilobed and medially emarginate, photo: C. Ritner
<p><em>Pseudoanthidium truncatum</em> male S3 with comb, photo: C. Ritner</p>
Pseudoanthidium truncatum male S3 with comb, photo: C. Ritner
<p><em>Pseudoanthidium truncatum</em> male S5 with lobed combs, photo: C. Ritner</p>
Pseudoanthidium truncatum male S5 with lobed combs, photo: C. Ritner