Anthidium (Proanthidium)

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Anthidiini
Genus: Anthidium Fabricius, 1804
Subgenus: Proanthidium Friese, 1898
Common name: none

Overview

Anthidium (Proanthidium) are black bees with yellow markings and abdominal bands that are typically broken, but lack an emargination (Michener 2007). They range in body length from 7–12 mm (Michener 2007). One species, A. oblongatum, is invasive in the U.S. and Canada. This species is of special interest because it is the first species of Anthidium to be documented entering the nest of a social Hymenoptera, Bombus impatiens (Graham 2018). The night temperatures leading up to the discovery of A. oblongatum in B. impatiens hives were uncharacteristically low, so it is possible that the A. oblongatum specimens were attempting to find a warm place to reside at night (Graham 2018). However, if A. oblongatum were inside the hive in order to rob resources, this would cause a negative impact on the native bee population. More research is needed in order to determine the motivation behind the nest intrusion (Graham 2018).

Diagnostic characteristics

(modified from Michener 2007)

May be confused with

Anthidium (Proanthidium) may be confused with bees in the genus Dianthidium due to similar body morphology (Michener 2007). Some A. (Proanthidium) may also be confused with bees in the genus Pseudoanthidium due to the presence of a laterally carinate scutellum, with the production of a tooth or angle near the axilla, and the presence of a concave T6 (Michener 2007). However, A. (Proanthidium) can be differentiated from Dianthidium and Pseudoanthidium due to the distinguishing characteristics listed above as well as the generic characters (Michener 2007).

Host associations

Anthidium (Proanthidium) are mostly generalists (Müller 1996). Anthidium rotundum has a preference for thistles (Cardueae), while A. undulatum has a preference for Fabaceae and Lamiaceae (Müller 1996; Khodaparast and Monfared 2012).

Nesting behavior

Anthidium oblongatum nests in preexisting cavities. Cell partitions are comprised of a cottony plant down (O’Brien et al. 2012; Onuferko et al. 2015; Discover Life 2018).

Diversity

Anthidium (Proanthidium) consists of eight species, one of which (A. oblongatum) is invasive in the U.S. and Canada (Michener 2007).

Known invasives

Anthidium oblongatum is the only known invasive, and was accidentally introduced from Europe in the 1990s (Russo 2016). The species has since spread throughout the eastern U.S. and southern Canada (Hoebeke and Wheeler 1999; Miller et al. 2002; Romankova 2003; Michener 2007; Maier 2009; Tonietto and Ascher 2009).

Distribution

Anthidium (Proanthidium) occur from Portugal through the Mediterranean Basin, north to Europe, and east through Asia (Michener 2007). One species, A. oblongatum, which is invasive to the U.S., occurs in the eastern U.S. in Maryland, New York, New Jersey, Pennsylvania, Ohio, Illinois, and Connecticut, and southern Canada (Hoebeke and Wheeler 1999; Miller et al. 2002; Romankova 2003; Michener 2007; Maier 2009; Tonietto and Ascher 2009).


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

<p>Fig 1, <em>Anthidium amabile</em> male face, photo: Chelsey Ritner</p>
Fig 1, Anthidium amabile male face, photo: Chelsey Ritner
<p>Fig 2, <em>Anthidium amabile</em> male lateral habitus, photo: Chelsey Ritner</p>
Fig 2, Anthidium amabile male lateral habitus, photo: Chelsey Ritner
<p>Fig 3, <em>Anthidium amabile</em> male abdomen, photo: Chelsey Ritner</p>
Fig 3, Anthidium amabile male abdomen, photo: Chelsey Ritner