Genus: Anthidium Fabricius, 1804
Subgenus: Proanthidium Friese, 1898
Common name: none
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).
(modified from Michener 2007)
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).
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).
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).
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).