Dry, dusty fields with weedy legumes offer a good chance of finding northern rotund resin bees (Anthidiellum notatum). Although scarce throughout the region, this tiny black-and-yellow anthiidine can be locally abundant, provided suitable legumes are in flower (exotic weedy legumes are perfectly acceptable). This distinctive bee is unlikely to be confused with many other species in the region with its dark eyes and distinctive “staccato” patterning on abdomen.
Active in mid-summer from June through August. One flight period per year.
Widespread throughout region, from Maryland north to Quebec.
Size << honey bee
Males and females are similar in size and appearance. Compact and pill-shaped. Rough black integument painted strongly with yellow markings on thorax and face. Broken yellow band across T2 and much shorter “staccato” markings across T3-5. Smoky-dark wings often held out while foraging.
- Anthidium oblongatum, which also likes weedy legumes, has green eyes, orange tegulae, and long (slightly broken) yellow bands on abdomen
- Paranthidium jugatorium has long (slightly broken) yellow bands on abdomen and strong preference for yellow “sunflower” composites.
Nests above-ground, singly. Fashions single-brood cell nest “jugs” entirely out of resin, suspending them from branches.
Strong preference for small-flowered legumes like yellow wild indigo (Baptisia tinctoria), bush-clover (Lespedeza), and birds-foot trefoil (Lotus corniculatus). Known to also nectar on knapweed (Knautia) and possibly other asters. Mating often occurs on flowers, and can last for minutes at a time.
No known cleptoparasites for this species.
Page last updated:
January 17, 2023