Inside: Has this noisy, fast, and aggressive summertime guest chased after you? Male woolcarder bees are a bit over-the-top assertive, but the females are superb pollinators and fun to watch.
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Female woolcarder bees collect fibers by “carding”—or scraping—them from a plant surface. She wads the fibers into a ball, tucks the ball under her body, and carries it back to her nest. Once home, she lines her nest with the fibers, making a nice cushy spot to raise her young.
Audacious, aggressive, and quick
These large and noisy bees in the genus Anthidium appear in early summer. You can often see the males jealously guarding a patch of flowers. The males aggressively fend off any interlopers by darting and chasing. If necessary, he will wrestle a competitor to the ground—even bees much larger than himself, such as bumble bees and honey bees.
The only bees allowed inside his territory—female woolcarder bees—can enter and forage in return for the chance to mate.
North America has more than one species
The native species in North America is Anthidium maculosum. The bees are small, measuring one-half to three-quarters of an inch long. They are black to brown with white or yellow patches on their abdomens. The female carries pollen on the underside of her abdomen in a patch of hairs called a scopa.
A similar species, Anthidium manicatum, came from northern Europe and has spread across the continent. The male of this species is even more aggressive and is reported to actually kill bees competing for his territory.
Woolcarder bees are summertime pollinators
You can expect to see woolcarder bees in early summer. They will readily use nesting blocks with holes drilled 7-10 mm in diameter. Favorite forage includes sage, mint, catnip, lavender, Russian sage, and hedgenettle (Stachys).
As a general rule, bees are difficult to identify down to the species level, but with a little practice, you can become quite competent at the genus level. The woolcarder bees are a good group to start with because both their behavior and their coloring are striking.
Honey Bee Suite