If I were giving out an award for the most social flower of the year, black-eyed susan would win. One fun day, I spent the morning checking and rechecking on them, noticing and admiring the diversity of insects that were attracted to the blossoms. About two-thirds of these photos are from that one day alone.
Bees:
Flies:
Flies that look like bees:
Butterflies:
Bees and butterflies:
Lacewing:
Aphids:
Beetle:
Japanese beetle doing the splits:
Leafhopper:
I don’t know what this is:
Inchworm:
And my favorite find, a camouflaged looper inchworm:
(More about this camouflaged looper caterpillar.)
There was also this gruesome find — one dead bee on a petal, with two dead bees and one dead fly suspended below — but then again, a spider’s gotta eat, too. (I assume that’s what created this scene.)
crystallofolia 
Wow, I never seem to see many pollinators on Rudbeckia… but maybe it’s because I mostly have R. subtomentosa. Do you see them on that species also? Not totally sure if any of these photos were R. sub… maybe the last one was?
Hmm. What I’ve been calling my “black-eyed susan cultivar” might be R. subtomentosa, so thanks for that suggestion. I seem to be going down a rabbit hole trying to identify it right now; may need to write another post about my native orange coneflower vs. what I call my “black-eyed susan cultivar” (which visually looks like the same plant – R. fulgida). Wish I would have kept better records at the beginning of my gardening!
Anyway. None of these photos are from those plants. I rarely see insects on them.
Most of the photos in this post are of R. hirta, though that patch of flowers is mingling with what I think are the “gloriosa daisy” variety of R. hirta (that name is an assumption; they’re the ones with petals that are darker near the centers), and it was hard to tell which was which when they were all blooming.