Deposits on milkweed leaves and between leaf and stem.
Milkweed has several small black deposits on top surface of a few leaves, single deposits of same at joint between leaf and stem (top surface). Nothing on undersides of either. Milkweed beetles present. No sign of aphids. Deposit bear some resemblance to fecal deposit (maybe). Not shiny. About 1/8" long, half as wide. Both in groups and single deposit. Stationary. Not insect-like in appearance. Flowering, plant and leaf growth not affected. Plants tall and healthy. Currently supporting 2 monarch caterpillars.
Are monarch caterpillar droppings. Video on You Tube so demonstrating.