In addition to caterpillars, I’ve now had two Caribbean Milkweed Bugs (my gallery link) on my Milkweed flowers. There are several versions of this insect including a different subspecies in North America (Oncopeltus fasciatus) while the one here is Oncopeltus cingulifer. They do not harm the plant nor the caterpillars or butterflies if around. 🙂
GoogleAI says: “They use straw-like mouthparts to feed primarily on milkweed seeds and sap. By consuming milkweed, they store cardiac glycosides in their bodies, making them poisonous or unpalatable to predators like birds. They are mostly harmless to the plant and do not attack monarch butterfly eggs or caterpillars, meaning chemical control is rarely needed.”
One of my plants is seeding profusely, so maybe they were after the tiny seeds! 🙂
¡Pura Vida!