These are exactly what they eat: milkweed beetles. A couple of years ago they totally stripped my A. tuberosa and A. curassavica. If you look closely at the plant, you'll see the grub larvae all over it at various ages. It is NOT beneficial to your plant. They don't even acquire the toxins that Monarch butterflies do from the plant, so scientists believe that the orange is just a bluff to preditors to keep from being eaten.
They are the same insect...the spots vary, as well as the color. The correct common names are Milkweed Leaf Beetle or Swamp Milkweed Leaf Beetle. Mine were more yellow, but the spots varied from the X to a big blotch on the back.