Milkweeds in a field

Milkweed in a field. Common Milkweed is an important plant because so many species of insects depend on it. Monarch Butterflies, Milkweed Bugs, and Milkweed Leaf Beetles only eat milkweed, and could not survive without it. Many other species of insects use milkweed as their primary food source, or as a major food source.