The nectar of the flowers attracts long-tongued bees, Sphecid wasps, and various butterflies, including Swallowtails and Fritillaries. The Ruby-Throated Hummingbird also seeks nectar from the flowers. The caterpillars of Danaus plexippes (Monarch Butterfly) consume the foliage. This plant also attracts other insects, some of which feed exclusively on milkweeds and their relatives. (see Insect Table for more information). Mammalian herbivores avoid this and other milkweeds because of the bitterness and toxicity of their leaves.