Swamp Milkweed

Notes:

The flowers are very popular with many kinds of insects, including bumblebees, honeybees, long-horned bees (Melissodes spp., Svastra spp.), Halictid bees, Sphecid wasps, Vespid wasps, Tiphiid wasps, Spider wasps, Mydas flies, thick-headed flies, Tachinid flies, Swallowtail butterflies, Greater Fritillaries, Monarch butterflies, and skippers. Another occasional visitor of the flowers is the Ruby-Throated Hummingbird. All of these visitors seek nectar. Some insects feed destructively on the foliage and other parts of Swamp Milkweed and other Asclepias spp. (milkweeds). These insect feeders include caterpillars of the butterfly Danaus plexippes (Monarch), Labidomera clavicollis (Swamp Milkweed Leaf Beetle), Oncopeltus fasciatus (Large Milkweed Bug), and Aphis nerii (Yellow Milkweed Aphid). The latter aphid often congregates on the upper stems and young leaves. Mammalian herbivores leave this plant alone because the foliage is both bitter and toxic, containing cardiac glycosides.