Adult polyphemus moths are large and butterfly-like. The ground color varies greatly; some specimens are brown or tan, others are bright reddish brown. All have a small eyespot in the center of the forewing, and a very large eyespot in the middle of the hindwing. Males have smaller bodies than females, and their plumelike antennae are larger than those of females.
Larvae are bright translucent green, with convex (ballooned-out) segments. There are yellowish-red tubercles on the thoracic and abdominal segments, with those in the dorsal (top) area having a metallic luster. The head is brown.
Wingspan: 3½–5½ inches. This is the second largest moth in Missouri.
Habitat and Conservation
Polyphemus moths can be abundant in and near forests, also in parks and suburban areas, orchards, and wetlands. Adults are frequently attracted to lights at night. Populations of this and other giant silk moths are harmed by parasitic flies and wasps that were intentionally introduced into North America to prey on the invasive spongy moth. While many species introduced for biological control prey on only a single or a few related species, several generalist predators have been introduced to the detriment of native species.
Larvae feed on more than 20 species of trees and shrubs in Missouri. Among the favorites are silver maple, birch, hazelnut, and oak. Adults do not eat at all and only survive a few weeks at most.
Multibrooded resident. Some populations are declining (see "Habitat and Conservation" above).
Adults fly from mid-April through August. A multibrooded species in Missouri. Adults are nocturnal and seek mates between about 11 p.m. and 1 a.m. Cocoons are oval, usually wrapped in a leaf of the food plant, with a tough outer layer of silk. They usually fall to the ground in the autumn when the food plant drops its leaves. Sometimes they are attached to stems and persist there through the winter.
The polyphemus is named after the giant one-eyed monster (cyclops) of Homer’s Odyssey, for the big eyespot on each hindwing.
Insect collecting, especially butterfly and moth collecting, is popular in large part because of the striking beauty of the specimens collected. It’s a global industry, with killed and mounted specimens marketed and shipped worldwide.
The caterpillars are herbivores that graze on vegetation. The adults serve a role in pollination. All stages provide food for predators. Caterpillars of many moths can be parasitized by wasps, which lay eggs directly on the caterpillars, eventually killing them.