On adult luna moths, the overall color is a pale or lime green, with a dark leading edge on the forewings, and a long, tapering tail on the hindwings; each of the four wings has an eyespot. The antennae, particularly on males, are feathery.
Larvae are bright green caterpillars, the segments convex (expanded outward) with narrow yellow bands positioned at the hind part of each segment; a yellowish lateral (side) stripe runs below the spiracles (small holes that allow air into respiratory organs), and three lateral rows of reddish tubercles on each side; the head is brownish.
Similar species: The caterpillar of the polyphemus moth looks quite similar, but it has the yellow bands running nearly across the spiracles, about at the center of each segment, instead of at the back edge of each segment.
Wingspan: 3–4¼ inches; larvae can grow up to 3½ inches long.
Habitat and Conservation
Luna moths are usually found in and near deciduous woodlands, where their larval food plants occur: walnut, hickory, persimmon, and sweet gum. In some areas, populations have declined due to habitat destruction and increased use of bright lights at night, which can disrupt mating cycles.
Luna moth caterpillars eat the foliage of walnuts, hickories, pecan, persimmon, sweet gum, and sumacs. Adults, like other members of the giant silkworm family, have reduced mouthparts, so they don’t eat at all. Thus, the adults only live for about a week.
Common throughout the state.
Eggs incubate for 8–13 days before hatching. The caterpillars feed and grow larger, then pupate in a thin, silken cocoon spun among leaf litter on the ground, and emerge as winged adults. There are three broods in Missouri, with adults flying from early April through August. Around midnight, females “call” males by emitting pheromones, which the male’s highly sensitive, featherlike antennae can pick up. As with other members of this family, the winged adults don't live very long, as they cannot eat, surviving on the food they ate as caterpillars. They only exist long enough to mate and produce eggs.
Luna moths are often used in classrooms to teach insect life cycles.
The beauty of luna moths is appreciated by anyone who is lucky enough to spot them.
People who collect butterflies and moths consider these breathtakingly beautiful moths some of their prized specimens.
The name "luna" means "moon," and it is the root of the words "lunar" and "lunatic" (a term that arose back when people thought the moon could have a harmful effect on human mentality). "Luna" originated as the name of a Roman moon goddess; the Greek equivalent was the goddess Selene.
If you're interested in moths, look for Gene Stratton-Porter's 1912 book "Moths of the Limberlost." It's a classic of natural history writing, written by a native Midwesterner. Chapter 6, "Moths of the Moon," is about luna moths. Stratton-Porter was a pioneering natural history writer, photographer, novelist, and film producer. She was also seriously into collecting and pinning moths, but when it came to lunas, she noted that dead specimens quickly lose their color, and that "a living moth must be seen to form a realizing sense of its shape and delicacy of colour." In the early 1900s, with only black and white photography at her disposal, she turned to watercolors to capture the luna's subtly clear greens, yellows, and purples.
Luna moth caterpillars are herbivores that graze on the vegetation of trees. All stages provide food for predators.
The tails on the hindwings of luna moths apparently disrupt the sonar that hunting bats use to locate the moths.
The caterpillars of luna moths can make clicking noises and vomit to deter predators.
Populations of our native saturniid moths (the family that includes luna moths) are shrinking as an unanticipated result of fly and wasp parasites intentionally introduced to North America to prey on nonnative, invasive gypsy moths. People concerned with the devastation caused by gypsy moth caterpillars identified insect parasitoids from the gypsy moth’s native lands and introduced them to America. Unfortunately, those parasitoids also attack several of our native saturniids, including cecropia, luna, and promethea moths, reducing their populations in New England and elsewhere. Meanwhile, those parasitoids have not ended the threat of the gypsy moth. The harmful effects on nontarget species are critical issues in combating invasive plants and animals.