How to Identify the Beautiful, Endangered Luna Moth

Luna Moth on Geraniums

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If you have seen a live luna moth, consider yourself lucky. This large, beautiful moth is part of the Saturniidae family. It is sometimes called the giant silkworm moth or the American moon moth. Once a very common sight, the luna moth is considered to be endangered in some areas, although it is not officially on any endangered species list.

Identifying the Luna Moth

The luna is one of the largest of moths in North America, with a wingspan of 4.5 inches. Because there are so few, and they are nocturnal insects, it is very rare for people to see this unique moth. Its name, "Luna," meaning moon, is attributed both to its nocturnal nature as well as the crescent in the eyespot of its wings that resembles a crescent moon. It can be identified by several characteristics:

  • Its body is white, its long legs are pinkish, and its large wings are translucent and lime green. The hind wings have eyespots and long tails to confuse predators.
  • The male's antennae are larger and bushier than the female's.
  • The luna moth is found in forested areas in the Northern hemisphere. In southern Canada, it can be found from Nova Scotia to Saskatchewan. In the United States, it can be seen in every eastern state from Maine to Florida and as far west as Texas.
  • Luna moth larvae feed on plant leaves, including hickory, walnut, sweet-gum, persimmon, birch, American beech, red maple, white oak, black cherry, willow, American chestnut, and smooth sumac trees.

Luna Moth Lifecycle

Seen primarily during spring and early summer, the moth typically produces two generations each year. Male luna moths are particularly strong fliers and may fly over relatively long distances. Female luna moths release a sex-attractant pheromone that is used to attract the male moth from a great distance. The mating usually occurs during the first couple of hours after midnight.

Once the moth mates and lays its eggs, it dies. In about 10 days, the eggs hatch into caterpillars, which immediately begin to feed, grow, and molt. The luna moth molts about five times for three to four weeks until it is about 2.5 inches long. At this time, it begins spinning a silken cocoon wrapped in a leaf. It cocoons for two to three weeks before emerging as an adult moth. Usually emerging in the morning, the moth hangs and rests through the day to allow its wings to inflate with blood before it flies off at night to seek a mate.

Once it becomes an adult, the luna moth no longer feeds at all (in fact, it has no mouth for feeding). It will live for only about a week as an adult, during which time it mates, and the female lays her eggs. Most female luna moths lay about 200 eggs in small batches on the undersides of leaves.

Predators of the Luna Moth

The luna moth's natural enemies include owls, bats, bald-faced hornets, Fiery Searcher ground beetles, and parasitic wasps. During its caterpillar stage, it deters predators by rearing its front end in a "sphinx-like" stance, making a clicking noise with its mandibles, and regurgitating a distasteful fluid. Additionally, the luna caterpillars get protection from predators by their green coloration, which often camouflages them within their natural surroundings.

Avoid Population Control

Due to its beauty, the luna moth is not considered a pest, and control efforts are not necessary or desirable. In fact, the use of pesticides, loss of habitat, and pollution are some of the reasons it is endangered. Although the luna moth larvae are large caterpillars that feed on the leaves of many shrubs and trees, their populations don't grow large enough to be a source of significant damage or destruction.