Luna moth

Luna moths are arguably the most beautiful moths of North America. They belong to the family Saturniidae, which includes the Giant Silkworm Moths. The luna moth is one of the most recognized moths, and is used commercially by the company Lunesta in television commercials. It was even featured on a first-class postage stamp in 1987! 

"And to all the beasts of the earth and all the birds of the air and all the creatures that move on the ground—everything that has the breath of life in it—I give every green plant for food." And it was so."

--Genesis 1:30 (NIV)

Anatomy
Luna moths are known for their beautiful, pale green wings and their "tails." Every luna moth also has four eyespots, used to scare off predators. On their head they have feathery "plumose" antennae. These are especially prominent in males in order to sense female pheromones. The luna moth's wingspan tends to be between 4-5 inches. The front wings have maroon margins and the hind wings have a tail that can be up to 3 inches in length. Depending on where and when they were born however, some luna moths will have yellow forewing margins instead of maroon. The luna moth's body is white, contrasting sharply with its six maroon-colored legs. Mature luna moths don't have hearing organs and only have vestigial mouthparts that prevent them from eating. 

As caterpillars, luna moths go through five different stages of molting, known as "instars." They grow to be about 3.5 inches long. Although it varies during the different larval stages, the caterpillar remains green and has a yellow line down each side of its body with hair and spiny tubercles. These tubercles can be white, yellow, or even reddish orange.  The caterpillar also has various mouthparts that are used to chew mass quantities of food. Behind the caterpillar's head are three pairs of "true" legs. Prolegs, or "false legs," are attached in pairs to the remaining body segments. The head of the caterpillar can be either green or brown.  As a pupa, the luna moth looks like a dark brown egg spiraled to a tip at one end. 

Reproduction
Adult luna moths live only to reproduce. Because their lifespan is a mere week, luna moths mate and lay their eggs shortly after emerging from their cocoons. The females release pheromones to attract mates. Pheromones are specific chemical messengers that affect the behavior or development of other individuals of the same species; enables males and females to communicate during courtship and mating. (Miller & Levine pg 731.) Males trace these pheromones to find unmated females. The female will usually mate with the first male that reaches her. Once a male luna moth has found a female, they mate, remaining in that position until the next evening if left undisturbed. Luna moths perform internal fertilization, and begin mating a few hours after midnight.

Once the pair separates, the female looks for a host plant on which to lay her eggs. This plant will be one that the caterpillars can eat once they hatch. Oviposition lasts for several nights. Luna moth females will lay between 150-250 eggs on the undersides of leaves. The eggs hatch roughly 8-13 days later. The eggs can be laid singly or in small clusters. Depending upon the area, there can be anywhere from 1-3 generations of luna moths every year. 

Ecology
Luna moths do all of their eating as caterpillars, feeding on a variety of plants. These include pignut hickory, winged sumac, sweetgum, persimmon, white birch, walnut trees and many more. Because their diet mainly consists of leaves, luna moth caterpillars are known as folivores, which is a special classification of herbivores. Luna moths inhabit deciduous hardwood forests where they can find food sources. They are commonly found throughout the east coast of the United States, from eastern North Dakota and eastern Texas to the Atlantic. Luna moths live as far south as the Gulf Coast and central Florida, and as far north as Maine. In Canada, they live from Nova Scotia west to Saskatchewan. 

Luna moths are subject to predators at every stage in their lives. As caterpillars, luna moths are prey to parasitic insects from the Tachinidae, Ichneumonidae, and Pteromalidae families. Luna moths are also hunted by the bald-faced hornet, fiery searcher, big brown bat, great horned owl, and barred owl. For defense, luna moth caterpillars take advantage of their green, camouflaged coloring. If threatened, they can take on a "sphinx" pose, raising the front part of their body in an effort to look less like a caterpillar. Luna moth caterpillars can also regurgitate distasteful fluids if attacked by a predator, making a clicking sound with their mandibles as a warning. As adults, luna moths use their wings for defense. With their wings, luna moths can mimic dead or living leaves. They will also flutter their wings wildly if attacked.  Luna moths are nocturnal, and therefore rarely seen during the daytime. They are extremely attracted to light, especially UV wavelengths.  This is why, if seen at night, luna moths are usually fluttering around some kind of light.

Complete Metamorphosis
The luna moth's life cycle centers around a process called complete metamorphosis. Complete metamorphosis is: a "type of insect development in which the larvae look and act nothing like their parents and also feed in completely different ways."(Miller & Levine, pg 729) Luna moths begin life as a caterpillar hatching from an egg, going through 5 different moltings, or instars, before becoming a pupa. When a caterpillar is ready to become a pupa, it spins a cocoon from silk near its mouth, using a leaf to form the structure of the cocoon.  The cocoon usually has a line of small holes on one side, and is see-through if held up to a strong light. The male and female pupas can be told apart by two longitudinal notches on the ventral side of female pupas; males lack these. While in the cocoon, the pupa loses its prolegs, but retains its true legs. At the rear of the cocoon, the pupa is anchored to a pad of silk by hooked spines that allow the moth to leave the pupal exoskeleton behind. 

The metamorphosis takes about 2-3 weeks. If the caterpiller spun its cocoon shortly before winter however, it will wait until spring to emerge. The luna moths escape through a hole that is approximately 3/8 inch in diameter! Male luna moths leave their cocoons a few days prior to the females. Eclosion occurs in the morning, allowing time for the moth to pull itself free and dry out its wings. Also on this morning, the moth rids itself of the last of the old larval tissues. By emerging in the morning, the luna moths have time to dry out and rest up for their nocturnal flight and search for a mate.