Summary : Luna moths are nocturnal insects that you may find flitting around a light outside. These creatures may be confused with other more common moths, but this species of moth is actually not harmful.
Luna moths, also called moon moths, are night flyers from the giant silkworm moth family. They like to live in forested areas. These moths are one of the largest species and typically are about 4 inches in wingspan, although it could be as wide as 5 inches. They are strongly attracted to light, and will most often be found flitting around your exterior lighting.
Adult Luna moths are much admired because of their beauty. They have pale green wings with long tails and a yellow and blue eyespot on each wing. The antennae are feathery, but the males' antennae are bushier than the females. Luna moths only live for a week as an adult. The Luna moth loses its digestive system in the cocoon. Without a mouth to feed, the moth's only task is to mate. The females usually die shortly after laying their eggs. They spread their eggs out on the bottom of different leaves of host trees with 4-6 eggs on each leaf. Eggs will hatch in 10-12 days.
Luna moths feed constantly during the larvae stage, which lasts for 3 or 4 weeks. In the north, the eating stage can be stretched even longer to about 6 weeks. Luna larvae begin with a yellowish green color with a darker head and a yellow stripe along the sides of their bodies, but as they mature, they become more of an amber color. Their favorite eating places are the leaves of butternut, hickory, and walnut trees, although they will feed off of many other trees such as maple, sweet gum, oak, persimmon and willow. Their continual eating causes them to outgrow their current skin. It becomes necessary for the moths to molt four times before spinning themselves into a cocoon. They become increasingly fatter and longer until they reach about 3 inches in length.
When they are ready to pupate, or go into a cocoon, they wrap themselves in leaves. They may do this on the ground or they might start on a branch and the cocoon will fall to the ground after being spun. After emerging from their cocoons the Luna moths will hang from a twig or leaf and inflate the veins of their wings with blood before they can fly. This can take up to 45 minutes, but the moth will continue to hang afterwards in order for the wings to become firm.
Although they might be annoying flying around your exterior lighting, Luna moths are not actually considered to be pests. Since the females space their eggs out, the Luna moth population should not become overwhelming for any particular wooded area. Since the moths are so evenly dispersed they do not cause any harm to their host trees and therefore, should not really be considered a pest.
In all actuality, Luna moths are currently on the endangered species list. Street lights and pesticides have caused the significant decrease in Luna moths. Another cause of their decline could be attributed to efforts to remove the pesky gypsy moths. Luna moths also have several predators that have added to their decrease, including owls. One of the most common tactics of defense is to mimic the look of leaves in order to hide from predators, although they also flutter their wings in order to scare off predators with the eyespots found of each wing. They can also be distasteful to many predators which also protects them from harm. Unfortunately for the hungry little caterpillars, chubby little Luna larvae can be a favorite treat of birds, decreasing the population before the larvae even mature.
So before you try to get rid of these moths, stop and admire their beauty. They're not harming you or the trees from which they feed. What a relief! One less bug problem for which you have to find a solution.