Moths are often considered the homely stepsisters of butterflies. Drab and unexciting, to the untrained eye they pretty much all look alike. But one, the Luna moth, rivals any butterfly in beauty. Google “most beautiful moth in North America” and the Luna moth will be at or near the top of the list.
Female Luna moths are larger than males.
The Luna moth (Actias luna) is also called the American moon moth. It’s named after Luna, the Roman moon goddess, and also because the spots on its wings resemble moons (they’re actually called eyespots).
A type of silk moth, they are not endangered, but people don’t often see them. No other moth looks like it, so if a huge, pale green “butterfly” appears on your window screen one summer night, you can be sure it’s a Luna moth, and thank your lucky stars that you saw one.
That’s because despite being one of North America’s largest moths, they’re not easy to spot. They live as adults for only seven to 10 days, fly at night, and blend into tree foliage during the day. I’ve seen one only once, years ago.
Appearance: The 4 ½ inch-wide wings are pale or light green, with a grayish band running along the top, and four spots, one on each wing. Their tails are long and swoopy. They have white bodies and distinct, feathery antennae.
Male Luna moths have more prominent antennae than females.
Distribution and habitat: Luna moths are found in deciduous forests in more than half of upper North America, in every U.S. state and Canadian province from Nova Scotia and Maine down through Florida and the southeast, and west through Saskatchewan down to Texas.
Life cycle: One to three generations per year; a single one in colder climates such as Maine, up to three in southern climates. Females lay 200-400 eggs.
The caterpillars are bright green, with pale hairs on their backs. Their coloring conceals them in vegetation. They pupate wrapped in leaves.
Adults don’t eat during their brief lives. With no working mouth or digestive system, they survive on the energy they stored as caterpillars. They emerge, mate, and die.
Host plants: Many different types of trees, including white birch (a favorite of northern moths), hickories, walnuts, sweetgum, persimmon (four favorites of southern moths), willows, smooth sumac, wild cherry, pecan, beech, white oak, and red maple.
Threats: Luna moth caterpillars and adults are, like most insects, part of other creatures’ diets, including insects such as parasitizing wasps. However, they have an advantage over at least one predator. Researchers believe a moth’s long tails interfere with a bat’s echolocation, making it harder to catch.
And as with threats to so many insect species, we play a part as well. Habitat destruction, elimination of host trees, pesticides, and pollution – particularly light pollution – create an environment inhospitable to the Luna moth’s survival.
How to encourage them: Plant their host trees: birches, sweetgum, hickories, walnuts, persimmon, willows, pecan, wild cherry, beech, white oak, smooth sumac, and red maple.
How to see one: Luna moths are irresistibly attracted to light. The moth I saw had flown into a garage, of all places. Seeing one is more by chance than planning, so on balmy June and July nights, look up into your nearest streetlight, cross your fingers, and hope.
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