The Lovely Luna Moth
The pale green wings and feathery tails of the luna moth make it an especially lovely sight.
While plenty of people are interested in attracting butterflies to their gardens, most of them overlook moths. People often think moths are dull in color, or too small to be of interest, or will chew on their stored sweaters (a bad rap that belongs to only a few select species). As a matter of fact, there are plenty of big magnificent moths out there, and one of the loveliest has to be the Luna Moth (Actias luna), a pale green gem found throughout the eastern U.S. and Canada.
This large night-flying moth has a wingspan of up to 4.5 inches (a little smaller in the Deep South), with tails that extend an inch or two from the bottom wing. These tails are part of the luna moth defense system: predators like bats will aim for the flashy tails, which the moth can easily lose without much hardship. The red-brown eyespots on their wings are also for defense; in the dark, these eyespots make the luna moth look like a much larger creature. Male and female luna moths look very similar, but you can distinguish between the two by looking at their antennae (which is true for most moths). Males have large feathery antennae for detecting the pheremones the females give off during mating, while female antennae are much more slender (a female is shown above).
Luna moths are members of the silkmoth family (Saturniidae), which boasts a peculiar trait: the adult moths have no functional mouth parts and do not eat for their entire existence. All the energy they need comes from stored fat from their caterpillar days, which gives them big bodies covered fur. The brilliant green caterpillars, which eat trees in the hickory family in the south and white birches (Betula papyrifera) in the north, can grow up to 6 inches in length and be as thick around as your thumb. (See a full host plant list and photos of caterpillars here.) They eat for many weeks before spinning a papery cocoon. In the south, luna moths have three generations each year. In the middle of their range, there are two generations, while in the far north (Michigan and north) they have only one generation per year. They spend the winter in cocoon, emerging in late spring or early summer each year.
To up their chances of finding mates, it’s not uncommon for most luna moths in one area to emerge within a week or two of each other, especially up north. In some places, that means that thousands of luna moths emerge from cocoon almost simultaneously on a June morning, climbing into trees where they spread their wings to dry and wait for evening. After midnight, the mating begins. Females often remain stationary, allowing the powerful flying males to find them. Within a few hours, the females are ready to lay eggs on their host plants. The process repeats itself for several more nights, until the moths have used up their fat stores. Within about 5 days, the average luna moth adult has mated, laid eggs, and died.
Luna moths rarely stray far from their host plants, as they don’t want to waste energy flying far distances. So many people may never encounter one of these beautiful creatures unless they happen to live near a birch grove, or have a large hickory, walnut, or sweetgum tree in their yard. They’re not particularly rare in most parts of their range, though, and you can try an old trick of the trade if you’d like to see one: night-flying moths are attracted to light, so hang a white sheet in your backyard and shine a bright spotlight on it. This often brings all kinds of nighttime bugs to visit. (Remember that artificial light can be a distraction to these moths, who should be focusing their attention on successful mating, so don’t do this activity for long periods of time.) Learn more about activities you can try to attract moths by clicking here.