The luna moth: Mother Nature’s masterpiece

Mother Nature must have been in one of her most artistic moods when she designed the luna moth, for she created a masterpiece. Catching sight of a luna as it sails through its nocturnal kingdom on delicate green and purple wings, dancing in and out of the moonbeams, will leave anyone in its wake spellbound and gasping.

Emergence

The luna moth (Actias luna) is a member of the family Saturniidae, a group known as the giant silk moths, the largest, most colorful lepidoptera on the planet. It is also the first of these showy moths to emerge in the spring, and here in northeast Ohio, that occurs right around Mother’s Day.

After spending the winter in a flimsy, brown, silken cocoon hidden among the leaf litter, the adult moth commences its emergence by secreting powerful enzymes from glands on its head. These aid in dissolving the tough silken threads of its enclosure, creating an exit hole which the insect enlarges using tiny knife-like structures that act as a pair of scissors. If one listens closely, they can hear the tiny sounds emitted as the moth labors. Finally, after several minutes of hard work, the insect emerges, crawling and climbing until it finds a sturdy sheltered location in which to conduct its amazing transformation.

Indiscernible at first, the moth sports a tiny set of crumpled wings and an overly round abdomen. Slowly, peristaltic waves can be seen moving across the body as it begins to pump fluid into its wings. As if by magic, and right before one’s eyes, they can be seen lengthening and unfolding while at the same time, the abdomen shrinks in girth. Although the wings reach their full potential in only about 15 minutes, the process of drying may take 4 to 5 hours. luna moths emerge from their cocoons in late morning, so that by nightfall, their wings are ready to carry them into the depths of the forest.

Appearance

It is hard to describe the luna in all of its glory. At its core is a body white as snow. Long, specialized scales, appearing more like fur, emanate from the head and thorax spreading out a short way across the upper set of wings. This soft, dreamy appearance is punctuated by a pair of jet-black eyes, above which stretch a set of yellow antennae. Appearing as tiny ferns, or feathers, the antennae of the male are much fuller (a nice contrast between the sexes) and act as satellites, used to hone in on tiny particles of pheromones emitted by the females up to several miles away.

On either side of the moth’s abdomen are squiggles of lavender, a delicate feature unobservable unless the moth is in hand. Its six legs, each terminating in a set of tiny hooks which aid in gripping and climbing, are a shock of reddish purple. Yet the pièce de resistance are its glorious wings, a set of four to be exact, which are a stunning pale shade of green and nearly translucent. The leading edge of the two upper wings sports a lovely border of lavender that traverses uninterrupted across the nape of the moth’s neck. On each of the upper set of wings, a stalk-like marking curves down from this border, terminating in a translucent window bordered by scales of black, yellow, purple, blue and white. A similar, somewhat larger pair of markings adorn the lower set of wings as well. These colors combine to produce the likeness of “eyes”. When a predator attempts to grab the moth, the wings quickly open to expose these eyespots, startling the predator just long enough for the moth to escape.

Unique tails

Yet the most enchanting feature of the luna’s physique can be found on the lower wings where a set of long, twisted tails trail off from the bottom edges. Edged in purple and yellow, the tails flutter in the breeze as the moth travels along, giving it a most mystical quality. Yet Mother Nature is not frivolous. These trailers are perhaps the most important attribute the moth possesses. You see, a luna moth is a tasty morsel for any bird. If pursued, the moth with make sharp, acrobatic movements, causing its twisted tails to ripple out behind it. Predators can’t resist but to zero in on these structures and often end up with a mouthful of wing, the tails sacrificed as the moth escapes. I have observed many a lucky luna moth at my porch lights that have benefitted from sacrificing this unique anatomical structure.

In addition, scientists have discovered that these tails also aid the moth in its escape from bats. As bats fly, they send out sonar in search of prey. This echolocation helps locate objects as fine as a human hair. As the bat hones in on a luna moth, its twisting tails interrupt the waves of sonar, confusing the bat and buying the moth its freedom. Interestingly, the luna is the only North American member of the giant silk moth family sporting these tails.

Reproduction

At nearly 5 inches across, the luna moth is a sight to behold. In this final stage of its metamorphosis, it has no mouth parts and cannot not feed. With only around 10 days of life remaining as an adult, the moths have but one thing on their mind. During their first night after emergence, females release pheromones, tiny particles of scent, which attract the males. After mating throughout the following day, females set out into the woods at nightfall, depositing their eggs on specific host plants including hickories, walnuts and sweetgum. These will hatch into caterpillars which will spend the summer months munching away before finally spinning cocoons in which to overwinter.

It is hard to believe that while we sleep, an enchanting insect is fluttering in the moonlight, going about its business of depositing it eggs in an effort to ensure that future generations will persist. The luna moth is truly a jewel, a treasure … a masterpiece.

Video

I have been rearing giant silk moths for most of my life. If you would like a rare, up-close look at a luna moth emerging from its cocoon, please turn up your volume and visit youtube.com/watch?v=vJVV3QPFGeY.