I had a banner year in 2018, as I saw three luna moths at my house. As a seasoned horticulturist and wannabe naturalist, I’ve probably seen fewer than a dozen in my life. I would ask: How many have you seen? Or have you ever seen one?
Some recent photos on Georgia Nature Photographers Facebook page made me realize the moths are spectacular in every form of their brief life. Like a lot of butterflies, they go through a molting process. Each molt is followed by a four- to 10-day interim period, or “instar,” and five of those occur before cocooning.
Like butterflies, they are vulnerable at this stage but have a couple of defense mechanisms to stave off reaching “happy meal” status. They can rise up, looking somewhat menacing I suppose, and they can make a clicking sound with their mandibles. If the threat calls for the ultimate, they will vomit a vile-tasting mess that makes them far less appealing. And their green color is quite the camouflage.
Most don’t realize it, but the luna moth is one of the giant silkworm species. To prepare for the pupae or cocoon stage, the caterpillar spins a silk yarn wrapped in a leaf where it will undergo the final transformation to adulthood in two to three weeks.
The escape from the pupa, called eclosion, is quite the effort, as they use spurs on the base of their front wings to cut their way out. For males, this normally takes place in the morning and days earlier than for females. As with butterflies, they have a drying period before they can fly.
Before I knew better, I fantasized about luna moths visiting my night blooming moonflower. This would make for good literature, but the luna moth adult has no mouth or digestive system. It has only one job: Mate. And the clock is ticking.
Female luna moths release a pheromone that attracts males from quite a distance. While she stays in place, the male trying to reach her takes a treacherous journey, risking predators such as owls and bats. A Smithsonian Institution study found another amazing defense mechanism. The moth’s twisting tails create sound patterns that interfere with the sonar-like echolocation used by bats. The clock is ticking.
Once the lovefest has occurred, she stops releasing pheromone and will not mate again. She will begin her first flight, and her clock is racing too. She’ll lay four to seven eggs at a time — 400 to 600 total — on larval food sources such as birch, oak, hickory, sweetgum, willows and walnut trees. The male looks for more females, but his stored energy is waning. After all, he can’t eat. His clock is racing too.
Linnaeus named the moth Actias luna, referencing Luna the Roman Goddess of the Moon. You have to love the family name too, Saturniidae. With a seven- to 10-day lifespan, ruling the night, they’re on many nature viewing bucket lists. One thing I can guarantee. When you do see one, you will ooh and ahh and remember it as one of the special moments in your life.
Norman Winter is a horticulturist, garden speaker and author of “Tough-as-Nails Flowers for the South” and “Captivating Combinations: Color and Style in the Garden.” Follow him on Facebook @NormanWinterTheGardenGuy.