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Weekly “What is it?”: Luna moth

The brilliant colors of the pink-spotted hawk moth rival those of many butterflies. Photo credit: Smithsonian Magazine

We hear about butterflies all the time–their beautiful wing patterns, how to plant entire gardens for them, and the fascinating migration patterns of monarchs. But if you look around, you might just find their night-dwelling cousins, the moths, have some pretty incredible traits, too. I distinctly remember proudly featuring a giant pink, fuzzy, hawk moth in the middle of my junior high bug collection project. Unusual and colorful insects were sought after commodities for that assignment, and when I came across a dead one in my backyard, I knew I’d hit the jackpot.

The moon-like eyespots and long tails on its wings are identifying features of the luna moth. Photo credit: Carrie Stevenson, UF IFAS Extension

I find luna moths (Actias luna) just as interesting as the pink-spotted hawk moth I admired many years ago. Luna moths are considerably larger than the little brown and black moths you see fluttering around streetlights. Their wingspan can be up to 4” wide, with long, tapering tails trailing behind them. They are pale green, and adults have a furry white underbelly. Lunas are so eye-catching that they have been featured on the cover of a field guide to moths, postage stamps from multiple countries, and as the mascot of the insomnia medication, Lunesta.

Luna moths have several celestial ties in their name. All the moths in its larger family, Saturnidae, have round eyespots (which fool would-be predators) composed of concentric circles like the rings of Saturn. “Luna” comes from the Latin for moon, after the moon-colored eyespots on its back.

The caterpillar of the luna moth is bright green and warns off predators by making an intimidating clicking sound. Photo credit: University of Florida

The moth is native to the entire eastern portion of the United States, but has a longer life span the further south it resides. Luna moths live year-round in Florida, with up to three generations (trivoltine) born annually.

Luna moth caterpillars are fat and green—the classic caterpillar—and about 2.5” long. Their preferred host plants in the south are typically sweet gum, hickory, walnut, and persimmon trees. Interestingly, the caterpillars can make a sound, typically described as a clicking noise. Biologists believe this noise-making is a defense mechanism, performed as a precursor to spitting up unpleasant fluids to fend off predators. Several studies have shown that the twisting motion of the adult luna moth’s long tails in flight can interrupt the echolocation of bats, helping the moths evade predation.