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The Luna Moth

green luna moth
A male luna moth, Actias luna (Lepidoptera: Saturniidae)

Entomologist Dr. Art Evans and WCVE producer Steve Clark discuss the ever popular luna moth.

SC: I'm Steve Clark with Dr. Art Evans, entomologist, and this is What’s Bugging You.

AE: Guess what I saw the other night?

SC: What?

AE: Spiraling around the streetlight out front was my first luna moth of the season.

SC: I love those.

AE: It was so obvious what it was, because it had those long tails. I could see it from a distance. I didn't even have to go out there and figure out what it was. I knew exactly what it was.

SC: And they stay in good shape for how long?

AE: Not long, life is hard on those tails. (laughing)

SC: I remember my first luna moth. I saw it at a miniature golf course way out in the country with all those lights, and there were many luna moths.

AE: We've had several luna moths in our neighborhood over the years, and I think the caterpillars are feeding on sweet gum, but they feed on other things too. You'll find them on walnuts and sumacs. Hickories are another favorite food plant as well for the caterpillars. The best luna moth story that I have to share is I was doing a beetle survey in the Bull Run Mountains in Northern Virginia, and I put up a light to attract insects, mainly looking for beetles of course, and I got a baker's dozen . . .

SC: Oh my gosh.

AE: . . . luna moths, and they were all freshly emerged. They were just brilliant green, and they had sort of purple-ish edges on their wings. It's something that's interesting about them. They show phenotypic variation. The moths that are emerging in spring over-winter as cocoons, and the spring moths come out, they mate, you get a new crop of caterpillars. They pupate in cocoons that are silk, and usually incorporate a leaf in there, down in the soil at the base of the food plant. They’ll emerge in summer. And instead of having those purple-ish wing margins, they're sort of yellow and they're not as bright green as the spring generation. They're more yellow in color. So you can take a collection of luna moths, and you can actually tell to which brood they belong, whether it's the spring brood or the summer brood. Well, we've talked about relatives of luna moths because people will send in pictures of the cocoon of the polyphemus moth.

SC: We’ve had one in front of the building that we watched the whole winter.

AE: That’s right. They make a very distinct cocoon, and it's hanging down by a silken strap, and usually by the time people find them there's a nice emergence hole. But in luna moths, they don't create a nice emergence hole from the cocoon. They're able to sort of tear their way out of this very loosely woven cocoon and then work their way up to the surface and then crawl up a tree and let their wings fully develop, and then they're on their way. The males are very distinctive because they have very large feathery antennae. Whereas the females, they're not so well developed and usually by the time you will see a female, they've already mated. And if you feel like rearing the caterpillars, you can capture a female and gently put her into a small paper bag, and she will lay eggs. Caterpillars will hatch in about a week, and if you provide them with branches of sweet gum leaves, you can watch them develop over about a month, month and a half.

SC: And then they'll pupate?

AE: And then they'll pupate. They'll start wandering around, and you need to supply them with some soil where they can bury themselves in some leaf litter. You don't want it wet, but you don't want it super dry either. And then of course when they emerge, you release them later that summer.

SC: So you could have a green thumb?

AE: (laughing) You could, of a different sort.

SC: Dr. Art Evans is a Research Associate at the Virginia Museum of Natural History. You’ll find photos, audio, and links to the museum and Art’s Facebook page at ideastations.org/radio/bugs.

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Dr. Arthur V. Evans teams up with WCVE Public Radio producer Steve Clark for a weekly feature, “What’s Bugging You?,” which airs during NPR’s Morning Edition. The program takes its name from another of Evans’ books “What’s Bugging You – A Fond Look at the Animals We Love to Hate.”

Tune-in each Tuesday at 8:45 a.m. or at 5:44 p.m. on 88.9 WCVE, Richmond’s Public Radio station.