Thursday, June 27, 2013

Summer Sights: The Luna Moth

One of the fun parts of my job is getting emails like a recent one from a colleague, Rob Van Cleef, saying something like, “Hey Dorothy, I’m over at Dan Tymann’s house and we saw a big insect. Do you know what it is?“—followed immediately by an email from Dan with a picture attached. The next day, in conversation with someone else, the same insect came up. "Look," my friend said, showing my a picture on her cell phone, “I found this at my house. What is it? ” 

Delightfully, it was one of my favorite summer sights, and a rare treat: a luna moth. So in case you are out and see a giant moth with light green broad wings, and wonder—here’s a tidbit of entomological lore:

The beautiful luna moth, Actias luna, is native eastern North American species in the Saturniidae, the family with the largest moths, including silk moths. They have light green wings with long tails on the hind wings and eye spots on the forewings. The eye spots fool predators away; when flashed suddenly, they look like some type of bird. Luna moths are nocturnal and live in deciduous forests. Around here, some of the trees they would eat as caterpillars include walnut, sumac, and white birch. One of the reasons you will rarely see them is because they live only a week as an adult, and do not even eat in their adult form. 

All of the large silk moths are in decline, although the luna is the most common of them.  Silk moths have declined in part because of an invasive parasite, although habitat loss and other factors play a role. Light pollution has a particular effect. Like many nocturnal creatures, silk moths orient themselves by light, and lose their way when artificial lights overwhelm the signals from natural lights like the moon. If you are moon gazing and a Luna flits buy, shut off your lamp, stand in the moonlight, and take a minute to enjoy this lustrous delicate creature. 

If you want to go even a step further, submit photos of butterflies and moths to the web site of Butterflies and Moths of North America. They use hundreds of citizen scientists who send in sightings to track moths and butterflies and better understand their conservation.

Curious about a particular North Shore plant or creature? Let us know in the comments!

Dorothy Borse, Ph.D., is professor of biology at Gordon College. This summer she will be sharing a series of informative reflections on the College's campus and its natural surroundings. 

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