Take it from someone who has seen one: The green-colored luna moth is a truly beautiful insect.
The luna moth has a wingspan of 4 inches, and each wing has a prominent eyespot. The tops of the front wings are edged with purple, and the hind wings end in long tails.
The moth usually hangs beneath leaves with its wings folded together during the day. Those long projections of the hind wings are also folded together, so the moth resembles a leaf complete with stem, camouflaging it from predators while it rests. Found only in North America, the luna moth is seen from late May to late June in Minnesota. Look for the moths on porch lights left on overnight. Streetlight posts are another possibility.
According to my field notes, I saw lunas in early June 2012 in both southern and northern Minnesota. On June 2, I spotted two mating pairs just a few yards apart in Lutsen.
Females may lay as many as 200 white eggs, fastened to twigs and upper leaf surfaces of oak, birch, aspen and willow. All summer, the green caterpillars grow as they eat the leaves, and in the fall they spin cocoons among the leaf litter where they’ll spend winter. Luna moths live on the leaf energy that the caterpillars stored the previous summer. The adult moths don’t eat; they don’t have mouths. Their only purpose is to mate, and they only live about a week.
Jim Gilbert’s Nature Notes are heard on WCCO Radio at 7:15 a.m. Sundays. His observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.