Northland Nature: It’s luna moth time

With all the rain, fog and clouds that we saw during the second half of May, we might have forgotten those days that were clear. But sunshine did happen often during this greening month and warm days were common enough to cause the month to once again be several degrees above the normal.

We were not the only ones to take advantage of the sunlit days. This summer could be quite a good time for butterflies.

On a recent bike ride on the Willard Munger Trail and hiking nearby, I noted about ten kinds. These ranged in colors from blue to brown to yellow to orange to white and even black.

They also showed diversity in size from the diminutive blue spring azure, about as big as a thumb nail, to the palm-sized orange monarchs and the yellow tiger swallowtail.

In addition to these three, the flying flowers included two species each of sulphurs, whites, painted ladies, dark mourning cloaks, dusky-wings, and a red admiral.

The monarchs proved to be the most numerous, a very good sign for the Northland, but others were common here too. There seemed to be a constant movement of these large colorful insects.

Though I thought they put on quite a show, they look upon these days as ones of opportunity. Warmed by basking in Sol’s light, they spend the bright hours taking nutritious nectar from flowers, mating and laying eggs.

I found monarch eggs on a small milkweed already on May 25. Last year these migrants still had not returned to the region by that date. At night and on days of less attractive weather, the butterflies go into the protection of leaves as they roost or wait until the sunlight returns.

But in the evening, their cousins, the moths, will take flight. Butterflies and moths belong to the same order of insects, the Lepidoptera.

Though we see and appreciate butterflies more, moths far outnumber them. Some moths are better known as caterpillars than as adults; tent caterpillars (armyworms), woolly bears, hornworms are examples.

Occasionally, we find a marvelous adult moth that makes us stop and take a close look.

As I walked the trails twice in the last few weeks, this happened to me. Both times, I was stopped short when I came up to a dazzling green luna moth. With wings that are up to four inches across and nearly five inches long, they are bigger than any of our many butterflies.

The light green wings also hold large white “eye spots.” (These are not true eyes, but appear as such on the wings and so confuse a possible predator.) The hind wings stretch out to a thin and lengthy “tail.” It is the arc of these wings that gives the moth its name.

The luna moth is named after the earth’s satellite Luna, usually called Moon. We all see the various shapes of this orbiting object as it circles the earth. Some naturalist thought that the hind wing arcs were shaped like that of the crescent moon, and so the moth was called Luna.

The thick body is hairy and white with huge feathery antennae. The fat body contains food stored from its caterpillar stage; and now as an adult, it lives on this supply, not eating at all in maturity. Their flights of late May and early June are spent locating each other, mating and laying eggs.

The antennae are extremely efficient as pheromone finders, and males pursue the females in the dark from great distances. After mating and laying eggs, their lives do not last long. Caterpillars hatch later in summer and feed on a variety of tree leaves, including maple and birch.

If we see these beautiful adults at all, it might be at night when they get confused in their nocturnal flights and come to our porch lights. Or maybe we could be as lucky as I was, and find one that is spending the daylight resting on a plant, relying on its green wings to blend in with the forest foliage.

They won’t last much longer, but finding a luna moth is always as much of a delight as seeing the large number of butterflies that are now with us.

Retired teacher Larry Weber is the author of several books, including “Butterflies of the North Woods,” “Spiders of the North Woods” and “Webwood.” Contact him c/o budgeteer@duluthbudgeteer.com.

Tags: budgeteer, outdoors, environment