The Nature Nerd

Focus on: Miracle moths of May


A cecropia moth, the largest moth in North America and a Northwoods resident. Submitted photo.

Acecropia moth, the largest moth in North America and a Northwoods resident. Submitted photo.

Moths are underrated. Moths usually are regarded as drab insects of the night. One rarely hears superlatives used to describe moths. A few of us know better. Several of our earlyseason moths are spectacular insects.

Several kinds of moths get big, having wingspans of over four inches. Sometimes, as they fly, they are mistaken for bats! Some people find then scary. As a group, these big moths are known as giant silkworm moths. We have several kinds.

The most common of these are the cecropia moths. They are an amazing sight! First, they are big, with a wingspan of as much as six inches. They are the largest moth in North America! And, they are beautiful, with multi-shades of brown with white trimming. The patterns are amazing, especially on the abdomen, which has stripes of bright brown and white.

Other giant silkworm moths occurring here include the Polyphemus, which have amazing eyespot patterns on their wings. The luna moth is another; it is bright green with eyespots and long tails on their wings. If you ever see any of these moths you will never again simply dismiss moths as drab insects!

The giant silkworm moths have interesting life histories. As adult moths they do not feed! Ever! They do not even have mouth parts to make feeding possible. Their lifespan as adults is very short, a couple of weeks, at best. Their one and only concern during adulthood is mating and laying eggs.

Feeding is done as the caterpillar. They feed on leaves of numerous kinds of trees and shrubs. Feeding is important! They must eat enough to grow into large caterpillars, make a cocoon, winter and transition into moths, and—in the case of the female—to produce eggs.

These moths are closely related to true silkworm moths, which produce the fabric.

They produce silk fibers that are used for their cocoons. The cocoons have two distinct layers. The outer layer is a fine-textured and thin. The inner layer is looser and thicker. Together these layers produce a cocoon that is very tough and durable. Anyone who has ever tried to open one can tell you that. A tool must be used, small sharp scissors are best. So, how does the moth escape from the cocoon? An escape hatch is made by the caterpillar at one end, through which the moth can barely squeeze out. The moth’s life in the cocoon is miraculous! When you see the moth

it seems incredible that it came out of the cocoon; is seems incredible that it could ever have fit inside, much less escape. And, how does it get those amazing wings out of the cocoon? These changes are part of what makes the mega-moths of the Northwoods miraculous!

Jerry McCormick lives in Virginia, MN. He is a retired natural resources professional and is a self-described nature nerd.

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