Cecropia Moth – Largest Native Moth in North America

  • Post published:07/11/2020
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female Cecropia moth
Female Cecropia moth

The Greenfield Garden Club Garden Tour has been postponed to Sunday, July 12, 2020 due to the weather. Tickets and maps for the tour, $10, are available Sunday morning from 8:30am  to 1 pm at the John Zon Community Center on Pleasant Street. Ten beautiful gardens will be on display. Hope to see you  there  with  your masks. Social distancing required.

The importance of pollinators in our own gardens, and in public gardens like those at the Energy Park and the John Zon Community Center cannot be over estimated. Pollinators are vital to a healthy environment. However, I am now learning about a beautiful moth, Hyalophora cecropia, that is not a pollinator.

The Cecropia moth is the largest native moth in North America. It is a member of the giant silk moth Saturniidae family. They get their name from the silkiness of their cocoons. Like many creatures they are endangered; it is important that we all become aware of the importance of protecting native creatures, and plants.

Cecropia eggs
This year’s Cecropia eggs

I was introduced to these beautiful moths by my friend Susan. She has an expert, Cecropia-loving friend who mailed her approximately 25 Cecropia eggs in late May of 2019. Most of those eggs hatched and the tiny caterpillars began the cycle of eating apple leaves from a tree in Susan’s yard and growing through five stages of development called instars.  I was fascinated when Susan told me Cecropia caterpillars are called ‘gregarious’. “Sometimes three to five caterpillars may feed closely on the underside of a leaf.  They seem to seek each other, to be close to each other,” she said.

Cecropia caterpillars
Cecropia caterpillars are sometimes ‘gregarious’

She invited me to visit with my husband this June. We started at the wood, screen and hardware cloth box that her son made. The box was built to keep the caterpillars safe from predators. We saw several branches with cocoons that were attached to the inside of the box. I was confused because I thought the cocoons were dried leaves because of their irregular shape and  color. They had been there all winter. The Cecropia moths were hatching, a few every day – first the males, mostly, and then the females. Male moths emerge in the morning and early afternoon and by dusk are ready to take flight. One cocoon had just hatched and we saw the new Cecropia moth pumping up its wings.

Cecropia caterpillars
Two Cecropia caterpillars at two stages, instars, of development

Susan explained that in the fall Cecropias go into the cocoon phase which is called diaphase. Inside the cocoon, which is constructed to hold on a thin branch or other support. A change occurs that morphs the caterpillar in a pupa. The cocoon, which has three layers, protects the future moth from the brutal temperature and weather (winds and ice) of winter!

One cocoon had just hatched and we saw the new Cecropia moth. I had never seen a Cecropia which has such beautiful and unusual coloring of white and gray and reddish brown.  I was surprised by how fuzzy it seemed.

One pair of Cecropia moths are mating while another female is waiting below. Look closely to see their body parts touching.

Then we went to her special hardware cloth mating cage and saw a female moth. Susan said the females are docile. “They will emerge from the cocoon, pump up their wings, and wait patiently for a male, sometimes for more than a day.” The female moth’s pheromones, emanating from a retractable protrusion at the end of her abdomen during the dark hours from dusk to dawn, attract a male who fertilizes her eggs. Males have large antennae that sense pheromones. Males usually arrive near dusk or before dawn. When they arrive they connect onto a female for up to 24 hours and then they will leave.”

This Cecropia moth died in its cocoon.

By mid-August, each caterpillar reaches a point where it finishes eating plant material and starts to construct a cocoon from which it will emerge as a moth the following  spring. The sole purpose of the adult stage is to mate and lay eggs. Adult moths cannot eat, so if a bird doesn’t scoop them up, they will die within two weeks.

Susan is very aware of her surroundings, the plants she tends and the creatures that visit her garden. She does not use chemicals of any kind. She mentioned that other caterpillars, such as black swallowtails, may be found on parsley and dill in the garden, but they do little damage and should not be killed. I understand her reminder. Swallowtail butterflies are so beautiful that I have always been willing to share my parsley and dill with their caterpillar form.

Since people are becoming more interested in pollinator plants and pollinator insects I think we will become more aware of the benefits and the beauty that that many insects bring to our gardens, and to our environment.


Cecropia moth, 3rd instar
Third instar – the caterpillar is shedding it’s skin and eating it.
Cecropia caterpillars
Cecropia caterpillars
Photo of the Cecropia moth with a clear view of its body

Between the Rows  July 4, 2020

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