A Caterpillar-Raising Extravaganza!

Posted on February 28, 2020 by barb

Cecropia Moth caterpillar in its last stage of development. July 2017. © Barb Elliot. Click to enlarge.

By Barb Elliot, Ph.D.

In July 2017, I came home from Mothapalooza, a conference for moth enthusiasts, with a Cecropia moth (Hyalophora cecropia) caterpillar. I was excited. The beautiful adult Cecropia (Hyalophora cecropia) is the largest moth in North America with a wingspan from 5″ – 7″. The showy caterpillars are chunky and grow to 4”- 4.5”. Although I had raised butterfly and moth caterpillars previously to increase their chances of survival, I now had the opportunity to observe the life cycle of this iconic silk moth and learn about its role in our ecosystem.

My caterpillar was almost full grown, but still had a voracious appetite. I kept it in a butterfly cage, provided a constant supply of fresh River Birch leaves, and removed the caterpillar waste (frass) each day. Cecropia caterpillars can eat other native tree and shrub leaves including elm, oak, maple, apple, cherry, ash, sassafras and willow, but prefer to stick to one kind once they begin eating. A Cecropia caterpillar gains more

Cecropia caterpillar making its silk cocoon enclosure. © Barb Elliot. Click to enlarge.

than a thousand times its weight between hatching from its egg to being fully grown and ready to pupate and spin its cocoon.

In late summer, my caterpillar clung to a twig in the cage and spun a cocoon around itself. Inside the protective silk, it changed from a caterpillar to a dark brown pupa, the third stage in its development.

A completed Cecropia cocoon. © Barb Elliot. Click to enlarge.

Many months later, on June 21, 2018, with metamorphosis complete, a spectacular female Cecropia moth emerged (eclosed) from the cocoon. With only a week to live and with no mouth parts to eat and drink, this adult female’s sole job was to mate and lay eggs.

Cecropia moth female newly eclosed from her cocoon. June 21, 2018 © Barb Elliot. Click to enlarge.

I decided to keep the moth outside overnight to see if she could attract a mate. At dusk, I put her in a wire cage with holes sufficiently large for mating to occur. A male, with its large, feathery antennae, can detect the pheromones a female emits and hone in from over a mile away.

I got up at 5 AM the next morning to check on her. A male was clinging to the cage and mating with her! The two mated all day and de-coupled just before dark. Right away she began laying eggs. I released the male so he could mate with other females.

Mating Cecropia moths. Note the male’s (on right) larger, more feathery antennae. © Barb Elliot. Click to enlarge.

During the overnight hours, she laid about 130 eggs. After she rested, I released her so she could lay more eggs and live in the wild for the rest of her short life.

Cecropia eggs – two days old. June 27, 2018.

I kept five eggs and donated the rest to several environmental organizations and a few caterpillar-savvy friends. Three of my eggs hatched on July 4^th, ten days after being laid.

My Cecropia eggs after three hatched. Note the two with exit holes chewed by the tiny caterpillars. July 4, 2018. © Barb Elliot. Click to enlarge.

Each ¼” black, spiny caterpillar chewed a hole in its leathery brown egg and almost immediately began eating the River Birch leaves I provided. Within two or three days, the caterpillars outgrew the skin of their initial first stage (instar) and molted into a second instar. Each time a caterpillar molted, the new skin was “loose” so it could continue its rapid growth. All three ate, grew, and reached the fifth instar, their final caterpillar stage.

Newly hatched Cecropia moth caterpillar – first instar. . July 4, 2018. © Barb Elliot. Click to enlarge.

First & second instar Cecropias. 9 days old. July 13, 2018. © Barb Elliot. Click to enlarge.

Two Cecropia cats molting from 2nd to 3rd instar; one still in 2nd instar. 11 days old. July 15, 2018. © Barb Elliot. Click to enlarge.

More mature 3rd instar Cecropia. 22 days old. July 21, 2018. © Barb Elliot. Click to enlarge.

Two fifth instar Cecropias and one 4th instar. 31 days old. Aug 3 2018. © Barb Elliot. Click to enlarge.

While my Cecropias were growing, I got an opportunity to raise another large silk moth. On July 13, a friend noticed a large moth at the foot of a light pole – a Royal Walnut Moth or Regal Moth (Citheronia regalis). Unfortunately, the moth was dead but had laid eggs before succumbing. This hapless moth, like countless others, was drawn to nighttime outdoor lights, but was unable to escape the lights and died.

Dead Royal Walnut Moth by light pole with eggs. July 13, 2018. © Barb Elliot. Click to enlarge.

Of about 25 eggs I kept five and donated the rest to the Academy of Natural Sciences. Just one of mine hatched and I began feeding Black Walnut leaves, one of its host plants, to the tiny fierce-looking caterpillar. This caterpillar, known as the Hickory Horned Devil (HHD), is the largest caterpillar species in North America. This species also goes through five instars before pupating. Although harmless, each stage looks scary and unpalatable, intended to make a bird or other hungry predator steer clear of such a high-protein meal.

Newly hatched Hickory Horned Devil caterpillar. July 24, 2018. © Barb Elliot. Click to enlarge.

Second instar of the Hickory Horned Devil. Aug 1, 2018. Day 9. © Barb Elliot. Click to enlarge.

Third instar of the Hickory Horned Devil. Aug 6, 2018. Day 14. © Barb Elliot. Click to enlarge.

Fourth instar of the Hickory Horned Devil. Day 20. © Barb Elliot. Click to enlarge.

Early 5th instar of the Hickory Horned Devil. Aug 16, 2018. Day 24. © Barb Elliot. Click to enlarge.

Hickory Horned Devil 5th instar, now greener with some blue near the head. Aug 19, 2018. Day 26. © Barb Elliot. Click to enlarge.

Fifth instar, Hickory Horned Devil. Some blue starting in a few spots on top of body. Aug 22, 2018. Day 30.

Hickory Horned Devil in final 5th instar colors – ready to pupate. Wikipedia image by Chris Hibbard.

Hickory Horned Devil Pupa. Winter 2018-2019. © Barb Elliot. Click to enlarge.

To my astonishment, I was raising the moth species with the largest caterpillar along with three caterpillars of the largest moth species. By the end of August, all three Cecropia caterpillars made their cocoons. My almost hotdog-sized HHD caterpillar turned into a dark brown pupa during the first week of September. This species doesn’t spin a cocoon like its Cecropia relative, but digs down into the soil to pupate and spend the winter. To simulate an underground environment. I provided an enclosure filled with crumpled paper towels, and the caterpillar pupated there successfully. When temperatures turned frigid, I moved the HHD pupa into my refrigerator for safe-keeping over the winter. As I had with their mother, I kept the Cecropia cocoons outside and waited for spring.

All three Cecropia moths eclosed – a male on May 22^nd, and females on June 22^nd and 25^th – and I released them after dark on those nights.

The second of my 3 Cecropias to eclose from its cocoon – a female on June 22, 2019. © Barb Elliot. Click to enlarge.

Unfortunately, the HHD pupa died, so that huge, spectacular caterpillar didn’t become a beautiful Royal Walnut Moth as I had hoped. In nature, less than 5% of caterpillars survive to become butterflies or moths.

A live Royal Walnut Moth. (Citheronia regalis). © Paul Scharf via dpr.ncparks.gov

Because they are active only at night, it’s rare for us to see Cecropia, Royal Walnut, or other large moths. However, they and their caterpillars are key food sources for birds and other animals and thus are important members of our local food webs. You can help keep them flying by providing native trees and shrubs that caterpillars need for food. If you have outdoor lights, use timers or motion detectors so they are not on from dusk to dawn. Of course, don’t use pesticides, which kill not just moths and caterpillars, but other beneficial insects, many of which are in steep decline. If you’d like to see these and other interesting moth species, attend a local moth night event, perhaps during National Moth Week in July, or have a moth night of your own. I wish for you a Cecropia Moth, Royal Walnut Moth, and other magnificent nighttime moth wonders!

Polyphemus Moths Live Near Me

Posted on October 26, 2017 by barb

By Edie Parnum

Female Polyphemus Moth. © Edie Parnum. Click to enlarge.

A Polyphemus moth alighted on my walkway. It was August 2016, and I had just moved to a retirement community. This cinnamon-colored giant silk moth had a wingspan of 4 1/2 inches. Each hind wing had a large eyespot highlighted with yellow and blue. It’s named for Polyphemus, the one-eyed Cyclops, who was blinded by Odysseus. Although I’m a “moth-er”, I had never seen this handsome moth before.

This summer I acquired two Polyphemus caterpillars at Mothapalooza, a mothing

Polyphemus Moth caterpillar. Photo from Wikimedia Commons by MamaGeek. Click to enlarge.

conference. They survived the 9-hour ride from southern Ohio. Once home, I fed them White Oak leaves from my community’s wooded area. They ate voraciously and pooped continuously. (Scientists call the excrement frass.) Once or twice a day I cleaned out the mesh cage and supplied them with fresh leaves. After two weeks, they stopped eating and formed their cocoons.

Twelve days later, a beautiful Polyphemus adult emerged. I knew she was a female because she had unfeathered antennae. Some friends and I released her at dusk.

Off she flew beaming out her pheromones to attract a mate. Two days later a male emerged from the second cocoon. We released him, too. Using his feathered antennae, he can “smell” a female’s pheromones from miles away.

These two moths (or others of their species) will meet up and mate. They will not eat. Their sole job is to mate. The fertilized female will lay her eggs on an oak, willow, maple, or birch.

Her eggs will hatch and become caterpillars. Birds, mammals, and other insects will eat most of them. Miraculously, a few will survive. The cycle of life will continue—cocoon, adult moth, mating, egg laying, tiny caterpillars, big caterpillars, and cocoon again. This will happen over and over, as long as we have wooded areas or yards with the essential native trees to support them.

Fall can be a good time to look for Polyphemus and other caterpillars. Many caterpillars leave the host plants where they’ve been feeding and start walking. These “wanderers” are looking for a suitable place to overwinter. Many will spend the winter in leaves on the ground; others will spin a cocoon attached to a twig.

A Polyphemus moth cocoon could spend the winter in your own yard. Never mind the cold. Go out into your yard and examine the bare branches of your native trees and shrubs. In 2012 Barb Elliot found a Polyphemus moth cocoon on a Spicebush twig. She told her story on our blog: https://backyardsfornature.org/?p=87, “A Magnificent Moth”. Maybe you, like Barb, can find a Polyphemus or other cocoon. At all times of the year, we can look for signs of nature, both active and dormant, in our backyards.

A Magnificent Moth

Posted on June 7, 2012 by barb

by Barb Elliot

When I was a ten year old kid I “saved” a Polyphemus moth my father had almost accidentally killed while pruning our hedge. Actually, I didn’t save it—in truth, quite the opposite. I captured it and put it into a collecting jar. After it died I mounted and framed it. Enamored with butterflies and moths, I then hung it in my bedroom along with the rest of my collection. Over the years I have displayed this beautiful, six-inch moth in my various homes. However, I never saw one in the wild again until this spring – more than 50 years later.

Male Polyphemus Moth (Dan Mackinnon @ fcps.edu)

On May 20th, a spectacular male Polyphemus moth just like that first one emerged from a cocoon in my yard. I had discovered the large cocoon hanging from a Spicebush twig in early March. I couldn’t tell what type of moth might be overwintering in the cocoon, but I checked it often, hoping to see what would emerge.

: Cocoon in my yard, 3/7/2012

When the time came, I almost missed it because it hung several inches from the cocoon, which appeared to be intact except for a small hole in the top. As the moth hung among the leaves, only the under wings, which look like dead leaves, were visible. I would have liked to see the more striking upper sides of the wings, but did not disturb it for a better look. This moth was to remain completely free — and in fact it was gone by the next day.

: Newly emerged Polyphemus Moth in my yard, 5/20/12

It likely flew off that night in hot pursuit of a female, using its large, feathery antenna to detect the powerful sex hormone scents (pheromones) a female emits to attract a mate. Polyphemus males can detect and fly to females that are miles away. The moths survive for about a week, living only to mate and lay eggs. In fact, the adults don’t have mouthparts and can’t eat or drink.

A Polyphemus caterpillar, however, is an eating machine.

: Polyphemus moth late stage caterpillar (buglifecycle.com)

In the five to six weeks it takes until it is ready to pupate and spin its cocoon, it increases its weight by more than 10,000 times and grows to three inches long and ¾ inch in diameter. The caterpillar then wraps itself in a leaf and encases itself in silk thread spun from its mouth or it may crawl down and spin its cocoon on the ground. A cocoon wrapped in a leaf may stay on the tree or shrub all winter as “mine” did, or it may fall to the ground in the autumn. This is an important reason not to rake up the leaves that fall under your trees and shrubs.

As a result of their nocturnal habits and since so few make it to adulthood, not many of us ever get to see these beautiful creatures. Birds and mammals search out the protein-rich caterpillars, and few caterpillars escape the many parasites that prey on them. If you provide host plants that the caterpillars eat, you can increase your chances of seeing one and help to increase their chances of survival. Polyphemus moth caterpillars eat the leaves of a variety of native trees, including Oaks (Quercus), Maple (Acer), Birches (Betula), Hickories (Carya), Walnut (Juglans), Black Cherry (Prunus serotina), and American Elm (Ulmus americana). I’m not sure which of these plants “my” caterpillar ate, as I have five of these species in my yard.

The Polyphemus moth is in the family of large showy silk moths native to southeastern Pennsylvania. Others species include the Cecropia (the largest moth in North America), Luna, Io, Imperial, Promethea, Tuliptree, Rosy Maple, and Royal Walnut Moth. These moths also eat a variety of native trees and shrubs that would make great additions to a yard.

One last thing you can do to help the Polyphemus and other moths survive and reproduce successfully is to keep outdoor lights turned off as much as possible. Any lights at night can “capture” moths, interrupt their search for mates, exhaust them, and make them easy targets for predators.

: Newly emerged Polyphemus Moth with cocoon, 5/20/12

I hope you too may have the exciting experience of seeing a Polyphemus or one of the other showy silk moths in your yard!