Friday, August 25, 2023

Polyphemus - Magnificent Moths - A Three Month Experience

The summer of 2015 was filled with myriad wildlife experiences for me.  I monitored and tended to 15 "bluebird" nest boxes I had set up in the spring of 2014.  The 2015 season saw 90 eggs laid by birds from five species with 70 eggs hatching and 69 young birds making it to their first flights. I crossed paths with lots of other creatures, too. Among these were snakes, skinks, turtles, frogs, toads, salamanders, and lots of insects including beetles, butterflies, and a bonanza of moths that were attracted to the lights in "The Moth Pit" that I setup at the rear of our home.  

Polyphemus Moth 

(Antheraea polyphemus)

One of the highlights of the summer was observing Polyphemus Moths and caterpillars.  On a rainy May 21st I found this female moth clinging to a second floor window at the lab.  Her abdomen is quite stout and undoubtedly filled with eggs.

May 31st 2015
But the real fun started for me early in the morning of May 31st when I went down to check the sheets in the "Moth Pit". I was photographing several small moths on the first bed sheet when I turned to check the second sheet.  I was startled when I caught sight of something huge...was it a bat? There it sat, a huge and beautiful moth from the Giant Silk Moth family with a distantly related pink and yellow Rosy Maple Moth (Dryocampa rubicunda) nearby (upper right of photo).  This female Polyphemus Moth got me started on a summer-long project that stretched to the early days of September. That project is chronicled in this very lengthy post.

I placed my hand near the female moth's head and was delighted that she crawled up on my fingers where I could take a better photo and study her more closely. Notice her thin and slightly feathered antennae.  I was astonished to realize that the center of her four "eye" spots were transparent like the cellophane wrappers of certain hard candies. You can see the pinkish color of my finger showing through in the lower right eye spot.

Soon she fluttered down to my pants leg where she perched for a while.  I read online that if a female has moved from where she eclosed (emerged) from her cocoon, that she has probably already mated.  It is apparently common that the female moth will mate before she takes her first flight. 

I also read that it is possible to collect the moth's eggs by placing the female moth in a paper bag for a few days with the top folded over.  So I transferred the female Polyphemus Moth to a brown paper bag from a local grocery and folded over the top.  I released her a few days later after finding nearly 70 sesame seed sized eggs glued to the bottom and sides of the paper bag.  

June 13th 2015
(Hatching Day)

On June 13th the first of the eggs began to hatch.  You can see where the tiny caterpillar has eaten some of its egg shell, its first meal.  Two eggs near the center are becoming transparent and will soon hatch.  Many of the other 25 eggs in this photo will hatch as well.

Here on the left is a cluster of four first instar caterpillars freshly hatched with more unhatched eggs on the right. 

One of the newly hatched caterpillars with its tiny bristles rests in the palm of my hand.

The same day-old caterpillar marches off along my thumb. How can this little larvae become a enormous caterpillar in less than two months?  I read that a newly hatched caterpillar can consume 86,000 times its hatching weight in the seven or eight weeks prior to spinning its cocoon.

This is the same Polyphemus caterpillar heading off across my knuckle!

I transferred the newly hatched caterpillar to a freshly plucked Sugar Maple leaf (Acer saccharum) and it immediately began to look for a dining spot.

June 20th 2015
(7 days after hatching)

At seven days since hatching these five little caterpillars were hungrily munching away on some White Oak leaves (Quercus alba) that I plucked from backyard trees.

These are second instar caterpillars which have already molted once as they had gotten too large for their first "skin".  I am speculating that the white fuzz on their bristles are fibers that came from the paper toweling I had placed on the bottom of their clear plastic storage container to control excess moisture in their enclosure.

June 28th 2015
(15 days after hatching)

At fifteen days after hatching these caterpillars have entered their third instar and are nibbling through Sugar Maple leaves.  The fuzz that was stuck to the bristles of their previous "skins" is gone. 

The caterpillars have six rows of orange tubercles along their backs and sides. Each tubercle is arrayed with several bristles. 

Just after a caterpillar molts or sheds its skin, its head will look quite large compared to the size of its body.  As it eats more and more, its body gets larger which makes its head look smaller by comparison.

July 1st 2015
(18 days after hatching)

On July 1st, I awakened at 4:00 AM and while I was up I checked on the caterpillars.  Finding many of their leaves nearly consumed, I ventured out at this early hour to procure more foliage for their larder.  These are hungry little babies, 

At eighteen days since hatching these four buggers have made serious inroads on this Sugar Maple leaf.

This is an enlargement of the photo above.  In the middle of the photo you can barely make out the brown color that is the leading edge of the caterpillar's head.

I believe these are late stage third instars as their heads are pretty small compared to their enlarge girth.

July 3rd 2015
(20 days after hatching)

It won't be many days before these guys will have to molt again into their fourth instar.  A series of four photos follow:

July 6th 2015
(23 days after hatching)

The caterpillars continue to be voracious feeders and keep me busy looking for Sugar Maple boughs.

July 9th 2015

(26 days after hatching)

A series of five photos follows of one of the larger caterpillars at nearly four weeks old.

July 17th 2015

(34 days after hatching)

Polyphemus Moth caterpillars feeding on Sugar Maple leaves

This is the largest of the 18 caterpillars remaining from the moth that laid about 70 eggs at the end of May.

July 22nd 2015

(39 days after hatching)

One of the Polyphemus caterpillars still chomping away on Sugar Maple leaves and still growing.

July 25th 2015

(42 days after hatching)

The next two photos are of one Polyphemus caterpillar in the late stages of shedding the skin has outgrown. These guys are now six weeks old.


One of its broodmates has completed casting off its outgrown skin.

August 9th 2015

(57 days after hatching)

These area the last six Polyphemus Moth caterpillars yet to construct their cocoons. Twelve of their broodmates have already spun their cocoons.

August 13th 2015

(61 days after hatching)

This is an August update on the Polyphemus Moth caterpillars as they form their cocoons. I have constructed a "cage-like" enclosure to protect the 18 cocoons from predators (read - squirrels) and placed this on the deck so the cocoons will be exposed to the weather. I hope to see which ones will emerge as adult moths before fall and which ones over-winter and "eclose" next spring.

This is the last caterpillar to construct its cocoon. You can see some of the "random" strands of silk as it tests out its surroundings for the leafy material is has to work with. (around 10 AM)

A few hours later the caterpillar has pulled a couple maple leaves into the periphery of its cocoon. (around 6 PM)

The caterpillar is still working to close in the back end of its cocoon. (around 6 PM)

The caterpillar's head and back end are still exposed. (around 6 PM)


A couple hours later (around 11 PM) the framework is done and the caterpillar is filling in the open spaces with silk.

August 14th 2015

(62 days after hatching)

The next morning the silk covering looks to be complete. (around 7 AM)

The next morning the silk covering looks to be complete. (around 7 AM)

The next morning the silk covering looks to be complete. (around 7 AM)

August 27th 2015

(75 days after hatching)

This is the first Polyphemus Moth to eclose (emerge from her cocoon) inside the "cage" I made for the 18 caterpillars that made it to the cocoon stage.
I found the original mother moth on May 31st. She laid about 70 eggs over the next two days. About 30 of the eggs hatched out beginning on June 13th. They fed on maple leaves that I supplied every day or so for about 50 days. About 12 caterpillars did not make it through the process and the 18 remaining caterpillars began spinning cocoons the last day of July through about August 14th. This first female moth spent about 20 days in her cocoon before emerging. When I found her last night, she had already laid 20 or more eggs.

This is the second Polyphemus Moth to emerge, also a female. She is resting on the maple branch that I had attached the cocoons to with floral wire.

These are the two female Polyphemus Moths resting at the bottom of the "cage". You can see some of the eggs that were laid on the maple branch at the bottom of the picture.

This is the cocoons from which one of the first two female moths emerged. I used freebie return address labels to note the date that the cocoon was spun and the order from 1 to 18 in which they were spun. The green floral wire is how I attached the cocoons to the maple branches.

The remains of the pupal skin can be seen inside the cocoon. The eclosing moth uses a special fluid to soften the silk at the end of the cocoon. Once the silk is softened, the moth uses stiff "spurs" on either side of its thorax to burrow its way out as is rotates its body in a circular fashion.

Here are more eggs that are attached to the 1/2" hardware cloth that forms the perimeter of the cage.

The first male to eclose rests as he waits for his wings to stiffen. The male's larger feathery antennae make it easy to determine its gender.

The first male Polyphemus Moth with its fully expanded wings rests on the bottom of the cage.

The first male resting on the floor of the deck.

The first male Polyphemus Moth rests on my finger.

To my astonishment I found this "wild" male Polyphemus near the porch light on the deck. He was apparently attracted by the first female Polyphemus Moth to emerge. The male moth can detect the pheromone scent of a female from as far away as two mile and fly to her.

The "wild" male Polyphemus is a bit larger than the first of my male moths to eclose. Their colors are nearly identical.

The "wild" Polyphemus Moth is as big as my hand.

Around midnight I found a third female Polyphemus moth emerged from her cocoon and with her wings well expanded.
The next few night could be interesting!

August 30th 2015

(78 days after hatching)

About 5:30 AM on Sunday morning I found another "wild" male Polyphemus Moth on the siding near the "cage" on the deck. His hind wings are partially covered by his fore wings hiding most of his two big "eye spots". As I was taking a few photographs I was suddenly aware of something flying over head. A second "wild" male was homing in on the pheromonal perfume of the two recently emerged female moths in the cage.

These are the third and fourth female Polyphemus Moths to emerge from their cocoons. They were resting at the bottom of the 5 gallon bucket that forms the base of the cocoon cage. They are one and two days old and obviously have been releasing their tantalizing pheromones. It is possible that they have already mated.

These are the amazing feather-like antennae of the first "wild" male moth of the morning. These structures have a large surface area that is used for detecting the specific molecules that constitute the pheromone released by the female of the species. I have read that a male Polyphemus can detect the fragrance of a female who is two miles away or more.

The second "wild" male Polyphemus Moth hovers as he tries to "follow" the chemical trail of the enticing pheromone of the females in the "cage". This is at least the second arrival of this male moth. He had flown off for a few minutes, but fluttered back for a another attempt at locating the females. I've read that the male moths usually seek out the females as early as 4 AM and if they have success with mating will stay together for much of the day.

The male reorients himself as the invisible pheromones waft in the slight breeze of the cool morning air.

He hovers and flutters more slowly as he approaches the goal of his short-lived adult life. These moths live for a week or less. During metamorphosis the mouth parts of the voracious caterpillar stage are lost and the adult moths of this species are not able to feed. Mating and laying eggs is their sole endeavor.

His remarkable antennae have led him to the temporary home of the two female moths. I did not see an actual mating occur. Perhaps earlier in the night, the first male (or others that I did not witness) had already been successful with the two female moths.

I read that "as little as one molecule of scent in a cubic yard of air is sufficient to cause the male to fly in pursuit of its source. He needs both antennae to do this. With only one, he cannot establish direction, but with two he can judge on which side the scent is stronger and so fly steadily towards it." 

The sky is beginning to lighten and after a few minutes he takes to the air to find a secure place to spend the day. There are birds and squirrels out and about by day. Perhaps he will return in the early hours of tomorrow morning.


Adult: large, brown, with a small round eyespot near the middle of the forewing, and a huge round or elliptical eyespot near the middle of the hindwing. Males (here) have much smaller bodies but much larger and more feathery antennae than do females (here). There is a lot of variability in this species.

Larva: body large, bright green, with red and silvery spots below setae, and oblique yellow lines running through spiracles on abdomen; diagonal streak of black and silver on ninth abdominal segment; head and true legs brown; base of primary setae red, subdorsal and lateral setae have silver shading below; end of prolegs with yellow ring, and tipped in black.

Widespread in North America: southern Canada southward. Most widespread North American saturniid: found in all Canadian provinces except Newfoundland. Found in virtually every one of the continental United States.

Deciduous forests, orchards, some wetlands. Adults (imagos) of both sexes frequent at lights.

In southern United States, adults fly April–May and July–August (2 broods); in northern part of range, adults fly from May to July (1 brood).

Larvae present March to November

Larvae feed on leaves of broad-leaved trees and shrubs, including birch, grape, hickory, maple, oak, willow, and members of the rose family.

Adults do not feed.

Any and all comments are welcome.