Giant Silk Moth: All You Need to Know in a Snapshot

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Giant Silk Moths, belonging to the Saturniidae family, are medium to large-sized moths known for their stout, hairy bodies and feathery antennae. With a wide variety of species, these moths showcase stunning color patterns and prominent eyespots adding to their mystique. For instance, the popular Luna, Cecropia, and Polyphemus moths all fall under this fascinating family.

In their short lifespan, adult Giant Silk Moths only live for a few weeks due to their small or absent mouthparts, rendering them unable to feed. The beauty of these moths has inspired curiosity and captured the attention of both professional and amateur entomologists. Their captivating appearance and unique biology make the Giant Silk Moth a truly special creature to discover and learn about.

Giant Silk Moth Overview

Types of Giant Silk Moths

Giant Silk Moths belong to the Saturniidae family and include several well-known species:

  • Cecropia Moth (Hyalophora cecropia)
  • Luna Moth (Actias luna)
  • Polyphemus Moth (Antheraea polyphemus)
  • Promethea Moth (Callosamia promethea)

These moths are known for their large size, with wingspans ranging from 4 to 6 inches.

Species Wingspan
Cecropia Moth Up to 6 inches
Luna Moth 4-5 inches
Polyphemus Moth 4-6 inches
Promethea Moth 3-4 inches

Distribution and Habitat

Giant Silk Moths are primarily found in North America and are adapted to a wide range of habitats, including:

  • Temperate forests
  • Suburban gardens
  • Mixed woodlands

Each species has its own preferred habitat. For example, the Cecropia Moth is adapted to deciduous forests, whereas the Luna Moth prefers mixed deciduous and coniferous forests.

Some notable characteristics of these moths include:

  • Large, colorful wings
  • Impressive size
  • Unique patterns on wings and body

Physical Characteristics

Wings and Wing Patterns

Giant silk moths, such as the Polyphemus moth, are known for their stunning wings. They feature:

  • Beautiful patterns
  • Rich colors
  • Eyespots to deter predators

For example, the Polyphemus moth has gray wings with large eyespots on its hind wings.

Size and Sexual Dimorphism

Giant silk moths are known for their size, with some species having wingspans of 4 to 6 inches. There is some sexual dimorphism in size, with females being larger in some species.

Key features of size and sexual dimorphism include:

  • Impressive wingspans
  • Larger females in some species

Antennae and Eyespots

Giant silk moths have feathery antennae, which are sensitive to pheromones. Females have thinner antennae compared to males.

Comparison of antennae in males and females:

Feature Male Female
Antennae Feathery, thicker Feathery, thinner

Eyespots, as seen on the Polyphemus moth, are large and distinctive markings on the hind wings that resemble eyes to scare away predators.

Life Cycle and Behavior

Eggs and Caterpillars

Giant silk moths lay their eggs during different times, depending on the species. For example, Buck moths lay their eggs in the fall, while other species may lay eggs in spring or summer. Caterpillars hatch from these eggs in a few days or after winters, and they often have bright colors and unique patterns.

  • Examples of giant silk moth caterpillars:
    • Polyphemus moth caterpillar: green with red and silver spots
    • Luna moth caterpillar: bright green with bristles

Caterpillars go through multiple stages called instars during their growth. They feed on leaves, such as those of oak trees, to support their development.

Cocoons and Pupae

After the final instar, giant silk moth caterpillars spin silk cocoons around themselves. They transform into pupae within these protective structures. Some species spend winter months as pupae before emerging as adult moths.

  • Silk cocoon characteristics:
    • Made of strong silk fibers
    • Provide protection during metamorphosis

Adult Moths

Adult giant silk moths are stunning creatures with large, beautifully patterned wings and feathery antennae. Males have large feathery antennae, while females have thinner filament-like antennae. Adult moths have small or absent mouthparts, leading to their brief life span of only a few weeks since they don’t feed during adulthood. Their primary purpose is to reproduce, and they usually fly at night to search for mates.

Comparison between male and female giant silk moths:

Male Female
Antennae Large and feathery Thin and filament-like
Primary function Locating females to mate Laying eggs

During mating, the male and female moths transfer their genetic material, and females lay fertilized eggs on suitable host plants for future caterpillars to feed and grow. This cycle of development makes up the life cycle of giant silk moths.

Feeding and Host Plants

Preferred Host Plants

Giant Silk Moths are known to feed on a variety of host plants. Their preferred host plants include:

  • Cherry: These fruit trees provide leaves that are rich in nutrients for the larvae.
  • Ash: A popular choice for Giant Silk Moths, ash trees offer large, plentiful leaves.
  • Willow: This tree species provides delicate, easy-to-consume leaves for the caterpillars.
  • Maple: The abundance of leaves on a maple tree makes it an ideal host plant.
  • Lilac: Grown for their attractive flowers, lilacs also serve as a reliable host plant.
  • Apple: As fruit trees, apple trees provide nutritious leaves for the Giant Silk Moths.
  • Poplar: Tolerant trees like poplar provide a stable environment for larvae growth.
  • Sassafras: The unique leaves of sassafras trees offer an alternative host plant option.
  • Plum: Also a fruit tree, plums support the development of these large caterpillars.
  • Box Elder: This tree species, similar to ash or maple, serves as a reliable host plant as well.
  • Gray (rare): Gray trees, although rare, can occasionally act as host plants for these moths.

Giant Silk Moths use their mouth parts, called mandibles, to help the caterpillars feed on their host plants. They typically target tree leaves and other organic materials. With their large appetite, the caterpillars consume considerable amounts of leaves which help them grow into the large, iconic moths they’re known for.

Host Plants Remarkable Features Nutritional Value
Cherry Nutrient-rich leaves High
Ash Large, plentiful leaves Moderate
Willow Delicate leaves Moderate
Maple Abundance of leaves Moderate
Lilac Attractive flowers Moderate
Apple Nutritious leaves High
Poplar Tolerant tree Moderate
Sassafras Unique leaves Moderate
Plum Nutritious leaves High
Box Elder Reliable host plant Moderate
Gray (rare) Rarely used as host plant Low-Moderate

Reproduction and Mating Behavior

Pheromone Communication

Giant Silk Moths usually fly at night. They depend on pheromones for communication during mating. Male moth’s feathery antennae are sensitive to scent and can detect a female’s pheromone emission even at great distances1.

In contrast, female antennae can be thin filament or feathery, depending on the species2. Once the male moth detects the pheromone, he is attracted to the female moth and follows the scent to her location.

Giant Silk Moths, due to their reduced mouthparts, do not have the ability to feed as adults3. Thus, their primary objective as adults is to reproduce. Bearing this in mind, here is a list of features and characteristics of their reproduction process:

  • Fly at night
  • Rely on pheromones for mating communication
  • Feathery antennae (males) to sense female scent
  • Thin filaments or feathery antennae (females)

Threats and Conservation

Predators

Giant silk moths face several predators in their lifecycle. As adults, they are often targeted by bats due to their nocturnal activity. As caterpillars, their main predators include:

  • Birds
  • Ladybugs
  • Parasitic wasps

Pests and Parasites

Giant silk moths are also impacted by various pests and parasites. One of them is the tachinid fly, which lays eggs on caterpillars, eventually killing them. Furthermore, these moths face challenges from invasive species like gypsy moths, which can outcompete them for resources and increase their vulnerability to predators.

Threat Description Example Impacts
Predators Animals that prey on Bats prey on adult moths, ladybugs prey on caterpillars
the moths and
their caterpillars
Parasites Organisms that live on Tachinid flies lay eggs on caterpillars
or inside their host
and harm them
Invasive species Non-native species that Gypsy moths outcompete native moths for resources
disrupt ecosystems or
compete with native
species

Conservation efforts for giant silk moths can involve protecting their habitat, monitoring populations, and controlling invasive species. One notable example of habitat protection is the preservation of winter hibernation sites, where moths like the buck moth spend their time in a spindle-shaped cocoon. Additionally, promoting the use of native silk moths in silk production can raise awareness of their value and encourage conservation practices.

Research and Human Interaction

Giant Silk Moths in Science

Giant silk moths, belonging to the Saturniidae family, have captured researchers’ interest for years. Their feathery antennae, used for detecting pheromones emitted by potential mates, are among their most distinctive features. Studies on moths such as these can provide insight into the olfactory perception in insects and its influence on the population dynamics.

Moths have been known to play a significant role in the natural world, particularly as pollinators. However, some species have experienced population decline, which can be attributed to various factors, including habitat loss and pesticide exposure. Research into these moths can aid in the development of conservation strategies and help to prevent further declines.

In London, a study investigating the use of perfume as a method to attract moths may have surprising implications. The paper bag technique, wherein moths are lured into a scented bag and captured for analysis, helps researchers to better understand these fascinating creatures.

When comparing moth species, it’s vital to consider key characteristics to differentiate them. An example comparison table for giant silk moths:

Feature Giant Silk Moth Other Moth Species
Size Medium to large Varies
Antennae Feathery or thin filament Usually thin filament
Adult Food Do not feed Feed on nectar
Larval Food Various plants, depending on species Various plants

Giant silk moths have several unique characteristics:

  • Feathery antennae
  • Lack of adult feeding habits
  • Stout, hairy bodies

Derived from their importance in ecology, let’s list pros and cons of researching giant silk moths:

Pros

  • Understanding their biology and behaviors
  • Informing conservation strategies
  • Assessing the impact of environmental factors on moth populations

Cons

  • Ethical concerns about capturing and experimenting on live specimens
  • Difficulty in locating and studying certain rare or elusive species
  • Limited time to study adult moths due to their short lifespan

Footnotes

  1. https://www.si.edu/spotlight/buginfo/mating

  2. https://education.mdc.mo.gov/discover-nature/field-guide/giant-silkworm-and-royal-moths

  3. https://mdc.mo.gov/discover-nature/field-guide/giant-silkworm-royal-moths

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – West Virginia is Ground Zero for Giant Silk Moths

 

Giant silkworm moths

Imperial Moth

Giant silkworm moths
Location: Ghent, WV
July 5, 2011 10:02 pm
Is it common to find 7 or 8 different types of giant silkworm moths, in one spot. I feel like I’m being over-run this week by them. You do not have enough upload slots for all the pics! Sending a few samples.
Signature: Regards, Dwayne

Cecropia Moth

Dear Dwayne,
This could hardly be called common, however, if conditions were right, it stands to reason that multiple species would eclose simultaneously.  Perhaps you have a strong light source near a woodland that is attracting the moths.  We just returned from a trip to Northeast Ohio and that included a brief road trip to Chester West Virginia to visit the Homer Laughlin Fiestaware factory which was awesome, and the surrounding hilly woods were beautiful in June.  Seems like a prime habitat for many Giant Silkworm Moths.  We would love to post your remaining photos.  Please attach the best of each species to this response and we (and our readers) would be very appreciative.  Perhaps you should consider ecotourism for your area.

Luna Moth

WV is Ground Zero – part II
Location: Ghent, WV
July 6, 2011 9:05 am
This is in reply to your request for the best pictures.
Yes, there are 2 mercury vapor lights on the property, but most of the moths seems attracted to the house. Funny thing is you can go out about every 1/2 hour and the moth that was there has been replaced by a different one. You can do this for about 2 to 3 hours a night. Critters and insects of all types. Note – the Hickory Horned Devil is laying eggs.
Signature: Regards, Dwayne

Royal Walnut Moth laying Eggs

Hi again Dwayne,
Thanks so much for supplying us with additional images.  The Royal Walnut Moth laying eggs is a nice addition, and we just posted our first photo this year of the caterpillar of the species, the Hickory Horned Devil.  We especially love your photo of the male Io Moth who appears to be winking.

Winking Male Io Moth

The blurry photo is a member of the genus Callosamia, and they can be difficult to distinguish from one another even if the images are sharp.  Our guess is a Tulip Tree Silkmoth, though we would not rule out a Prometheus Moth.  Thanks again for supplying us with this marvelous documentation which we have featured.  We are certain there are many young insect enthusiasts out there begging their parents to take them on a summer holiday to hilly West Virginia.

Callosamia species: Tulip Tree Silkmoth or Prometheus Moth???

Letter 2 – Probably Western Polyphemus Moth

 

Male Polyphemus?
Location: Spring, TX
April 3, 2012 12:52 pm
We found this gorgeous fellow when I came home for lunch today (April 3rd). Looks like a male polyphemus moth? We got several hi-res pictures of him before helping him locate a good tree to bed down in. I’d like to send all the pics to you and let you post the ones you like. A couple of samples are attached here.
Signature: Brian Legg

Probably Western Polyphemus Moth

Hi Brian,
We agree, based on the well feathered antennae, that this Polyphemus Moth is a male.  Your attached photos show both the upper wings the undersides, and they should help our readers identify Polyphemus Moths in the future.  Now that spring has arrived and much of the country is experiencing warmer weather, we expect Giant Silkmoth sightings to rise rapidly.

Probably Western Polyphemus Moth

Hi again,
This guy was so happy to pose for our cameras, we wanted to send a couple more shots of him to give an idea of the size and to show a good shot of the underside of his wings. Thanks for the quick confirmation on my original submission and keep up the great work! We love the site!
Signature: Brian Legg

Update:  July 11, 2014
In researching a posting of a Polyphemus Moth from Colorado today, we realized that this individual is most likely the Western Polyphemus Moth,
Antheraea oculea, which was recently declared a distinct species and has much darker coloration around the ocelli.  According to BugGuide is found from  “Arizona to western Texas.”

Letter 3 – Stray Giant Silk Moth: Leucanella species in San Diego CA!!!!

 

Subject: Found trembling in our office
Location: San Diego, California
June 14, 2013 8:37 am
A damsel in distress called me to remove a ”big black moth”. I found her in a corner. Had her crawl on my hand and took some pics. After that she flew off and danced around me and landed on my back and crawled up to my ear as to say ”please take me outside”. I gently grabbed her and I did what she ask.
While doing so I was telling my co-workers about your site and was going to ID the moth. I went 10 pages deep and couldn’t find her.
Thanx in advance!
Signature: Mike Coniglio

Leucanella species???
Leucanella species

Dear Mike,
We just spent considerable time trying to identify your Giant Silk Moth by browsing through the members of the genus
Automeris that are found in Mexico.  We had no success, and then we found members of another genus, Leucanella, and we believe we found your moth, however, we cannot be certain of the species.  This is a most unusual sighting, and to the best of our knowledge, Leucanella species do not stray as far north as San Diego.  See Leucanella lynx on Kirby Wolfe’s website, various Leucanella species on the Fauna of Paraguay website and various members in the genus on Saturniidae World.    We are contacting Bill Oehlke to try to get an identification.  We suspect he will likely want to document this sighting and we would request that you also provide him with access to your photos.  The big mystery for us is how did this moth get to San Diego??  Is it possible someone in your office who might raise moths is playing a joke?

Leucanella species???
Leucanella species

Bill Oehlke Confirms and Questions
Hi Daniel,
It is a Leucanella species.
There are many san Diegos in the world.
Please check to see if you can find country. Even in some central and south
American coutries there is more than one san diego.
Bill

Ed. Note: We did write back to Bill to confirm the sighting was San Diego, California.

WOW Daniel!
No, no one here in the office would do anything like that.
Our office is located at 2241 Kettner Blvd. San Diego, CA. (32° 43.658’N- 117° 10.232’W). As you can see from the Google Earth kmz file of our location, we are right under the flight path of incoming planes to San Diego International  airport. There are no direct flights from South America to San Diego. Maybe it was a stowaway on a plane?
If you need anymore, please contact me.
Thank you,
Mike

Bill Oehlke provides additional input.
Hi Daniel,
I think this is a prank with regard to location or something someone
imported from at least as far south as central Mexico.
Sometimes there can be wind assisted strays, especially if there has been a
severe storm, but San Diego California is a bit far west of the path of most
tropical storms.
It is a Leucanella female, but without knowing its true source of original
location, I would only be guessing at species.
Bill

Early Morning Ruminations:  12?51 AM Saturday June 15
2013
We can’t help but to wonder if we might be the first to report on a range expansion due to global warming, or perhaps she is only a stowaway on a plane.  Maybe one or more Leucanella caterpillars were smuggled in from Mexico.

Leucanella Caterpillar from Mexico
Stinging Leucanella Caterpillar from Mexico

 

 

Letter 4 – Polyphemus Moth in California

 

Giant Orange Moth
July 29, 2009
I was sent this photo from a friend in Chico, California. My friend said the moth was about a foot from wing tip to wing tip. I have only found one other photo online, but it has no name to it. I am curious as to what kind of moth this is.
Ann G
Chico, California

Polyphemus Moth
Polyphemus Moth

Hi Ann,
This is a Polyphemus Moth.  Charles Hogue indicates in his book Insects of the Los Angeles Basin that the species is native to the Los Angeles area.  BugGuide also has reports from California, but most of our reports come from Eastern North America.  Thanks for sending us this California documentation.  We are also going to copy Bill Oehlke on this as he is compiling comprehensive data on species distribution.

Letter 5 – Royal Moth Caterpillar

 

Subject: large caterpillar in north Tucson, aAZ
Location: Tucson, az
October 4, 2014 12:28 pm
saw this guy on the patio this morning and I had to take a picture of him. this photos taken in the northern part of tucson arizona on october the fourth around 11 am. average temperature is about 90 degrees. I thought it was a sphingicampa raspa but I’m less than 50% sure on that.
Thanks a bunch.
Signature: neil

Sphingicampa Caterpillar
Sphingicampa Caterpillar

Hi Neil,
You have correctly identified the genus
Sphingicampa, but according to BugGuide:  “Eight species occur in America north of Mexico” and they all have similar looking caterpillars.  BugGuide reports three species in Arizona, including Sphingicampa raspa, and we do not have the necessary skills to say for certain which species you encountered.

Letter 6 – Royal Moth Caterpillar

 

Royal Moth Caterpillar
Royal Moth Caterpillar

Subject: strange catepillar
Location: Tucson, AZ
October 9, 2014 8:30 am
Hi there, I woke up today (October 9) my birthday to find this guy wishing me happy birthday on my porch. Actually he was crawling through a semi deep puddle. I watched him go all over, then moved him to the park so my dogs wouldnt eat him. I searched a few sites but couldn’t find a match.
I have been in Tucson, AZ my entire life, 30 years todAy, and I have never run across one of these guys. About 2 in. Long and an inch in diameter. His spikes listen and reflect a silver color. He’s quite awesome and I’m considering it a happy birthday from Mother Nature! Thank you in advance!
Signature: J. Price

Happy Belated Birthday J. Price,
This magnificent caterpillar is a Royal Moth Caterpillar in the genus
Sphingicampa, and just last week we posted another example, also from Tucson.

Letter 7 – Unidentified Giant Silkworm

 

Unidentified Caterpillar
Hi!
I need help identifying this really neat caterpillar I found here in SW Michigan. It is about 2 1/2 inches long and seems somewhat similair to some larvea of the Antheraea family. I would like to try and raise it and was wondering if it needs to eat now and if so, what should I feed it?
Thanks,
Joanna

Sorry Joanna,
The best we can do is agree it is one of the Giant Silkworm Moth caterpillars, Saturniidae. It somewhat resembles a cecropia moth and it somewhat resembles a cynthia moth, but it doesn’t look exactly like either. We will keep trying to positively identify it.

Letter 8 – Variable Princes: Giant Silkworm Moths from South Africa

 

Moth idendification
February 8, 2010
Please can you identify this moth for me! One seems to male and the other (Bigger) female
Luka Geertsema
Pretoria, South Africa

Variable Prince female

Hi Luka,
We identified your moths as Holocerina smilax, the Variable Prince, on the World’s Largest Saturniidae Site.  According to the website, females are larger, and the Caterpillars are probably a “valuable human food source.”  You may see photos of the adult moth and variable caterpillars on the Bizland Silkmoths website.  It is not possible for us to determine from the photograph which of your images if of the larger moth, so we are unable to label the sexes.  Normally in Giant Silk Moths, the antennae of the male are more developed and feathery, but due to the position the moth assumes when at rest, the antennae are not visible.  We are going to copy Bill Oehlke on this response as he may have additional information to provide for us.

Variable Prince male

Sexing Information from Bill Oehlke
Daniel,
Thanks. Yes they are Holocerina smilax. The male is the one which has the more produced forewing apex and very triangular hindwings with acute anal angle..
Bill Oehlke

Thanx a million, attached are more pics should they be usefull. PS, the one on the bark was the female with antenae without “feathers”, the other one (male) on the green vetivar grass leaf. Is it suppose to occur in SA?
Greetings,
Luka

Variable Prince female

Yes, it is native to South Africa.  Thanks for the additional images.

Variable Prince male

More images as Promised 3
Luka Geertsema

Letter 9 – Tiger Moth from Tanzania

 

Mahale Mountains Moth
Location: Mahale Mountains National Park, Tanzania
November 10, 2011 9:00 am
Dear Daniel
I took this picture in February, in the morning, in Mahale Mountains National Park- Tanzania. I would love to know what genus (or species) this animal belongs to. This beautiful moth was rather slow moving.
kind regards
Teena
Signature: Teena

Unknown Moth from Tanzania

Dear Teena,
We are going to seek some assistance from Bill Oehlke for this identification.  Your moth reminds us of the Royal Walnut Moth or Regal Moth,
Citheronia regalis, from North America (see BugGuide), however, to the best of our knowledge, that genus and subfamily are not found in Africa.

HI Daniel thanks very much for trying, I thought maybe it was from the family Ctenuchinae, but that was as far as I could get and then I wasn’t really sure.  If it is possible I would love to know.  Warm regards Teena
Teena Payne
The Infinite Horizon

How large was this moth Teena?

Hi Daniel, I reckon about 2cm-ie wing/head length.  Kind regards Teena

Bill Oehlke provides a correction
November 11, 2011
HI Daniel,
A pretty moth but I do not know what it is. It is not a Saturniidae.
Bill Oehlke

Hi again Teena,
We are going to check with Arctiid expert Julian Donahue next to verify if this is a Tiger Moth as you suspected.  Julian may be exploring some exotic land right now, so his response may be delayed.

Julian Donahue provides some taxonomy
November 14, 2011
Nice moth! Formerly placed in the mostly African family Thyretidae, but this group has recently been considered a part of the subfamily Syntominae of the Arctiidae (or the tribe Syntomini of the subfamily Arctiinae of the family Noctuidae, if you follow the recent extreme lumping of the tiger moths with the “millers”).
The moth appears to belong to the genus Balacra or the genus Metarctia, both of which have several species recorded from Tanzania. Some of those species are relatively recently described, and I do not have at hand any of the pertinent references to key out a specimen (if indeed I had a specimen in hand).
Sorry I couldn’t be any more specific.
Julian

Dear Daniel and Julian… many thanks for your efforts…I wish I had taken more pictures of this animal- especially since it was very compliant! In all the time I was in Mahale this was the only one I ever saw.  kind regards Teena

Letter 10 – Two Giant Silkmoths from Mississippi

 

Subject: Beautiful big moths
Location: Ripley mississippi
August 7, 2015 9:39 am
Hello I live in Ripley mississippi and woke to these beautiful moths on my porch what kind are they?
Signature: S.mckeown

Royal Walnut Moth
Royal Walnut Moth

Dear S. mckeown,
Both of your moths are Giant Silkmoths in the family Saturniidae.  The redder individual is a Royal Walnut Moth and the yellow and purplish moth is a male Imperial Moth.

Imperial Moth
Imperial Moth

Letter 11 – Probably Giant Silkmoth Caterpillars in the genus Arsenura from Brazil

 

Subject: Ascalapha (Probrably)
Location: South of Brazil
November 7, 2016 7:38 am
Every year, these caterpillars came and use to stay in different species of trees. The most commum tree is the Prunus selowii. They use to stay in a big group , normally .8 m to 1,0 abovo the ground. They are very predate by hemiptera insesct, as you can see in the picture.
Totally inofensive, I means, they don´t provoque any irritation in the skin when manipulate.
Signature: Wilsonpni

Possibly Morpho Caterpillars
Giant Silkmoth Caterpillars

Dear Wilsonpni,
Though your caterpillars resemble the caterpillar of a Black Witch,
Ascalapha odorata, based on this BugGuide image, we do not believe that is a correct identification.  We are pretty certain Black Witch Caterpillars do not feed in such aggregations.  Though the color is different, your caterpillars remind us of Morpho Caterpillars from our archives.  We will contact Keith Wolfe to get his opinion.  The image of the Predatory Stink Bug nymph feeding on a Caterpillar is a nice addition to our Food Chain tag.

Olá Daniel,
Nope, sorry, these are moth caterpillars, those of Morpho appearing distinctly different.
Abraços,
Keith

Aggregation of possibly Morpho Caterpillars
Aggregation of probably Giant Silkmoth Caterpillars

Update:  November 8, 2016
Thanks to a comment from contributor Cesar Crash of Insetologia, we now believe these are Giant Silkmoth Caterpillars from the genus
Arsenura.

Predatory Stink Bug preys on Caterpillar
Predatory Stink Bug preys on Caterpillar

Letter 12 – Unknown Giant Silkmoth from China

 

Subject: moth
Location: Tangjiahe Nature Reserve, Sichuan, China
December 8, 2016 12:39 pm
This one was also photographed in Tangjiahe Nature Reserve, Sichuan, China at night sitting on asphalt road. Between tips of wings estimated to be about 60 and 80 mm.
Signature: Stefan Lithner

Giant Silkmoth from China
Giant Silkmoth from China

Dear Stefan,
This is a Giant Silkmoth in the family Saturniidae, but we cannot seem to locate a matching image online.  We will contact Bill Oehlke to see if he can provide an identification.

Update:  March 29, 2017
Thanks to a comment from Hiromi indicating that this is
Rhodinia jankowskii, we have found matching images on Photozou and Insecta.pro for verification.

Letter 13 – Unknown Giant Silkmoth Caterpillar from Chile

 

Subject:  Caterpillar
Geographic location of the bug:  Southern Chile
Date: 10/20/2021
Time: 07:30 PM EDT
Your letter to the bugman:  Hola from Chile! Here is a lovely fellow we found in our Valdivian rainforest climbing a laurel tree. He is probably around 2 inches long. I’m thinking he is in the Io moth family but he has no racing stripes. Identifying insects in Chile is difficult as there is little information available on line. Many thanks for your help!
How you want your letter signed:  Chile Expat Family

Unknown Giant Silkmoth Caterpillar

Dear Chile Expat Family,
This is indeed a Giant Silkmoth Caterpillar and it does resemble the caterpillar of an Io Moth, and you are likely correct that it is in the same genus
Automeris.  It does look remarkably similar to another Chilean caterpillar that Bill Oehlke identified as likely a member of the genus Ormiscodes.

Thanks!
I guess that entomology course I took 30+ years ago came in handy!

Letter 14 – Polyphemus Moth from California

 

Subject: Polyphemus?
Location: Contra Costa County, CA
April 16, 2014 3:27 pm
He was on the window seal at the office. I tried to get good pictures of the front and wings.
Signature: Fel

Polyphemus Moth
Polyphemus Moth

Dear Fel,
Thanks for sending your images of a male Polyphemus Moth.  We don’t get many Polyphemus images from California.  Most are from the states east of Texas and Canada.  You followup email offered to submit lower resolution files.  We can handle large files and we like the best quality available since we need to reformat every image prior to posting anyways. 

Letter 15 – Polyphemus Moth: emerged from cocoon

 

giant silk moth This cocoon was on a linden (basswood) tree.
I took it off and hung it in my garage..This is the result..I did free it, of course. I will keep the cocoon for my rec room. I have hornet’s nests, various insects, snake skins, turtle shells, etc. here. Just something I do.

Thank you for sending in your marvelous image of a Polyphemus Moth.

Letter 16 – Polyphemus Moth emerges indoors in the winter

 

Beautiful Moth
February 4, 2010
I hope that you can respond to my email in time. I don’t know what to do with this moth. I live in Cleveland and it is very cold right now. I found it in the house. I can’t let it outside. It will die I really don’t know what to do with it in the house. I feel so bad for it. I believe it just came out of its cocoon. It must have been in one of the plants that we had outside this summer. What is it? Can I keep it alive until spring, and how? (It’s only February!)
Wendy
Cleveland, Ohio

Polyphemus Moth

Hi Wendy,
Alas, even if the weather was fine, this lovely Polyphemus Moth would only live a few days.  They do not feed as adults, and only live long enough to mate.  Sadly, it will die without mating.

Thank you for responding so soon. How sad.  It is so beautiful.
Wendy

Letter 17 – Polyphemus Moth found in Canada

 

Subject: Lost Lepidoptera
Location: Kentville, Nova Scotia, Canada
January 18, 2013 8:16 am
Hello!
I rescued this Lep from in-between two sets of doors on my way into work and set it outside. I’ve never see a moth (butterfly?) this beautiful in our area. Any idea what it is?
Signature: Joanna

Polyphemus Moth

Dear Joanna,
This is a female Polyphemus Moth and this is a very unseasonal time of year for a sighting in Canada.  We can only speculate that the cocoon was somehow accidentally brought indoors, perhaps on a Christmas Tree, and the warmth caused the cocoon to hatch prematurely.

Daniel-
Thanks for the reply.  I realised after I sent the request that I probably should have mentioned that it was a picture I took over a year ago, before I realised there were sites where you could submit I.D. requests!  So thank you for the I.D.
Joanna

Hi Joanna,
Thanks for the clarification.

Letter 18 – Polyphemus Moth laying eggs

 

Subject:  Giant moth in my car
Geographic location of the bug:  Houston, TX
Date: 07/12/2019
Time: 03:04 PM EDT
Your letter to the bugman:  I was driving my kids to daycare this morning and in my rearview mirror I saw what I thought might be a leaf on my window. Then at a red light I turned around and realized it was in fact not a leaf, but a giant moth. I would just like to know what kind. Can you please help me identify it?
How you want your letter signed:  Ashley F.

Polyphemus Moth laying eggs

Dear Ashley,
It appears as though this Polyphemus Moth has laid some eggs.

Should I feel bad for removing them? I mean it’s such a beautiful moth! But i really don’t want them living in my vehicle…

You can try placing the leaves on one of the following trees identified on BugGuide:  “Larvae feed on leaves of broad-leaved trees and shrubs, including birch, grape, hickory, maple, oak, willow, and members of the rose family.”

Letter 19 – Polyphemus Moth Metamorphosis

 

what are they?
From giant green caterpillar..to giant grey moths!

These caterpillars turned into cocoons last August, we kept them out in the garden shed all winter, below zero temps and all, and they finally today turned into moths! (we thought maybe they died from too much handling, trips to school for show and tell..but they are fine! We will release them tonight.) Some photos are blurry but has my fingers in it for scale to show how big these guys are!
LaRae

Hi LaRae,
What a marvelous documentation of the metamorphosis of two Polyphemus Moths.

Letter 20 – Polyphemus Moth or Oculea Silkmoth???

 

BIG, fat, hairy moth
Location: Prescott, Arizona
September 5, 2011 11:59 am
I found this BIG, fat, hairy moth attached to the outside of my kitchen window screen one morning. He stayed there for 2 days without moving. Not sure what he was doing there, but it was the weirdest thing. I’m guessing he’s a species of silk month, but would love to know more.
Signature: Dear Curious

Polyphemus Moth or Not???

Dear Curious,
At first we were going to write back to you that this was a Polyphemus Moth,
Antheraea polyphemus, a species that is found in all 48 lower United States, however, we had second thoughts on our identification because a closely related species, the Oculea Silkmoth, Antheraea oculea, is found only in Arizona and generally at higher elevations, making Prescott a possible habitat conducive to the Oculea Silkmoth’s needs.  The main distinguishing feature between the two species is the coloration that is visible when the wings are opened, hence our reluctance to identify a species.  Here is a closed view of a Polyphemus Moth from BugGuide, and one from an Oculea Silkmoth also from BugGuide.  We can tell you for certain that your individual is a male because of his antennae. 

Awesome!  Thanks for the quick reply.  I never saw this thing with its wings open – but the second one you mentioned (Oculea Silkmoth) certainly looks like my moth!

Letter 21 – Polyphemus Moth Ovipositing

 

Subject: Gorgeous Specimen
Location: Jacksonville Florida
April 17, 2013 5:06 am
Can you please identify this specimen? I am presume it is a moth based on the ’fuzzy’ antenna.
Signature: Danno

Polyphemus Moth
Polyphemus Moth

Dear Danno,
This lovely moth is the widest ranging North American Giant Silkmoth, the Polyphemus Moth.  It is wonderful that one of your images has captured this female in the process of ovipositing.  Hopefully she had a chance to mate.  Giant Silkmoths do not feed as adults, and they only live long enough to mate and produce a new generation.  The male Polyphemus Moth has more feathered antennae so that he can locate the female by the pheromones she releases.

Polyphemus Moth Laying Eggs
Polyphemus Moth Laying Eggs

Letter 22 – Polyphemus Moth: Tragedy Averted

 

A Polyphemus Story
Hey WTB,
love your website, I usually come on a few times a week to see the new additions to the site. Well, I finally have something to send in myself! It started in late August, of 2007, when my dad found this huge green caterpillar from the yard. It was nearly as long as someone’s hand, and fat like a sausage. We’d never seen caterpillar’s around here except for cabbage butterflies, so my sister and I were excited to see one like this. My dad put it in a bug jar, as I went online to your site to try and figure out what exactly we had. We thought it could possibly be a Luna moth, or something similar to the species, based on the caterpillar pictures on the site. Just moments after finding that out, the caterpillar began to spin a cocoon! By the next day, it was sealed up tight in the rock-hard cocoon, and we transferred it to another container, and put woodchips and grass clippings on the bottom so it would be like the environment the cocoon would normally be in outside. We kept it in the garage though, so it wouldn’t hatch too soon being in a warm house. For the first few weeks, we could tap on the side of the container, and it would scratch -rather loudly- back at us. My mom would leave the container outside when the weather was nice, and brought it back into the garage when the snow started falling. Living in Michigan, that could be anytime between Fall and Spring. It was halfway through winter, and my mom had pretty much given up hope that it was still living. Come Spring, about two months ago in March, she and my sister decided that the moth had died, and they were going to ‘cut the cocoon open and see what was inside’. I wasn’t home at the time, or I would have stopped them, because I remembered reading that the moths often stayed in their cocoons over winter.
My sister even videotaped the whole process of trying to cut a slit in the cocoon with a pair of sharp scissors, but my mom was careful not to damage whatever was inside. It turned out to be much stronger than they thought. But they finally did get it open, and shrieked in surprise (I have the evidence on video), when they saw a wiggling brown thing inside of it. My mom taped it back together, hoping that would keep it okay. Of course, when I found out I freaked out, thinking they had just murdered our yet-unhatched friend.
So now, it’s May 19th, and I walked into the garage, home from school. I glanced down at the container as I usually did, even though I was suspecting the moth might not come out now, but I was surprised. Something was hanging from the ceiling in the container, and I ran inside and got my mom and sister. It turns out we didn’t have a Luna moth, but it was just as beautiful. A male Polyphemus moth, I think. We were so excited it had actually hatched, I snapped some photos and immediately started writing to you! Well, I hope you enjoy the pictures and our moth story. Love your website!
Rachel G.
(I attached two pictures, one of the moth and one of it and it’s cocoon)

Hi Rachel,
Thanks for sending us your chilling account of a near Polyphemus Moth tragedy.

Letter 23 – Polyphemus Moths attracted to one another!!!

 

Please Identify
Bugman,
I found this butterfly or moth outside my house on an Azalea bush. It looks as if it had just emerged. I looked through your pages and countless other sources but could not identify it. Can you please help me. Thanks.
grem
Baton Rouge, LA

Dear Grem,
Thanks you for sending in the wonderful photo of Polyphemus Moths, Antheraea polyphemus. You are correct that they are newly emerged as these Giant Silkworm, or Saturnid Moths only live long enough to mate and lay eggs. The pheromones are working strongly to have brought this pair together.

Letter 24 – Portrait of a Polyphemus Moth

 

Polly Polyphemus Poses for Proper Portrait
What’s That Bug is the coolest site I’ve found this year! Nice work! After perusing your many great photos I find your contributors seldom get the lepidoptera to sit for proper portraits. Fortunately I have on hand many stunning portraits of Polly, the polyphemus moth who brightened our Michigan winter. Check the story on
http://detroitsubway.com/images/polyphemus/PolyphemusMoth.html
She emerged by surprise in January from a larva collected on our front lawn last August. For two weeks she graced our household, clinging passively to our tamarind tree by day and raising hell by night, laying eggs on our windowsills and draperies. I think she’s a stunning specimen, spanning over 6" as you can see in one shot on the website.
Karl
Sterling Heights, MI

Hi Karl,
Thanks for your fascinating story. I hope our readership doesn’t crash your website with all the traffic. Your portrait of Polly reminds us of a Rembrandt painting.

Letter 25 – Possibly Oculea Moth

 

Subject: moth
Location: Northern Arizona
July 21, 2017 4:02 pm
what kind of moth is this?
Signature: Connie

Possibly Oculea Moth

Dear Connie,
This is probably a Polyphemus Moth, a beautiful moth with startling eyespots on the underwings.  If your submission had come from any state other than Arizona, we would be very confident with that identification, however, parts of Arizona and New Mexico are the range for the Western Polyphemus Moth or Oculea Moth, that is described on BugGuide as being:  ” similar to A. polyphemus, but darker and with more markings around the eye spots. ‘Upperside of wings is tan, sometimes with a yellowish or reddish tint. Forewing margin is the same color as the basal area; submarginal line is black. Rings around the eyespots are orange, blue, and black. Underside has contrasting rust, brown, and white markings.'”  We would need to see an image of the open wings to make a more definitive identification.

Daniel,
Thank you for your prompt response.  After studying the pictures of each, I believe the Oculea Moth is the closest match. He is gone now so I cannot get anymore pictures. I live in Show Low, Arizona which is located in the White Mountains.  The elevation here is 6350.
Again than You,
Connie

Thanks for the additional information Connie.  Oculea Moths do tend to be found at higher elevations.

Letter 26 – Royal Erbessa or Not???

 

Subject: Erbessa regis???
Location: Amazon Manu Lodge, Madre de Dios, Peru
March 14, 2013 3:41 pm
Hi again!
Another Peruvian moth. Found a look-alike on the internet, Erbessa regis, but mine is much paler! Can the Erbessa regis be this pale?? Or is it another species?? Please help me out!
Thanks.
Photo taken November 10, 2009.
Signature: Kristian

Royal Erbessa, we suppose
Royal Erbessa, we suppose

Hi Kristian,
Your moth looks very similar to the Royal Erbessa posted on the Moths of the Andes website, except for the paler coloration.  We hope your realize that we run our website as a labor of love and that there are no entomologists, nor anyone with a credible scientific background on our staff.  If you want definite and accurate species identifications for your numerous and lovely photographs, we strongly urge you to seek professional assistance.  Meanwhile, we will continue to post as many of your photos as possible, but we cannot be held responsible for any misidentifications our staff provides.  Our main mission is to share our appreciation of the lower beasts with our readership and also to stress the interconnectivity of all life forms on our fragile planet.  We are often content with providing a family identification.  As you are probably well aware, getting accurate species identification from the internet can often be a laborious and unfulfilling task since there is a proliferation of erroneous information on the internet.  Perhaps one of our readers with a greater knowledge of Andean moths will write in with a comment confirming or correcting your identification.

Letter 27 – Royal Moth Caterpillar: Sphingicampa species

 

Subject: spikey green caterpillar
Location: Tucson Arizona USA
January 16, 2013 2:05 am
Hey bug man, found this little guy right outside the door of my house. Picked him up and placed him in the garden, but I still want to know what it is! Haven’t seen him around since. Think it’s the Hubbard’s Silkmouth, but I’m not sure. My roommate suggested this sight and is a huge fan. Thank you for any input you can give!
Signature: Mad in Tucson

Sphingicampa Caterpillar

Dear Mad in Tucson,
This is a Royal Moth Caterpillar in the genus
Sphingicampa, formerly the genus Syssphinx According to BugGuide:  “Eight species occur in America north of Mexico” and the caterpillars all look quite similar.  The Arizona Beetles, Bugs, Birds and More website has nice photos of two species.  The Hubbard’s Small Silkmoth is one of the members of the genus and is a very likely candidate for your species.

Letter 28 – Royal Moth from Costa Rica

 

Subject: A moth that reminds me of a golden retriever
Location: Guanacaste province, Costa Rica
September 15, 2016 5:20 am
This one has stumped me for a few days, it appeared on my terrace in September in North- pacific Costa Rica.
A friend tells me it’s an imperial moth but their range stops about 900 miles north of where this picture was taken (and pictures of imperial moths don’t show a big fluffy head or striped body).
Any guidance would be appreciated!
Signature: EC

Royal Moth: Citheronia lobesis
Royal Moth: Citheronia lobesis

Dear EC,
We believe we have correctly identified your Royal Moth as
Citheronia lobesis, but we would like to verify that with Bill Oehlke.  We would also request that you allow Bill to post your images to his own very comprehensive web site.  You can compare your images to the ones posted at the Smithsonian Tropical Research Institute site.

Royal Moth
Royal Moth

Bill Oehlke Responds
Yes, lobesis, probably a female. Please also get date if you can???
Bill

THanks a million!
Sure you can post. Looking forward to Bills response!
Compared to the smithsonian pic it looks like a match! Thanks!
Elizabeth

 

Letter 29 – Spiny Oak Slug Caterpillar and Polyphemus Caterpillar

 

Subject: Caterpillar
Location: Northeastern Houston TX
October 17, 2016 5:29 pm
I trimmed some branches off my small oak tree and when picking up the branches I felt a sting similar to a wasp sting in my hand. Within 30 minutes I was in blinding pain raidiating up my arm like my hand was on fire and broken and pain in the armpit. Pain lasted about 12 hours and 2 days later my arm is still sore. I’ve begun searching the oak for possible culprits, I’m leaning towards and asp caterpillar but haven’t found one yet. Instead I have found these two beauties. I’m going to keep searching. I’m thinking the one is a Polyphemus caterpillar. The other maybe a spiny oak slug?
Signature: Theresa in TX

Spiny Oak Slug Caterpillar
Spiny Oak Slug Caterpillar

Dear Theresa,
While one of your caterpillars is a harmless Polyphemus Moth Caterpillar, which you can verify by comparing to this BugGuide image, your other caterpillar is definitely a Spiny Oak Slug Caterpillar,
Euclea delphinii, which is also pictured on BugGuide.  There are many species of Stinging Slug Caterpillars in the family Limacodidae, and of the Spiny Oak Slug Caterpillar, BugGuide indicates:  “Caution, this is a stinging caterpillar. ”

Polyphemus Caterpillar
Polyphemus Caterpillar

Letter 30 – Splendor in the Grass!!!: Mating Polyphemus Moths

 

mating Polyphemus Moths
Hello all. It’s Spring in North Carolina, and I just found these rascals enjoying the mild weather beneath my garden hose box. I’m pleased and relieved that I didn’t find the copperhead snake that I’d expected when I originally spotted the edge of one wing beneath the box. Love is in the air, and within 1 inch of the ground. Keep up the good work.
Craig in Central NC

Hi Craig,
Thanks for sending such a gorgeous image of mating Polyphemus Moths. “Though nothing can bring back the hour Of splendour in the grass,” at least there will be a new generation of Polyphemus Moths thanks to this romp on the lawn.

Authors

  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

    View all posts
Tags: Giant Silk Moth

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31 Comments. Leave new

  • The edibility question:
    From what I’ve read, there are roughly 40 to 60 species of Saturnid caterpillars consumed in Africa [at least in terms of documented species]. I learned that Holocerina agomensis larvae are (or perhaps were) consumed in Zambia. Likely smilax is also. Yet I’m curious to know where that quotationed phrase came from.

    Best,

    Dave
    http://www.smallstockfoods.com

    Reply
  • it’s possible that that “40 to 60” number may shrink when more focused research is applied, and as implied, it’s likely that consumption of various insects is decreasing around the world.

    Reply
  • Because I was “told” that this is called a “Snakehead Moth”, and because I can TOTALLY see why, I am calling it that. But searching for ‘that’ name, got me no where here except to this post, which, I very well enjoyed~ But, I’m wanting to post this pic of my “Snakehead Moth” that I discovered with part of it’s wing missing, conclusion…? It’s days of “any kind of romp in the grass” are over. But would really like to know for sure what it is… since I personally have never seen one before.

    Reply
  • Thank you so much! Silly as it may sound, you just made my day!! :}
    She is beautiful!!

    Reply
    • Hi Danno,
      We are thrilled to hear it. If she mated and the eggs are viable, they should hatch in a week or so. The caterpillars feed on a wide variety of plants, including “birch, grape, hickory, maple, oak, willow, and members of the rose family” according to BugGuide: http://bugguide.net/node/view/427 . You should try raising some of the caterpillars or releasing them on the appropriate food plants, and if the plants are in your garden, you can watch them grow.

      Reply
  • Thank you so much! Silly as it may sound, you just made my day!! :}
    She is beautiful!!

    Reply
  • Julian Donahue
    June 15, 2013 8:46 am

    The “trembling” behavior and the excellent condition of the moth may mean that it just emerged from its cocoon. The caterpillar may have pupated in someone’s luggage or commercial cargo or produce and hitchhiked from a tropical location as an undetected stowaway. (I personally know of a Caligo owl butterfly and a tropical ctenuchid moth that were found flying in a Lansing, Michigan supermarket! They had most likely hitchhiked as pupae on bananas.)

    Reply
  • Thats cali-cool moth!!

    Reply
  • Love your websigth, my granddaughter and i make use often.

    Reply
  • I live in Ramona, CA (San Diego County) and have found a total of 5 of these moth caterpillars devouring my potted vegetable plant leaves. Man they can wipe all of the leaves out in a single day. Never seen an adult moth in the wild here. Let me know if you want me to send a photo of one of these caterpillars. Not sure how to do that on this site.

    Reply
  • Daniel, I recieved simmilar images and my opinion was Arsenura. I dunno if it’s correct, but it must be some kinda moth, cause there are some cocoons in our images: http://www.insetologia.com.br/2015/11/lagartas-gregarias-e-casulos-em-sao.html#comment-2989619991

    Reply
  • Does a caterpillar that large survive being lunch by a little bug like that?

    Reply
  • I can confirm that this moth is in San diefo, CA. Near alpine in San diego County. I have also found them at my house in alpine. If you want pictures I can email to them.

    Reply
  • Rhodinia jankowskii ?

    Reply
  • I think I might have one of these little creatures. Mine looks a lot like this, but his body is red and white striped going around his body, not horizontally. I am sad to say that my cats got a hold of him before I was able to rescue him. I kept him out of harm’s way as best I could, but I could not let him go back outside on his own. I notice that he quivers his wings. I wonder if that is a way to call the females to mate with him. I learned that their adult life is only four days and during that time they do not eat. I matched him with other pix on the internet and he was called a Giant Silk Moth. I live in Oregon and I have never seen such a creature. He is a beauty; I hope they are not going extinct as suggested here.

    Reply
  • Six years later, another one attached itself to my house. Appears to be the same species as the last one. This time I was able to get a photo of the wing open but I’m not sure how to attach them.

    Reply
  • I presume normal (for global warming) range expansion. This species is very similar to that of the Io Moth which I remember well in Ohio.

    Reply
  • Thank you for this post, helped me identify two giant moths I was surprised to see during the day outside a grocery store (strong lighting outside a wooded area) in Warren County, Virginia: Imperial moth and Royal Walnut Moth.

    Reply
  • I saw this same moth today also in Chico CA. He’s been outside the entrance of my work all day. He’s a beauty.

    Reply
  • Arne Christiansen
    January 20, 2020 4:34 pm

    … and I think we found one on a stucco wall, somewhat protected from windows in weather mid-60s. Lovely sight to be sure.

    Reply
  • Hello, I had a cocoon of the Polyphemus moth, from October to March 16th it hatched. It is beautiful. But it is not quite spring, it is 36* outside, actually called for freezing overnight. It’s supposed to warm up in the next few days. I realize it is supposed to breed. It is male with the lg antenna. I would like to put it on the tree that I found it under.(it was blown out of the tree in a wind storm) I’m sure it would have parished. My dilemma is it safe to let it out with these temperatures. It’s supposed to get in the 50s, but drop to the high 30s overnight. What to do?

    Reply
  • Can I send you some amazing moths I have amazing pics of this year, one being this giant silk moth

    Reply
  • Another is the best picture and coloring of any leopard moth pic I have seen

    Reply

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