Giant silk moths, belonging to the Saturniidae family, are known for their impressive size and captivating appearance. These moths, which include species such as the Cecropia, Promethea, Polyphemus, and Luna, can have wingspans measuring between 4 to 6 inches.
Understanding the lifespan of these fascinating creatures is essential for appreciating their unique characteristics. Adult giant silk moths have a remarkably short life, primarily due to their reduced or absent mouthparts which prevent them from feeding.
Life Cycle of Giant Silk Moths
Egg Stage
Giant silk moths, such as Cecropia, Promethea, Polyphemus, and Luna, belong to the family Saturniidae. The egg stage starts when the females lay their eggs on a suitable host plant. This stage usually lasts around 1 to 2 weeks, depending on the species.
Caterpillar Stage
The caterpillar stage is the larvae phase of the moth’s life cycle. During this stage, the caterpillars undergo several molts or instars, experiencing significant growth.
- Larvae – During the larval stage, caterpillars consume large amounts of foliage, which aids in their growth.
- Instar – The stages between molts are called instars, and giant silk moth caterpillars usually go through 5 instars.
- Molts – Molting is the shedding of the caterpillar’s skin, allowing them to grow larger.
Cocoon Stage
Once the caterpillar has completed its 5 instar stages, it enters the cocoon stage, where it will metamorphose into an adult moth. Some species create cocoons on the ground, while others may do so in trees. The cocoon period usually lasts for 2-3 months, or until environmental conditions are favorable.
Adult Stage
In this final stage, the adult giant silk moth emerges from its cocoon. Adult moths have a few notable characteristics:
- Large size – Some giant silk moths have wingspans ranging from 4 to 6 inches.
- Short lifespan – Adult moths live only for about 1-2 weeks, during which they don’t eat, as their mouthparts are small or absent.
- Feathery antennae – The males have feathery antennae to locate females for mating, while female antennae are often thinner.
| Stage | Duration | Key Features |
|---|---|---|
| Egg Stage | 1-2 Weeks | Laid on host plants |
| Caterpillar | Several Weeks | Consumption of foliage, molting, and growth |
| Cocoon | 2-3 months | Metamorphosis |
| Adult | 1-2 Weeks | Large size, short life, and reproduction |
Notable Giant Silk Moth Species
Polyphemus Moth
The Polyphemus Moth (Antheraea polyphemus) is a remarkable species of giant silk moth native to North America. These large moths have unique features, such as:
- An eyespot on each wing, resembling an eye to deter predators
- Feathery antennae for detecting pheromones from potential mates
Some typical host plants for Polyphemus caterpillars include cherry and ash trees.
Luna Moth
Another fascinating species is the Luna Moth (Actias luna), which can be found from Canada to North America. Key characteristics of Luna Moths include:
- Striking green wings with distinctive eyespots
- Long, elegant tails on their hind wings
- A preference for host plants like sassafras and lilac
The Luna Moth has connections to Greek mythology, specifically through its scientific name that originates from the Roman goddess of the moon.
Cecropia Moth
The Cecropia Moth (Hyalophora cecropia) is the largest native moth in North America, showcasing sexual dimorphism and beautiful wing patterns. Some interesting facts about Cecropia Moths are:
- Males have larger, more feathery antennae than females for detecting pheromones
- Their preferred host plants include poplar, sassafras, and lilac
Cecropia caterpillars spin a spindle-shaped cocoon, which they inhabit until metamorphosis. The moth’s name, cecropia, is derived from Cecrops, the mythical founder of Athens in Greek mythology.
| Polyphemus Moth | Luna Moth | Cecropia Moth | |
|---|---|---|---|
| Size | Large wingspan | Medium wingspan | Largest wingspan |
| Eyespots | Prominent on wings | Smaller on wings | On wing tips |
| Antennae | Feathery, pheromone-sensitive | Shorter, less feathery | Males have larger, feathery antennae |
| Host Plants | Cherry, ash | Sassafras, lilac | Poplar, sassafras, lilac |
Appearance and Anatomy
Wings and Wingspan
Giant silk moths, belonging to the family Saturnidae, have impressive wingspans, ranging from 4 to 6 inches. Their large wings consist of:
- Forewings: The front pair of wings
- Hindwings: The back pair of wings
Some examples of giant silk moths with large wingspans include:
- Cecropia moths
- Luna moths
- Polyphemus moths
Color Patterns
The color patterns on giant silk moths help them blend into their environment and deter predators. Common colors found on their wings and bodies are brown and green. For instance, the Luna moth has bright green wings with brown edges, while the Polyphemus moth has brown and tan patterns on its wings.
Antennae and Senses
Adult silk moths have large, feathery antennae that enable them to detect pheromones released by females over long distances. In some species, males can even sense these pheromones from up to three miles away.
Sexual Dimorphism
In many giant silk moth species, there are visible differences between males and females. These differences often include:
- Antennae: Males tend to have larger, more feathery antennae than females
- Size: In some species, females are larger than males
- Color patterns: In certain species, the color patterns may vary between females and males
Comparison Table: Male vs. Female Giant Silk Moths
| Feature | Males | Females |
|---|---|---|
| Antennae | Larger, feathery | Smaller, thin filament or feathery depending on species |
| Size | Generally smaller | Generally larger |
| Color patterns | May vary between species | May vary between species |
When it comes to the anatomy of giant silk moth caterpillars, they often have vibrant colors and distinctive patterns to deter predators. These caterpillars may have hairy or spiky bodies, as well as various markings to help them blend into their surroundings.
Feeding and Host Plants
Preferred Leaves and Trees
Giant silk moths, members of the family Saturniidae, have specific preferences when it comes to foliage for their caterpillars. Some notable host plants and leaves that the caterpillars feed on include:
- Willow: A tree commonly found near water sources
- Apple: Fruit-bearing tree that can be cultivated in various parts of the world
- Sassafras: Native to North America, often used in traditional medicine
- Lilac: A popular flowering plant with a pleasant fragrance
- Poplar: Trees that are often used in landscaping and paper production
Caterpillar Diet
Caterpillars of the saturniid family mainly feed on a variety of leaves. They rely on these host plants throughout their larval stage. Examples of such preferred foliage include willow, apple, sassafras, lilac, and poplar trees.
Adult Diet and Mouth Parts
Interestingly, adult giant silk moths have a different diet compared to their caterpillar stage. In fact, some adult saturniids have small or absent mouthparts, making them incapable of feeding.
As a result, adult giant silk moths live for a limited period, often only a few days. Their main purpose during their short life is to mate and lay eggs. Their lack of feeding habits puts an emphasis on the significance of the caterpillar stage in obtaining the required nutrition for survival.
Reproduction and Mating Behavior
Mate Attraction
Giant silk moths typically fly at night for mating purposes. Males use their feathery antennae to detect female pheromones and locate potential mates. Females, on the other hand, have thin filament or feathery antennae depending on the species (source).
Pheromones and Mating Calls
Female moths release pheromones to attract mates. For example, male silk moths can detect a few hundred pheromone molecules among 25 quintillion molecules, making their sense of smell incredibly efficient (source).
Reproductive Success
Adult giant silk moths have small or non-existent mouthparts, which means they don’t eat. Their sole purpose as adults is to reproduce. The lipids stored as caterpillars provide nourishment during this stage (source). After mating, males and females are usually separated, and females lay eggs on host plants.
Examples of host plants:
- Oak trees
- Willow trees
- Maple trees
- Cherry trees
Overwintering
Some species of giant silk moths overwinter in their cocoons. The pupae stay protected in the cocoons during winter and emerge as adults when the temperature rises in spring or summer. This strategy helps them survive harsh winter conditions.
Predators and Defense Mechanisms
Natural Enemies
Giant silk moths, belonging to the family Saturniidae, face various predators and parasites throughout their lifecycle. Some common predators include:
- Bats: Known to prey on flying moths
- Tachinid fly: A parasitic fly that lays eggs on caterpillars
- Gypsy moth: Though not a direct predator, they compete for resources
Moth and Caterpillar Defenses
Moths and caterpillars of the Saturniidae family employ multiple defense mechanisms to protect themselves.
Moth defenses:
- Clicking sound: Some silk moths produce a clicking sound to deter bats
- Camouflage: Many species blend in with their surroundings
Caterpillar defenses:
- Parasitism prevention: Some caterpillars remove tachinid fly eggs from their bodies
- Bright colors: Warning predators of potential toxicity
Comparison Table:
| Defense Mechanism | Beneficial For | Pros | Cons |
|---|---|---|---|
| Clicking sound | Moths | Effective against bat predation | Limited to bats |
| Camouflage | Moths/Caterpillars | Reduced visibility to predators | Environment-dependent |
| Parasitism prevention | Caterpillars | Reduces tachinid fly parasitism | Time-consuming |
| Bright colors | Caterpillars | Deters predators due to toxicity | Increases visibility |
By understanding the various predators and defense mechanisms of giant silk moths, we can gain insight into their overall survival strategies.
Conservation and Human Interaction
Population Status
Giant silk moths, such as Cecropia, Promethea, Polyphemus, and Luna moths, are members of the Saturniidae family. Their population status varies depending on the region, with some areas such as the Great Plains showing declining numbers due to habitat loss.
Conservation Efforts
Conservation efforts for these moths focus on preserving their natural habitats across different regions, including Florida, Maine, and other parts of the United States. Such efforts involve:
- Monitoring populations
- Preserving host plants
- Educating the public on the importance of these species
Giant Silk Moths as Pets and Educational Tools
Giant silk moths are not commonly kept as pets, but they can be valuable educational tools. For instance, they could help teach students about:
- Insect life cycles
- Ecological interactions
- Importance of conservation
Pros of using Giant Silk Moths for education:
- Engaging visual appeal
- Unique life cycles sparking curiosity
- Sizes aiding in demonstrations
Cons of using Giant Silk Moths for education:
- Short adult lifespans
- Some species may be region-specific
Comparison Table: Luna Moth vs. Promethea Moth
| Feature | Luna Moth | Promethea Moth |
|---|---|---|
| Wingspan | 3-4.5 inches | 3-4 inches |
| Coloration | Pale green | Brownish-red |
| Habitat | Forests | Forests |
| Active Period | Nighttime | Evening |
By incorporating information on giant silk moths in science curriculum and conservation programs, we can raise awareness about the importance of these fascinating creatures and promote efforts to protect their populations.
Conclusion
Giant silk moths, belonging to the Saturniidae family, are known for their impressive size and beautiful appearance1. These moths have a relatively short adult lifespan due to their limited feeding capabilities2.
The adult moths live for only a few weeks3, spending that time mating and laying eggs. As caterpillars, they undergo several growth stages before spinning a cocoon and transitioning to adulthood.
Below is a comparison table of different Saturniidae moth species and their adult lifespan:
| Species | Adult Lifespan |
|---|---|
| Cecropia | 1-2 weeks |
| Promethea | 1-2 weeks |
| Polyphemus | 1-2 weeks |
| Luna | 1 week |
In conclusion, giant silk moths are fascinating creatures with unique features and characteristics. However, it is important to note that their adult lifespan is quite short-lived, making them a fleeting marvel in the natural world.
Footnotes
 |
 |
| Citheronia splendens | Bombardier Beetle |
 |
 |
| Cerisy’s Sphinx | Polyphemus Moth |
.
42 Comments. Leave new
Mr. Bugman…
My sons and I were delighted to see our Tulip Tree Silkmoth identified and our pictures posted for all to see!!! How fun! Thanks for your help! We are now going to be on the hunt for more bugs for you to identify for us!!! Thank you, thank you, thank you!!!
Valerie, Riley and Wesley
Hello,
I can confirm that the specimen you posted found on the shores of Pend Orielle Lake is in fact H.kasloensis. Although there are reported records of other species native to Idaho, I believe all except H.kasloensis and H.gloveri are misidentifications.
H.gloveri (which has been recently been grouped into H.columbia by M.Collins) occurs further South and East of H.kasloensis with some areas of natural ingrade populations between the 2 species in areas of S.E. Idaho. My research does not support M.Collins conclusions, I still consider H.columbia and H.gloveri to be 2 sepperate species. I am continuing with genetic studies within the Hylophora genus and am always looking for specimens (alive or dead in any stage) with good local specific data. Feel free to contact me at bugframes@msn.com,
Best regards,
Scott Smith
Thanks for this great information Scott
Haven’t checked in a couple of days, but there was recently one of these on a bush in my backyard. (Berks County, PA)
dcris,
The specimen you observed in your yard in PA would be a specimen of Hyalophora cecropia, that is the only Hyalophora species found in your state. I did recieve your e-mail with this photo (fully grown 5th instar larva) which confirms it. Awesome photo by the way! 🙂
Hi Daniel,
It’s great to read your description. Sometimes I think that most of those who write about insects either demonize them or render them through scientific discourse. Neither of those approaches can help us appreciate what’s around us.
Best,
Dave
Thanks for your support Dave
Please help me!!! I believe a rothschildia came to my house an laid eggs… now eggs are hatched (40)… many of my cat have died because of my ignorance, didn’t know about what to feed them, stressing them, molting. etc….. until now I had 10 but I think I just killed one (the oldest one) 🙁 (so sad) because I hurt her without knowing that maybe she is about to start a metamorphosis…. please… i love them!!! they were born between the 12th and 18th july… today is the 31…. what now… No one answers !!! Please let me know how to take care of them… i know nothing about butterflies !!!
I don’t have a website. Just wanted to see if and how I could submit pictures. Is it only for identifying moths?
Please use our standard submission form that can be accessed by clicking the Ask What’s That Bug? link on our site. If it crawls, it has a place on our site.
Also, is the sweetbay the tree that we call a bay tree that is similar to the magnolia?
According to BugGuide: “Caterpillars feed on Sweetbay, Magnolia virginiana.”
Me podrían ayudar por que tengo dos mariposa con estas características en mi casa y pusieron huevos y no se que hacer con ellos, si me pueden ayudar desde ya muchas gracias .
Hola Lilia,
Por favor perdona, como el español no es el mejor. Si tuvieras las polillas de seda Rothschildia ponen huevos, lo harán probablemente escotilla dentro de una semana y tendrá que proporcionar las orugas jóvenes con comida. Algunos te deja intento alimentar las orugas puede incluir: Ailanthus altissima o árbol del cielo, Ligustrum o Privet, Quercus o Robles y Syringa vulgaris o Lila común.
Hi Lilia,
Please forgive as our Spanish is not the best. If you had Rothschildia Silk Moths lay eggs, they will likely hatch within a week and you will need to provide the young caterpillars with food. Some leaves you might try feeding the caterpillars include: Ailanthus altissima or Tree of Heaven, Ligustrum or Privet, Quercus or Oak and Syringa vulgaris or Common lilac.
Fascinating caterpillar! It shows some similarity to the genus of Erinnyis, though its warning position is quite unusual for these; maybe a member of a related Macroglossinae genus. Great photos!
Nice wishes from Berlin
Thanks for your input Bostjan. It is greatly appreciated.
Trying to define my first assumption; this is clearly Erinnyis yucatana, but the green form. There is a shrub with long narrow leaves and big yellow blossoms close to the place, when I am right. Its name is Thevetia, from the Apocynaceae family, and it bears big round soft green fruits on its twigs. Am I right?
Thanks Bostjan. We will contact Elizabeth to see if she has a Thevetia growing in her yard. There is an image on Bioline International.
Many Thanks for the interesting information! I realize You have a wonderful environment with a rich nature, like a paradise; with so many different kinds of plants, the caterpillar could really be of quite some other Erinnyis species as well. What a fascinating genus of hawkmoths. And I am sure You will discover many more caterpillars in Your garden.
Happy Easter, many further interesting discoveries and nicest wishes from Berlin to all of You,
Bostjan
We found one on our front step and brought it in. It didn’t try to fly away. Later that night it laid eggs on the walls of the container. Curious as to whether they die after giving birth! What will the larva need to eat??
Adult Giant Silkmoths, including the Spicebush Silkmoth, die soon after mating. The caterpillars feed on “leaves of apple, ash, basswood, birch, cherry, lilac, maple, sassafras, sipcebush, sweetgum, tulip-tree (1); also recorded on buttonbush, magnolia, and other trees” according to BugGuide.
How does one tell the difference between a Promethea and a Tulip Tree Silkmoth? The difference between male and female is obvious, but the adult females look the same to me, even considering individual variations in color.
We would refer you to BugGuide descriptions. Here is the description of the Promethea Moth on BugGuide: “Adult: male wings blackish except for faint whitish PM line, pale tan terminal border, and pink shading around apical spot; female wings bright reddish to dark brown, usually with well-developed reniform spots [description by Charles Covell] thin meandering line near outer margin of forewing resembles side view of a set of molars in a jaw bone”, and here is the description of the Tulip Tree Silkmoth on BugGuide: “Males are brown centrally, females yellowish brown. On females the angular white spots are largest on the forewings.” We would suggest that you compare images on BugGuide. The two species do look quite similar since they are in the same genus.
Looks like or close to the one you guys identified here:
https://www.whatsthatbug.com/2014/08/05/emperor-moth-caterpillar-sierra-leone/
Thanks Cesar. You are correct. We had a long day away from the office and we just updated the posting with Bill Oehlke’s confirmation of the species. I did link to the same posting you provided.
Have a great day.
Looks like or close to the one you guys identified here:
https://www.whatsthatbug.com/2014/08/05/emperor-moth-caterpillar-sierra-leone/
I know this was posted quite a while ago, but if I may, this looks like the self-sustaining hybrid Hyalophora kasloensis (a random mixture of euryalus x gloveri genes). Though it seems a bit too far west for that variation to occur, it may be just far enough north that gloveri influence may have migrated down from Canada. Columbia just can’t travel that far west due to geographical barriers and host isolation. The foliage in the second picture is definitely fir needles (not an uncommon host for northern or high elevation euryalus). The slender, peg-like scoli on its dorsal and sides shine more true to euryalus anyway so it could also just be rare phenotypical aberation associated with that population of euryalus.
Thanks so much for this astute analysis of a very old posting.
Hi, I’m glad to read about Rothschildia again. Thanks to this site I could get to discover more of this species. In my case I found 4 caterpillars and according to Bill Oehlke (Thanks What’s That Bug?) they could be R. orizaba orizaba or R. peggyae, so I asked a close entomologist and she thinks it might be R. orizaba. Apparently it is very difficult to identify accurately, even as moths. I’m of State of Mexico and this weather will take 4-5 weeks (have your camera ready!). The species is commonly known as “Mariposa de Cuatro Espejos” in Mexico and is endangered. The common name it’s applied to multiple Rothschildia species. Here’s some pics taken by me if you’re interested: http://alfredopfoto.tumblr.com/rothschildia – Good luck! 🙂
We are so happy WTB? sparked an interest in these magnificent creatures for you.
Could it be possible that the wasp was eating or attaching it self to the moth?
That could be possible.
I agree with the identification (a male), but note that this species is previously recorded from Trinidad (although misspelt):
Quesnel, V.C. (1978) Dirphia tarquina a new moth for Trinidad. Living World, Journal of the Trinidad and Tobago Field Naturalists’ Club 1977-1978, 14.
I agree with the identification (a male), but note that this species is previously recorded from Trinidad (although misspelt):
Quesnel, V.C. (1978) Dirphia tarquina a new moth for Trinidad. Living World, Journal of the Trinidad and Tobago Field Naturalists’ Club 1977-1978, 14.
We just found one in our yard and we are in mississippi and it’s way larger and has more spikes on him. Are they dangerous
Hornworms are not dangerous to humans.
Looks like Citheronia sp.
Thanks Cesar. If you are correct, our North American representatives from the genus are much more spectacular, including the Hickory Horned Devil.
I just saw yellow jackets attacking one.
I think Bill identified this larvae (or maybe close species) on this posting: https://www.whatsthatbug.com/2015/07/05/hyalophora-caterpillar-ceanothus-silkmoth-or-columbia-silkmoth/
Thanks Cesar. The Ceanothus Silkmoth is not reported from Colorado, hence our doubt.
I also found them in Kasaragod district of kerala