How to Raise Imperial Moth Caterpillars: Your Easy Guide for Success

Raising imperial moth caterpillars can be a fascinating and educational experience. Imperial moths, known scientifically as Eacles imperialis, are one of the largest and most beautiful moth species found in the eastern United States source. With their striking appearance and size, watching these creatures develop from caterpillars into fully grown moths can be a memorable journey for both beginners and experienced enthusiasts alike.

To successfully raise imperial moth caterpillars, it’s essential to understand their life cycle and specific needs. These caterpillars, which can grow up to 5.5 inches in length source, typically feed on the foliage of host plants before transforming into stunning moths. By providing the right environment, food, and care, you can help these impressive caterpillars thrive and eventually transform into their adult moth stage.

In this article, we’ll explore the essentials of raising imperial moth caterpillars, including their preferred habitat, dietary requirements, and key aspects of their growth and development. Equip yourself with the knowledge necessary to create an optimal environment for these fascinating creatures to flourish and witness their extraordinary metamorphosis firsthand.

Understanding Imperial Moth Caterpillars

Life Cycle

Imperial moth caterpillars belong to the giant silkworm moth family. They undergo a four-stage life cycle:

1. Eggs: Females lay eggs on the foliage of host plants.
2. Larvae: Caterpillars hatch and consume the host plant leaves.
3. Pupae: Fully-grown caterpillars form into pupae and transform into adult moths.
4. Adults: They mate and lay eggs, starting the cycle again.

Imperial moth caterpillars can grow up to 5.5 inches in length and exist in various colors. For instance, they might be light or dark brown, burgundy, or green.

Host Plants

Imperial moths lay eggs on specific host plants; their caterpillars feed on these plants’ foliage. Some common host plants for these caterpillars are deciduous trees such as oak, pine, and maple. They don’t usually consume milkweed, which is the exclusive host plant for monarch butterflies.

By understanding the imperial moth caterpillar’s life cycle and its preferred host plants, you can create a suitable environment to raise these fascinating insects.

Creating an Ideal Habitat

Container Selection

When raising imperial moth caterpillars, choosing the right container is crucial. Consider these factors:

• Size: Ensure enough space for caterpillars to move around
• Ventilation: Opt for a container with a mesh or screen lid to provide air circulation

For example, a suitable container could be a large plastic container with a mesh lid.

Soil and Substrate

Imperial moth caterpillars require a suitable substrate for burrowing when they’re ready to pupate. Opt for:

• Chemical-free soil: Avoid any soil that may contain pesticides
• Vermiculite or coconut coir: Both are ideal substrate alternatives

Here’s a comparison of these substrates:

Humidity and Temperature

Maintaining proper humidity and temperature is vital for caterpillar health. Keep in mind:

• Humidity: Aim for 60-70% relative humidity
• Temperature: Maintain temperatures between 75-80°F

Use a hygrometer and a thermometer to monitor these conditions.

Adding Sticks and Leaves

Adding appropriate sticks and leaves to your container offers several benefits:

• Provides a natural environment for caterpillars
• Helps with molting and navigation

Ensure that the sticks and leaves are from their host plants, such as oak or maple trees. Replace the leaves regularly to maintain freshness.

Feeding and Nourishment

Selecting Suitable Food Plants

Imperial moth caterpillars primarily feed on leaves from a variety of plants. Some common host plants for them include:

• Oak
• Walnut
• Cherry
• Pines

Although rare, they have also been reported to feed on:

• Milkweed
• Spicebush
• Paw-paw
• Parsley
• Fennel

It’s essential to research and provide the right host plants based on caterpillar preferences in your region since diets can vary.

Dealing with Mold and Damage

Caterpillars are sensitive to their environment and can be affected by mold and damage to their food source. To reduce these risks:

• Regularly clean and replace frass: Caterpillar droppings can lead to mold growth
• Keep humidity in check: High humidity levels promote mold growth
• Remove damaged or moldy leaves immediately: Moldy leaves can affect the caterpillar’s health

When raising caterpillars, use paper towels or similar materials to line their containers for easy cleaning.

Feeding Schedule

Imperial moth caterpillars will eat leaves and plant parts based on their growth and development needs. To ensure proper nourishment:

• Provide fresh leaves daily: Caterpillars will primarily consume leaves, so offering a daily supply ensures they’re well-fed
• Gradually increase food amount: As caterpillars grow, their food consumption will increase; monitor their needs and adjust accordingly

Remember, short feeding schedules (like once every 12 hours) are better than infrequent, large portions, as this helps maintain fresh food and a healthy environment.

Caring for Caterpillars Through Each Instar

Monitoring Growth and Development

Imperial moth caterpillars go through several growth stages, known as instars. In their final instar, they can reach lengths of 75-100 mm. To ensure proper development, follow these steps:

• Observe your caterpillars daily
• Maintain a clean environment
• Provide fresh food

Keep track of their progression through instars to anticipate their needs, such as providing more food or a larger space.

Managing Population and Space

The health and wellbeing of your imperial moth caterpillar population depend on:

• Adequate space
• Proper food sources
• Good hygiene

Consider your space limitations when raising caterpillars. For example:

Keep in mind the following:

• Pets: If you have pets, make sure the caterpillars’ enclosure is secure from potential disturbances.
• Population: Large populations may require more frequent cleaning and monitoring to prevent overcrowding and stunted growth.

When raising imperial moth caterpillars, remember to focus on proper care through each instar, monitor their growth and development, and manage population size and space to ensure the wellbeing of these fascinating creatures.

Pupation and Preparation for Release

Creating a Pupation Chamber

To raise imperial moth caterpillars, it’s essential to provide a suitable pupation chamber. When these caterpillars are ready to pupate, they form a pupation cell in the soil. Prepare a one-gallon jar filled with a mixture of moistened soil and peat moss. Here’s what to include:

• One-gallon jar
• Soil and peat moss mixture

Place the caterpillar in the pupation chamber when it’s about to pupate. Make sure to bury the jar slightly underground, leaving the lid above ground for easy access.

Preventing Parasite and Pest Issues

Preventing parasite and pest issues is crucial for a successful release of the adult imperial moth. Here are some common parasites and pests to watch for:

• Flies
• Wasps

To deter these pests, cover the jar with a fine mesh or use a lid with air holes. This allows air circulation while keeping pests out. Monitor the jar regularly and look for signs of parasites such as small holes in the chrysalis.

Keep in mind that the female imperial moth is slightly larger than the male and has bright yellow wings with red-brown spots. To release your adult moth into the wild, wait until early evening when the moths are most likely to be active, and gently place them on the foliage of a suitable host plant. Observe them for a while to ensure they adapt well to their surroundings before leaving them to nature.

Other Moth and Butterfly Species to Raise

Introduction to Alternative Species

In addition to the imperial moth, several other popular moth and butterfly species can be raised at home. Some examples include:

• Monarch butterfly
• Swallowtail (Zebra swallowtail, Black swallowtail)
• Luna moth
• Cecropia moth
• Viceroy
• Red-spotted purple

Raising these species can provide a fascinating and educational experience. Let’s compare some of their features and characteristics:

These species can be a great addition to an insect collection or simply raised for enjoyment and observation. Keep in mind that different species may have different requirements when it comes to raising them, such as suitable host plants, appropriate habitats, and dietary needs.

For instance, while the Monarch butterfly relies exclusively on milkweed as its host plant, other options can be explored with other species. Swallowtails, for example, use different host plants depending on their specific variety, whereas Luna moths are dependent on plants like sweetgum and hickory.

By understanding the specific needs of each species, you can create a suitable environment for them to grow and flourish. Whether you’re raising them for educational purposes, as a hobby, or for butterfly and moth conservation, these species offer diversity and a unique experience for enthusiasts of all levels.

Helpful Tips and Tricks

Raising imperial moth caterpillars can be a fascinating and rewarding experience. Here are some helpful tips and tricks to ensure their healthy development.

• Choose host plants wisely.
  Caterpillars feed on the foliage of host plants, so it’s crucial to pick the right ones. Imperial moth caterpillars are known to grow on various trees, including maple, oak, and walnut¹.

• Create a suitable habitat.
  Your caterpillars need a comfortable environment to thrive. Provide them with:

  • Fresh leaves for consumption
  • Sticks for support
  • A container with a lid and air vents

• Monitor their growth.
  You’ll be amazed to watch these caterpillars grow, sometimes reaching up to 5.5 inches in length¹. Keep an eye on them to ensure they’re healthy and well-fed.

• Handle with care.
  Ensure you handle the caterpillars gently when necessary. Avoid touching them directly with your hands; use a paintbrush or a soft plant material instead.

Imperial moth caterpillars undergo several stages of development. Here’s a comparison table to help you recognize each stage:

Remember to:

• Provide fresh leaves at each stage of the caterpillar’s life.
• Clean the container regularly to keep it free from waste.

By following these simple tips, you’ll be well on your way to raising healthy and happy imperial moth caterpillars!

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 – Imperial Moth Caterpillar

Big Red Caterpillar
Can you identify this one? Found on Isle of Hope, Georgia.
Matthew A. Bryan

Hi Matthew,
The Imperial Moth Caterpillar is a highbly variable caterpillar in coloration. We have never seen one this red. Also, the spined dorsal tubercles on second and third thoracic segment on your specimen are a little different than we normally see. A lateral view would have been nice to see on your specimen.

Letter 2 – Imperial Moth Caterpillar

What an awesome, detailed photo you have sent to us. Can you confirm this as an Imperial Moth caterpillar? From my reading, it should pupate in the ground or under leaf cover – I am watching it dig in under leaf litter. Can I recover the chrysalis when it’s hard and keep it where I can watch it hatch out? Does it need special conditions to thrive? Love the site – spend ‘way too many hours looking at bugs!
Beth R.
Wimberley, TX

Hi Beth,
What an awesome, detailed photo you have sent to us. You are absolutely correct. This is an Imperial Moth Caterpillar. Probably the best way to keep the pupa for observation is to capture the caterpillar and keep it in a 5 gallon aquarium with several inches of loose, damp earth. The caterpillar will pupate when it is ready. Do not let the earth get too dry, but it is more important that it not get too wet. Mist it about once or twice a week with water. Keep a screen cover over the aquarium so there is air circulation. Keep the aquarium where it won’t freeze since it is not as well protected as if the caterpillar had buried itself in the ground. Do not keep the aquarium indoors as it will be too warm. Good luck.

Letter 3 – Imperial Moth Caterpillar

Caterpillar???
Any idea what kind of caterpillar this is? I found it on the front porch of my house in Austin, TX. Thanks!
John

Hi John,
After identifying three Imperial Moth Caterpillars today for readers from Texas, we thought we should post the best of the photographs, and that is yours.

Letter 4 – Imperial Moth Caterpillar

question on a caterpillar…
Hi there,
Love the site. Can you help me identify this one? It was in our front yard about a month ago. It measures 4-5 inches long. Biggest caterpillar I’ve encountered here. We had a very wet summer and have found many interesting things this fall including a Texas Brown tarantula (which we have as a pet now!). Thanks!
Penley
Austin Texas

Hi Penley,
This is an Imperial Moth Caterpillar. There are several color variations in addition to the orange coloration in your photo. They might also be green, blue-green, golden or brown. They feed on a on the leaves of variety of deciduous and coniferous trees. Yellow and purple adults do not feed and live but a few days.

Letter 5 – Imperial Moth Caterpillar

large caterpillar found in our yard near Charleston SC
Hello,
attached please find a photo of the largest caterpillar my husband and I have ever seen. Any ideas what it is and what we should feed it or where we should put it to feed itself? thanks,
Kate Hammond
Summerville, SC

Hi Kate,
This magnificent specimen is an Imperial Moth Caterpillar, Eacles imperialis. We have numerous images of the stages of metamorphosis of this beautiful moth. The caterpillar looks to be about ready to pupate, judging by its color, though this is a highly variable caterpillar with regards to coloration. It will pupate underground in loose soil. It is not interested in eating at this point. The caterpillars are often discovered searching for a good place to dig into the ground after leaving the trees upon which they have been feeding.

Letter 6 – Imperial Moth Caterpillar

What’s my bug (caterpillar)
Hello you intelligent bug lovers!
On behalf of Yulee Elementary School in Yulee, FL, thanks for making this informative and colorful site. One of my co-workers has asked me to identify this species. She has it co-inhabiting a jar w/ oleander larvae. I have looked at all the submitted photos but still can’t decide what this is. Can you help? If you respond you’ll be informing almost 900 3rd-5th graders and their teachers. You may inspire a new generation of bug lovers. ps any hints on how we can feed it would also be appreciated.
Mary Austin-Harris,
Yulee, Florida

Hi Mary,
There was no way we were going to pass up the opportunity to educate almost 900 elementary school students and their teachers. This is an Imperial Moth Caterpillar, Eacles imperialis. According to BugGuide, they: “feed on leaves of Bald Cypress, basswood, birch, cedar, elm, hickory, Honeylocust, maple, oak, pine, Sassafras (Sassafras albidum ), Sweetgum (Liquidambar styraciflua), sycamore, walnut. “

Letter 7 – Imperial Moth Caterpillar

caterpillar
Hi I found this monster in my koi pond in Iowa. I thought he was dead, but I laid him gently out to dry. He’s still alive and crawling around. Can you tell me what it is? I have a couple of other pictures of it.
Donna Hansford

Hi Donna,
It is the time of the year for caterpillars that burrow in the ground to pupate to leave their trees and shrubs in search of a place to metamorphose. These large caterpillars have gone unnoticed as they were feeding, but many of or readers encounter them once they reach ground level. Your caterpillar is an Imperial Moth Caterpillar.

Letter 8 – Imperial Moth Caterpillar

Huge Green Caterpillar
Location: Fort Myers Florida
December 6, 2011 4:14 pm
Hi, I was pruning our coco plums (Chrysobalanus icaco) today Dec six when I found this caterpillar chowing down. He is twice as long as my thumb and as wide. I live in Fort Myers FL. I searched your site to find a picture & info. about this caterpillar, but did not find any. Maybe this is a different species! Thanks in advance for your help!
Signature: Carol Schumann

Dear Carol,
These are positively gorgeous photos of an Imperial Moth Caterpillar, Eacles imperialis.  Thanks for also providing the name of the food plant, the coco plum.  A recent posting of this species from September shows a brown coloration that could be either a color variation, or more likely, the darkening of the pre-pupal caterpillar that usually leaves its food plant to find an appropriate place to dig into the soil to undergo metamorphosis.

This is so cool!  Thank you for the ID!  I had so much fun out there watching him eat and taking his picture! 🙂

Letter 9 – Imperial Moth Caterpillar

Subject: what’s this bug?
Location: Northern Indiana
October 28, 2012 2:05 am
Hi & thanks for the great information you share.
I’ve looked up many wonderful creatures on your site and I finally have one to submit 🙂
This cool creature fell from a maple tree onto our deck in mid-August. It’s about the most exotic thing I’ve seen in Indiana so what can you tell me about it?
Again, thanks for the info. you share with the world.
Signature: ae

Hi ae,
Thank you for your complimentary email.  This very distinctive caterpillar is an Imperial Moth Caterpillar, one of the Giant Silkmoths in the family Saturniidae.

Letter 10 – Imperial Moth Caterpillar

Subject: Caterpillar identification
Location: Southern indiana
September 22, 2013 11:55 am
This was found in our yard in southern indiana by our kids and nephews and I wondered if you would help me identify it! It is about middle figure length and width. Please see attached and thanks!
Signature: Trevis

Hi Trevis,
Autumn is the time that caterpillars have attained their maximum growth and they leave the trees and plants that they have been feeding upon to find a place to pupate, making them much more visible.  This is the caterpillar of an Imperial Moth, Eacles imperialis.  Adult Imperial Moths are yellow and purple in coloration.

Letter 11 – Imperial Moth Caterpillar

Subject: Can you identify?
Location: Orrstown, PA
September 22, 2014 6:28 am
I was wondering if you could tell me what kind of caterpillar this is? Found it eating one of my pine trees. Can you help me? I am worried about my trees. Please and thank you.
Signature: Lori

Dear Lori,
This is the caterpillar of an Imperial Moth, and recent taxonomic changes have resulted in the recognition of a subspecies, the Pine Imperial Moth, Eacles imperialis pini, with a caterpillar that feeds exclusively on conifers.  According to BugGuide:  “larvae feed exclusively on conifers, mainly White Pine and Red Pine; also recorded on Jack Pine, Scotch Pine, and White Spruce” and “uncommon and local in Ontario; rare and local in Quebec and elsewhere within its range.”  Unless they are so plentiful as to defoliate plants, caterpillars are generally not much of a problem when they feed on trees.  The few leaves, or in your case the few needles, that are lost do not have a negative impact on the health of the trees.

Thank you very much. I feel much better.

Letter 12 – Imperial Moth Caterpillar

Subject: Imperial Moth?
Location: South Central Pa
August 24, 2015 5:03 pm
My husband found this on his maple tree.
8.24.15
We’ve never seen a caterpillar this big.
Our neighbor said it’s a monarch but your page is looking like imperial moth
Signature: Amy Jo

Dear Amy Jo,
Your identification of this magnificent Imperial Moth Caterpillar is correct, and judging by its size, it will soon spin its cocoon.

Thank you.     Its the prettiest caterpillar I’ve ever seen.  I’m checking our trees for more!  Lol

Letter 13 – Imperial Moth Caterpillar

Subject: Never saw a caterpillar this large before!
Location: Front yard on the grass
September 11, 2015 9:16 pm
It’s huge! What species is this? Are the poisonous? Very cool little dude!
Signature: -Ashley

Dear Ashley,
This is an Imperial Moth Caterpillar.  Normally, our “location” field is used to identify a city, state, country or continent where the critter was sighted.  Interestingly, there is not a blade of grass in your image, despite the location being listed as “Front yard on the grass.”

Letter 14 – Imperial Moth Caterpillar

Subject: Unidentifiable worm/ caterpillar
Location: High Falls NC.
October 2, 2015 5:44 pm
Help Bugman,
I live in the Piedmont region of North Carolina in the small community of High Falls. I live in a wooded area, no close neighbors, near Deep River. I found this worm/ caterpillar or whatever it may be crawling in my driveway. I can’t find anyone who has ever seen anything like it can you please try to identify?
Signature: Anna Moore

Dear Anna,
This is an Imperial Moth Caterpillar, and its size and color indicate it has left the tree upon which it was feeding and it is searching for a suitable place to pupate.  Adult Imperial Moths are quite beautiful.

Letter 15 – Imperial Moth Caterpillar

Subject: Big bug
Location: Gainesville, Florida
August 21, 2016 11:18 am
This bug moved like a caterpillar, it moved quick.
It was 5″ long and very fat. I did not kill it.
Signature: Curious

Dear Curious,
This Imperial Moth Caterpillar is most likely looking for a place to dig beneath the surface to pupate.

Letter 16 – Imperial Moth Caterpillar and adult Moth

Subject: Fat Weird Caterpillar
Location: Maryland
September 11, 2016 5:27 pm
Hey!
Apparently this fell on my cousin out of a tree (no worries she put it back and it was NOT harmed in anyway) and I’m not quite sure what it is, perhaps you may know? I’ve never seen one like it around here, but maybe it’s common? Let me know when you get the chance and thank you for all you do!
Signature: Rochelle

Dear Rochelle,
This is the caterpillar of an Imperial Moth, and its size and color indicate that it is getting ready to transform into a pupa, which it does underground.  When that time approaches, the normally green caterpillar changes color and loses interest in eating leaves.  It falls or descends to the ground and find a suitable place to dig.  While your cousin had good intentions to place it back in the tree, this individual most likely immediately set upon getting back on the ground.  Because of your cousins kind intentions, we are tagging this posting with the Bug Humanitarian Award.

Hello Daniel!
Thank you so much for getting back to me, you literally made my day! I work at a bagel shop where we have a dry erase board where we put fun facts and trivia for people to look at while they eat and I’m going to make the caterpillar of the Imperial Moth the Animal of the day! Ill send you a picture when it’s done! Thank you again, you and your team are truly great people and its awesome to know that there are other bug friendly enthusiasts out there! Have a wonderful evening,
Rochelle

In honor of you and your peeps and for the magnificent creature that is the Imperial moth. I’m actually a decent artist but its hard to draw with dry erase markers.. Also I just saved an Imperial Moth from the hallway of my apartment a few weeks ago and I’m pretty mad at myself for not knowing what the pre-pupa form looked like… Either way, thank you again for the response and keep up the good work!
Rochelle

Wow, thanks for the awesome update.

No problem! I’m honestly just thrilled that you took the time to write back and now that I know you have a book for sale… 😀

Letter 17 – Imperial Moth Caterpillar

Subject:  Caterpillar
Geographic location of the bug:  Northern Ontario
Date: 08/09/2018
Time: 08:10 AM EDT
Your letter to the bugman:  Have searched a bit but not confident about what type this is.
Possibly an imperial?
How you want your letter signed:  Cindy

Dear Cindy,
This is indeed an Imperial Moth Caterpillar, and its darker coloration indicates it is getting ready to pupate.  Caterpillars will frequently change color and leave the host plant when it is time to pupate, so we are guessing it was found on the ground as Imperial Moth Caterpillars pupate underground.

Letter 18 – Imperial Moth Caterpillar

Subject:  What is this
Geographic location of the bug:  Southwest Florida
Date: 08/27/2021
Time: 07:07 PM EDT
Your letter to the bugman:  Found this crawling around on rocks today in my landscaping
How you want your letter signed:  Bugman

To Whom it may Concern,
You are not the Bugman.  You have requested information from the Bugman.  This is a prepupal Imperial Moth Caterpillar which has finished feeding, left the tree upon which it was feeding, and it is now looking for a place to dig so it can pupate underground.  The adult Imperial Moth is a gorgeous creature.

Lol! I am certainly not the bugman! I thought that space was for how I wanted the letter to me signed; I was very concerned! Thanks for the information!
Crysta aka NOT the bugman

Thanks Crysta.

Letter 19 – Imperial Moth Caterpillar

Subject:  Caterpillars id
Geographic location of the bug:  Midwest usa
Date: 10/02/2021
Time: 05:31 PM EDT
Your letter to the bugman:  I’ve never seen a caterpillar this big in my life. Is it a danger to my clothing, garden, cats or dogs that may get hold of it? What kind is it?
How you want your letter signed:  stephanie

Dear Stephanie,
The midwest is a big place.  More location specificity is always desirable.  This is an Imperial Moth Caterpillar and it will not harm your clothing or your cats or dogs.  Imperial Moth caterpillars are not too particular about the leaves they feed upon and according to BugGuide:  “Larvae feed on leaves of Bald Cypress, basswood, birch, cedar, elm, hickory, Honeylocust, maple, oak, pine, Sassafras (Sassafras albidum), Sweetgum (Liquidambar styraciflua), sycamore, walnut.”  They do not feed enough to cause a tree damage unless it is a very young tree.

Letter 20 – Imperial Moth Caterpillar from Canada

Subject: Large Green Caterpillar
Location: Gatineau, Qc (just north of Ottawa)
August 21, 2015 6:35 pm
Hello. I observed and photographed this amazing specimen on August 7th at our cottage. It was 4-5 inches long. I searched and I searched the web to try to ID what type of moth this is, but without any success (but I did learned about many other beautiful large green caterpillars!!). I’ll be able to sleep better and smarter once I know what this is 🙂
Signature: Daniel C.

Dear Daniel,
This is an Imperial Moth Caterpillar, and you are correct that it will eventually metamorphose into a large and beautiful Imperial Moth.

Letter 21 – Imperial Moth Caterpillar

Subject: Caterpillar identificAtion
Location: Central New Jersey
September 15, 2013 9:32 am
Found this guy 9/15/13 in central New Jersey in my yard. Roughly 4” long and as round as a nickel.
Signature: Lisa

Dear Lisa,
This is the caterpillar of an Imperial Moth, and it has likely left the tree upon which it has been feeding so that it can find a suitable site for pupation.