Silkworm Moth: All You Need to Know in a Nutshell

Silkworm moths are fascinating creatures that play an essential role in producing silk – a material valued worldwide for its beauty and durability. These moths, belonging to the family Saturniidae, are not only unique for their silk-producing capabilities but are also known for their eye-catching appearance. With an array of vibrant colors, intriguing patterns, and, in some cases, impressively large wingspans, silkworm moths are definitely worth learning about.

Did you know that female silkworm moths have either thin filament or feathery antennae, depending on the species? These insects also have a short lifespan; as adults, they live for just a few weeks without feeding. Their mouthparts are small or sometimes absent altogether. With around 16 species in Missouri alone, there’s a lot to discover about these enchanting moths.

Diving into the world of silkworm moths, you’ll find captivating details about their life cycle, breeding habits, and the silk production process. From their beginnings as tiny eggs to their transformation into stunning adult moths, it’s truly remarkable how these insects contribute significantly to the textile industry. So, come along and explore the intriguing life of silkworm moths – you might be amazed by what you find.

What is a Silkworm Moth?

A silkworm moth is a fascinating creature belonging to the family Saturniidae, which includes some of the largest and most colorful moths in the world, known as giant silkworm and royal moths. They possess stout, hairy bodies and distinctive feathery antennae.

Now, let’s learn more about the silkworm moth’s life stages. These moths undergo a captivating transformation process, which includes four key stages: egg, larva, pupa, and adult. During the larval stage, the silkworm moth is a small caterpillar, which is crucial for the silk production industry as it spins a cocoon made of silk fiber.

Silkworm moths are famous for their contribution to the production of natural silk. The most well-known silkworm species is Bombyx mori, commonly known as the domestic silkworm. It has been bred for thousands of years to optimize silk production.

Here are the main characteristics of silkworm moths:

  • Medium to large size moths
  • Stout, hairy bodies
  • Feathery antennae
  • Adults do not feed

Please remember that the silkworm moth’s adult stage is brief because their mouthparts are absent or too small to eat. As a result, their lifespan comprises just a few weeks without feeding.

In summary, silkworm moths are fascinating insects with astonishing life cycles and aesthetic features. They are especially cherished and valued for their role in producing natural silk.

Silkworm Moth Life Cycle

Eggs and Hatchling Stage

In the beginning, the life cycle of a silkworm moth starts with eggs. Female moths lay their eggs, usually on mulberry leaves, which will later become the hatchlings’ primary food source. Temperature plays a crucial role in the hatching process, generally taking around 10-14 days in a warm environment.

Larva and Caterpillar Stage

Once the eggs hatch, they turn into tiny larvae called caterpillars. At this stage:

  • Silkworms primarily feed on mulberry leaves.
  • Their growth is rapid, often going through four distinct instars (stages) before pupation.
  • They can change color, typically from yellowish-white to grayish-brown.

Pupa and Cocoon Stage

As the caterpillars mature, they enter the pupa stage. During this stage:

  • Silkworms spin their cocoon, a protective shell made of silk.
  • Pupation occurs, where the larva transforms into an adult moth.
  • This stage can last from 14 to 20 days, depending on the environment and species.
B. mori B. mandarina
Domesticated Wild
More reliant on human intervention More independent in nature

Adult Stage

Finally, the adult silkworm moth emerges from the cocoon. In this stage:

  • Adult moths have a wingspan of 40-50mm, with white to light brown coloration.
  • They release pheromones to attract their mates.
  • Male moths tend to have larger, more feathery antennae to detect female pheromones.
  • After mating, the female moths lay eggs, and the life cycle continues.

By understanding the life cycle of silkworm moths, you can appreciate their unique transformation from eggs to adults and even utilize their silk-producing capabilities. Note that the domesticated Bombyx mori relies more on human intervention, whereas the wild B. mandarina can survive independently.

Silkworm Moth’s Diet

Preferred Foods

Silkworm moths, in their caterpillar or larval stage, have a specific preference when it comes to their diet. They mainly feed on mulberry leaves. In fact, these leaves are crucial for the silkworms’ growth and development. For example, the most common species, Bombyx mori, relies heavily on mulberry leaves for their nutritional requirements. However, if you’re raising silkworms, you may also use silkworm chow as an alternative. This chow is a specially formulated diet that satisfies their nutritional needs.

Feeding Times

Caterpillars have quite high feeding frequency. They eat multiple times daily, usually around the clock. During their entire larval stage, silkworms undergo major growth and development. Consequently, they rely on constant feeding to fuel their metamorphosis process. Keep in mind that the availability of food directly affects their overall health as well as the quality of the silk they produce. So, it’s essential to provide fresh mulberry leaves or silkworm chow on a regular basis.

In summary, as a silkworm caterpillar, having access to mulberry leaves or silkworm chow for nourishment throughout the larval stage is a vital aspect of their diet. Feeding them multiple times a day ensures they grow healthily and generate high-quality silk.

Silk Production

Process of Making Silk

Silkworms, specifically the Bombyx mori, are at the core of silk production. The life cycle of a silkworm begins as eggs that hatch into caterpillars, which then consume mulberry leaves or specialized silkworm chow to facilitate growth. As these caterpillars mature, they turn into pupae and spin cocoons made of silk protein fibers.

Typically, a cocoon is boiled to soften the silk fibers to extract the raw silk. This process also kills the pupae inside. The long, continuous filaments are then collected, spun, and used to create luxurious fabrics. The byproducts left from the extraction of the silk are sometimes used to feed fish.

Industry and Economic Impact

The silk industry has had a considerable global impact for centuries, serving as a major trade hub. It has provided millions of jobs and livelihood opportunities to millions of people, especially farmers in countries like China and India. Some key aspects of the industry are:

  • China maintains its status as the world’s largest silk producer
  • Rapid advancements in sericulture have bolstered the industry
  • The demand for silk remains strong due to its lustrous properties and strength

However, the industry faces numerous challenges, including competition from synthetic fibers, fluctuating market prices, and rising production costs.

Animal Welfare Concerns

Although silk production contributes to economic growth and supports many farmers, there are significant animal welfare concerns surrounding the process. Specifically, the practice of boiling cocoons with the pupae still inside has drawn scrutiny from animal rights advocates. Some ethical silk production methods have been developed to respond to these concerns, such as:

  • Peace silk or Ahimsa silk: Allows the moth to emerge from the cocoon before boiling, creating a less lustrous but more ethically-produced silk
  • Eri silk: Extracted from the cocoons of Samia cynthia ricini, which have a more open structure that allows the moth to escape before boiling

As the silk industry evolves, innovations in ethical silk production methods continue to emerge, offering consumers more conscious choices.

Silkworm Moths as Pets

Choosing a Silkworm Moth

Selecting a silkworm moth for a pet is an exciting process. It begins with choosing the right species of silkworm moth. The most common and widely available is the Bombyx mori. These are known for their silk production, and their caterpillars are typically cared for as pets. You can obtain silkworms in different stages, such as eggs, larvae, or even adults. Remember to choose healthy silkworms with no visible injuries or signs of sickness.

How to Care for Silkworm Moths

Caring for your silkworm moths involves appropriately preparing their environment and ensuring they have the right nutrition. Provide them with an enclosure that has:

  • Adequate ventilation
  • A secure lid to prevent escapes
  • Room for them to grow and move around

You can use a plastic container with small air holes as a simple and cost-effective solution.

Temperature and humidity are crucial to your silkworm’s health. Maintain a temperature between 68°F to 78°F (20°C to 25°C) and a humidity level of around 50%.

Feeding

Proper nutrition plays an essential role in the care for silkworm moths. For their primary diet, provide them with fresh mulberry leaves or specialized silkworm chow. You can find silkworm chow online or at specialized pet shops. A well-rounded diet will ensure proper growth and help prevent health issues.

Comparison Table: Bombyx mori vs. Other Silkworm Moths

Feature Bombyx mori Other Silkworm Moths
Size Smaller Larger
Color White Varies
Care Easy Moderate
Diet Mulberry leaves or silkworm chow May require specific plant species

Caring for silkworm moths as pets is a unique and rewarding experience. By taking the time to choose the right species, maintaining their environment, and providing the proper diet, you’ll be able to enjoy watching your little silkworms grow into beautiful moths.

Diseases and Predators

Common Diseases

Silkworms (Bombyx mori) and their close relative, B. mandarina, are members of the family Bombycidae. These caterpillars are highly vulnerable to various diseases and infections. The most common diseases are:

  • Bacterial infections: Silkworms can contract bacterial infections that can result in death. They usually occur in dark and damp environments where bacteria thrive. It’s important to maintain a clean and dry habitat to prevent these infections. Bacterial diseases like Flacherie, caused by consuming contaminated mulberry leaves, are particularly harmful to the larvae.

  • Fungal infections: Fungi can also infect silkworms and cause diseases such as Sporotrichosis, also known as “rose gardener’s disease”. This fungal infection is caused by a fungus called Sporothrix that lives in soil and on plant matter.

By regulating their environment and using pesticides when necessary, you can significantly reduce the risk of disease among silkworms.

Common Predators

Silkworms, particularly in their caterpillar and larvae stages, are vulnerable to predators, many of which are attracted by their size and nutritional value. Some common predators include:

  • Ants: Ants are attracted to silkworms as a food source, and large colonies can quickly devastate a silkworm population.

  • Reptiles: Many reptiles, like lizards and skinks, will eat silkworm caterpillars if given the chance.

It is essential to protect your silkworm colony from these predators by creating a safe and secure habitat for their development.

History and Origin

History of Silkworm Moths

Silkworm moths have a rich history and are closely interwoven with the development of human civilizations, especially in the East. Originating from China, the art of sericulture, or silk production, dates back thousands of years. Through the Silk Road, silkworm moths played a significant role in connecting ancient Asia and Europe, shaping the course of history for many countries.

The most well-known domesticated silkworm species is Bombyx mori, which came from its wild ancestor, the B. mandarina. The domesticated silkworm has become a crucial part of the silk industry worldwide.

Domestication and Breeding

The process of silkworm domestication began with early farmers and silk producers selecting and breeding silkworms with desirable traits. Throughout history, numerous breeds of silkworms have been developed to improve silk production. These breeds cater to different requirements, such as diverse climates or silk qualities.

In recent times, the field of biotechnology has led to the creation of genetically modified silkworms. By altering their genetic makeup, scientists can enhance specific silk properties or introduce new ones, opening up fresh avenues for the silk industry.

To sum up, the silkworm moth has a long history, and its domestication has been crucial for silk production. Nowadays, breeding techniques and genetic modifications continue to shape the silk industry, ensuring its ongoing significance in global trade and culture.

Interesting Silkworm Moth Facts

Silkworm moths have intriguing characteristics that you may find fascinating. They come in various colors, sizes, and exhibit unique behaviors. In this section, we’ll explore some remarkable facts about these captivating creatures.

When it comes to size, the wingspan of silkworm moths can vary. For example, the Giant Silkworm and Royal Moths can have a wingspan of up to 5 inches. Their size definitely contributes to their striking appearance.

You’ll notice that many silkworm moths have distinctive markings that help them blend into their surroundings. Common patterns are stripes and spots on their wings. These patterns serve a purpose, as they aid in camouflage and deter predators.

The process of metamorphosis is truly fascinating in silkworm moths. During this transformation, they progress from eggs to larvae (caterpillars) to pupae and finally become adult moths. The pupae stage is particularly interesting, as it marks a crucial step in the development of these insects.

Silkworm moths are famous for their role in silk production, but did you know they also communicate through chemicals called pheromones? One such pheromone is bombykol. Female moths release bombykol from glands in their abdomen, attracting males to facilitate reproduction.

Genetics plays an essential role in the moths’ features and behaviors. Some genes contribute to their striking colors and patterns. Others influence the moths’ innate ability to produce and respond to pheromones such as bombykol.

To sum up some key silkworm moth facts:

  • Wingspans can reach up to 5 inches.
  • They exhibit various colors and patterns, such as stripes and spots.
  • Metamorphosis is a remarkable process, going from egg to larva to pupa to adult moth.
  • Pheromones like bombykol are critical for communication and reproduction.
  • Genetics plays an essential role in these moths’ features and behaviors.

So there you have it! Some interesting facts about silkworm moths to further your knowledge and appreciation of these magnificent creatures.

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 – Beautiful Caterpillar from Brazil may be Arsenura angulatus

 

Subject: Unknown Caterpillar
Location: Juiz de Fora-MG – BRAZIL
March 6, 2016 7:43 am
Hello Mr. Bugman, How are you? I´m fine. Today I´m sending this beautiful caterpillar that I found feeding of Heliocarpus appendiculatus. I don’t know if it is Arsenura orbignyana, but I´m accompanying the cycle finish. What is your opinion?
Thanks so much. Greetings from Brazil! Marcelo Brito
Signature: Marcelo Brito de Avellar

Giant Silkworm: Arsenura species we believe
Giant Silkworm: Arsenura angulatus

Dear Marcelo,
These are gorgeous images of a positively gorgeous caterpillar that is probably from the family Saturniidae.  Upon doing some research on the genus
Arsenura, images available online look quite similar, including these images of Arsenura drucei on Caterpillar Eyespots.  The closest match we could find is of Arsenura angulatus pictured on FlickR.  An even closer match is a poor quality image of Arsenura xanthopus pictured on the World’s Largest Saturniidae site.  We will contact Bill Oehlke to get his opinion, and we suspect he may request permission to post your excellent images that document at least two instars.  The earlier instar possesses the caudal horn, which is shed during molting, leaving a caudal bump, a phenomenon that is common in some Hornworms from the family Sphingidae.

Giant Silkworm: Arsenura species we believe
Giant Silkworm: Arsenura angulatus

Bill Oehlke Responds
Daniel,
I am pretty sure they are Arsenura xanthopus. I do not think there is such a species as Arsenura ungulates. I think ungulates is a term for hooved animals that travel in herds, and probably the term ungulates was used in reference to prominent false legs or that these often travel and feed in large groups. Thanks.  I realize it is extra work for you, but having dates and food plant are often very useful. Sometimes the local residents know the foodplant, and that is very useful information to anyone who wants to try to rear this species. Sometimes it can also help with ids.
Thanks for thinking of me
Bill

Thanks Bill,
We suspect our email program autocorrected “angulatus” into “ungulates” and the food plant was listed as
Heliocarpus appendiculatus.

Daniel,
Yes, I think they are of Arsenura angulatus, probably 4rth and 5th instars. Thanks for the fodplant. I figured out there must have been a mistake with the spelling after I hit the send button.
Bill

Giant Silkworm: Arsenura species we believe
Giant Silkworm: Arsenura angulatus

Letter 2 – Buckmoth Caterpillars

 

What are these!?
Location: Branson, MO
October 24, 2011 2:09 am
Hey, was on a hike with the fam in Branson, MO and I found these caterpillar worm looking things all over this leaf. Here’s a couple photos for ya. Hopefully you can identify them for me.
Signature: Carson

Buckmoth Caterpillars

Hi Carson,
These sure look to us like Buckmoth Caterpillars, possibly
Hemileuca maia based on this BugGuidephoto.  Your email did not indicate if this is a recent sighting.  We suspect it was earlier in the season.  Please clarify.  Was the tree an oak?  

Buckmoth Caterpillars

 

Letter 3 – Caterpillar Aggregation from Honduras: Arsenura armida

 

Aggregating Larvae
August 30, 2009
Don’t have much info other than that these are rather large larvae on a tree in Honduras. Photo taken by a friend of a friend.
Scott
Honduras

Arsenura armidas aggregation
Arsenura armida aggregation

Dear Scott,
Over the years, we received similar images four times before we finally identified the Caterpillars as Arsenura armida, a Neotropical Silkmoth that ranges from Mexico to Brazil.  Here is a website with information on the caterpillars.  The God of Insects website has an image of the adult moth.

Letter 4 – Caterpillar Aggregation from Mexico

 

Subject: Colorful Caterpillars
Location: Quintana Roo, Mexico
October 25, 2013 6:20 am
We saw this cluster of colorful caterpillars hanging on a tree at Coba Mayan Historical Park. Our guide told us they would become ”beautiful butterflies in just a few days.” I’m wondering what they are?
Signature: MS

Caterpillar Aggregation:  Arsenura armida
Caterpillar Aggregation: Arsenura armida

Dear MS,
We have several images in our archives of similar caterpillar aggregations and we have identified them as the caterpillar of a Silkmoth
Arsenura armida, not a butterfly.  Here is an image from Project Noah and a wonderful page with additional information.

Letter 5 – Buck Moth Caterpillar

 

Do you know what this caterpillar is?
Location: San Diego, CA
May 27, 2011 12:31 pm
We found this caterpillar in San Diego CA at Mission Trails Regional Park on a willow tree. We can not figure out what it is. Can you help. Thanks.
Signature: D in SD

What's That Nymphalid Caterpillar???

Dear D in SD,
The basic coloration and morphology of your caterpillar and its presence on Willow immediately suggested a Mourning Cloak, known as a Camberwell Beauty across the pond, however, no photos on BugGuide look like this.  Mourning Cloak Caterpillars are black spiny creatures (DO NOT TOUCH) and they have 8 rows of orange red dots along the back.  Your caterpillar appears to have 9 double rows of orange spines and its variegated pattern is beautiful.  We really wish your lateral view was not so blurry.  We suspect your caterpillar, whatever it might be, may irritate human skin if in contact with the spines.  We did additional research and the Green Comma,
Polygonia faunus, also feeds on “willows and birches and others” according to Jeffrey Glassberg’s book Butterflies through Binoculars The West.  The photos we found online look even more drastically different than the Mourning Cloak Caterpillar photos posted to BugGuide.  Could it be Chlosyne harrisii Harris’s Checkerspot, which we found on the Moth Photographers Group by scrolling down the page.  What does Chlosyne harrisii eat?  NOPE according to BugGuide, it ranges elsewhere.  Here is the Butterflies and Moths of North America website page on the Green Comma.

Brush Footed Butterfly Caterpillar on Willow

Alas, our search has turned up nothing conclusive.  We strongly believe that the key to a correct identification here is the presence on Willow.
P.S.  NEW THOUGHT:  Might it be a moth caterpillar like a Buck Moth?

Correction courtesy of Keith Wolfe
“D” and Daniel, this is a Hemileuca (Saturniidae) larva.  These nymphalid look-alikes confused me, too, when I first started studying young butterflies.
Best wishes,
Keith

Hi Keith,
Funny, Buck Moths did cross my mind when I was researching this caterpillar.

Hi there.  Thanks for looking into this for me.  After looking Butterflies and Moths of N.A. I do think it is a Nevada Buckmoth.
I really appreciate the time you took to check it out.
D in SD

Bill Oehlke supplies a response
Daniel,
It is definitely Hemileuca nevadensis for first one
and for second one as well.
Bill Oehlke

Authors

    by
  • 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.

  • 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.

16 thoughts on “Silkworm Moth: All You Need to Know in a Nutshell”

  1. A.armida: very edible!
    I tried this species in 4/10 at an international conference on entomophagy; one of the presenters had brought them from Mexico, and said that they’re farmed in the southern part of the country. Fascinating.
    They were also exceedingly tasty, if rather unusual. They were fried or rather sauteed, and tasted like a cross between bacon and jerky. Quite yummy, actually.

    Dave
    http://www.smallstockfoods.com

    Reply
  2. Hi! I have to say that I have found the same caterpillars in the same location, and I’ve been doing some extensive research and while I agree that it is a Hemileuca I do not think it is a Nevada Buck Moth as from all the pictures I can find those they have a different coloration. Their skin appears distinctly speckled in appearance with some prominent striping on the sides. These San Diego Hemileuca have a much more yellow color as well as a more mottled appearance to their skin and not the distinct speckling seen in H. nevadensis, H. electra, or H. eglanterina that are said to be the only Hemileuca found in San Diego county. It is my understanding that Hemileuca are prone to pockets of specific population variance. I think we may have one of those small specific area population variances in this case, and that this sp. may be a local sub sp. of Hemileuca (Saturniidae). But we will see. I have brought 5 of them home and am feeding them fresh salix every day. I have posted photos of them on Bug Guide and as they mature I will continue to update those. http://bugguide.net/node/view/531599 Kind Regards, Christine – San Diego

    Reply
    • Hi Christine,
      Thanks for this update. We also hope you will supply What’s That Bug? with images of the adult Buck Moths when they emerge. We will also try to contact Bill Oehlke to see if he has anything to share or add to this.

      Reply
    • Bill Oehlke supplies a response
      Daniel,
      It is definitely Hemileuca nevadensis for first one
      and for second one as well.
      Bill Oehlke

      Reply
  3. Hi Daniel, I would be happy to add my photos. Thank you for looking at them Bill and posting. Kind Regards,
    Christine

    Reply
  4. Hi, We have found several of these caterpillars in our yard, either hanging out in a Black Walnut, Oak, or Sycamore tree. Ours seem to be lighter, with a yellow body and rows of those scary looking spines. Just FYI, as it is 2013 now and I live in East Sand Diego county (Alpine). Thanks for the info, especially about the color variation. That helped us in identifying this guy in the jar. Also, are they supposed to be large? This one is about 3 inches long. Thanks again, Jenniffer

    Reply
  5. I’m on my way to the “zona de Zongolica, localidad de Ixcohuapa, Veracruz” to study the moth arsenura armida(and particularly reports of the caterpillars being eaten there.
    I would appreciate assistance on (1) exact location and contact information and (2)
    differing reports on toxicity if eaten. Thank you. Tom Jones, Valladolid.

    Reply
    • You are entitled to your opinion, however, when we are conducting a critique of visual imagery, we do not allow our students to make statements that they like or dislike something without providing an aesthetic analysis as to why the imagery is liked or disliked. In the opinion of the editorial staff, the photo clearly illustrates the caterpillar aggregation and it enabled the editorial staff to make an identification. On an unrelated matter, you were unable to complete an eight word sentence without any spelling errors.

      Reply
  6. The only moth that flies in the daylight is the Buckmoth, the Hemilieluca. We filmed them many years ago in Sharon, MA. for Many World’s of Nature, film company owner, Mildred Morse Allen photographer for WGBH Channel @ Boston, MA. Found them mating, laying eggs, hatching, eating the bushes, pupating. I have forgotten the source, possibly one of the Willows and flying in daylight. I would like to know the two food sources that were in our back yard area, high lines, we had both. Wonderful teaching film. Would like the name of the food source they require.

    Reply
    • There are numerous diurnal moths, including Clearwings in the family Sesiidae, like this Virginia Creeper Clearwing pictured on BugGuide and Wasp Moths in the tribe Arctini including the Polka Dot Wasp Moth also pictured on BugGuide.
      According to BugGuide, the larval food for Hemileuca maia, the Buck Moth, is: “Larvae feed on Oaks, Quercus, especially Scrub Oak, Quercus ilicifolia.”

      Reply
  7. Yes there are the scrub oak in our area and definitely remember the Oak leaves on these Srcub Oaks. Did think there was another food source in our area, but the Buckmoths were eating the Oak leaves of the Scrub Oaks that were so close on our land and doing all their things we photographed. Amazing story of these Buckmoth flying around in the daytime. I do not know the other in our MA area that would fly around in Daytime that are mentioned above. We only had the one. Wish I had a copy of her film, it is only fifteen minutes long and has all the important info.

    Reply

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