What Does Silkworm Moths Eat? A Friendly Guide to Their Diet

Silkworm moths play an essential role in the production of silk. As the adult stage of the silkworm, these moths belong to a species called Bombyx mori. While you might be familiar with the silk-producing larvae, it’s interesting to explore what the moths themselves eat during their lifecycle.

During the larval stage, silkworms are known for feeding exclusively on mulberry leaves. However, when they transform into adult moths, their primary purpose is to mate and lay eggs. Surprisingly, silkworm moths don’t actually have functional mouthparts and don’t eat during their short adult lives.

Understanding the silkworm moth’s diet, or lack thereof, is crucial for silk production and the cultivation of these fascinating insects. By focusing on providing optimal nutrition during the larval stage, silk farmers can ensure the healthy development of the moths and the valuable silk they produce.

Silkworm Moth Species

Silkworm moths belong to the order Lepidoptera, which includes both butterflies and moths. There are several species of silkworm moths, some of which produce silk. Here, we’ll discuss a few of them.

  • Bombyx mori: This is the domesticated silkworm moth, well known for producing high-quality silk. They are bred since they are unable to survive in the wild. You may recognize this moth for being used in the silk industry.

  • Bombyx mandarina: The wild silk moth is the closest relative to Bombyx mori. They share the same family, Bombycidae. Unlike their domesticated counterpart, these moths can survive in the wild but produce less silk.

Some moths belong to the Saturniidae family, also known as giant silkworm moths. Common species in this family are Hyalophora cecropia, Eacles imperialis, and Antheraea polyphemus. These moths differ from Bombycidae in appearance and silk production.

To help you further understand the differences between these species, consider the comparison table below:

Species Silk Production Appearance Lifestyle
Bombyx mori High Plump body, dull white or cream color Domesticated
Bombyx mandarina Moderate Similar to Bombyx mori, with more color variations Wild
Saturniidae Low Large, vibrant colors, eyespots Wild

Now you know about some common silkworm moth species, their silk production, and their appearance. This knowledge will help you appreciate the amazing world of these insects and understand their role in silk production.

Life Cycle of the Silkworm Moth

Egg to Larva

Upon laying, silkworm eggs are tiny and fragile. As they hatch, larvae emerge with a voracious appetite. They primarily feed on mulberry leaves for nourishment. During this stage, your silkworm larvae will grow and go through several stages called instars.

Larva to Pupa

As the larva grows, it forms a protective cocoon made of silk. Within the cocoon, the larva undergoes an incredible transformation. This process, known as pupation, is where the plump and nutritious caterpillar turns into a pupa.

The process of pupation

  • Caterpillar spins a cocoon
  • Metamorphosis occurs in the cocoon
  • The caterpillar transforms into the pupa stage

Pupa to Adult

In the final stage of the life cycle, the pupa undergoes metamorphosis to become a silkworm moth. As they emerge from their cocoons, they display beautiful wings. However, the wingspan varies in range depending on the species.

Once an adult, the moth seeks out a mate. The female releases a powerful pheromone, called bombykol, to attract a male. After mating, the life cycle of the silkworm moth starts anew with the laying of eggs.

Adult moth characteristics

  • Fully functional wings
  • Short lifespan, only a few weeks
  • Does not feed during adulthood

By understanding the life cycle of the silkworm moth, you can better appreciate their growth, resilience, and ecological importance.

Silkworm Moth Diet

Silkworm moths mainly feed on mulberry leaves. However, they can also consume other soft leaves like lettuce, violet leaves, and beetroot leaves1. For instance, young silkworms can adapt their diet to include various options.

When you don’t have access to mulberry leaves, you can consider feeding your silkworms with other options like:

Remember to provide fresh, clean, and pesticide-free food for your silkworms. This ensures their proper growth and overall health.

Although silkworms can survive on alternative food sources, optimum nutrition and growth are achieved when feeding on mulberry leaves2. This is because mulberry leaves provide all the essential nutrients required for their development.

Food Source Pros Cons
Mulberry leaves Optimal nutrition and growth Limited availability
Lettuce Easy to find Less nutritional value compared to mulberry
Silkworm chow Convenient and available all year Might not be as effective as mulberry leaves

You can use a combination of these food sources to maintain a balanced diet for your silkworm moths. Ensure you always monitor their growth and development to provide them with the best possible diet.

Threats to Silkworm Moths

Silkworm moths face various threats in their environment, which can impact their population and survival. Some of the most common dangers come from diverse predators, including reptiles, spiders, amphibians, and even mosquitoes.

For example, reptiles such as lizards are known to prey on silkworm moths. These cold-blooded creatures have an appetite for insects, making moth larvae a tasty meal for them.

When it comes to spiders, their webs are a common trap for silkworm moths. Once caught in these silky threads, the moths are incapacitated, and the spiders can quickly devour them.

Amphibians, like frogs and toads, are also known to eat silkworm moths. Frogs can quickly snatch them out of the air with their long, sticky tongues. Similarly, toads tend to wait for moths to come within striking distance and then eat them with their speedy, powerful tongues.

Snakes are less likely to target silkworm moths but still pose a threat, especially to moth larvae. Small, insect-eating varieties of snakes will occasionally consume silkworm moth larvae that they find on the ground or lower branches.

Lastly, even mosquitoes can be a danger to silkworm moths during their larval stage. Some mosquito species feed on insect larvae, including those of silkworm moths, impacting the moth’s development and population.

Silkworm and Silk Production

Silk Production Cycle

In sericulture, you will find that the silk production process involves breeding domesticated silkworms. Silk moths lay eggs, which hatch into larvae and eventually grow into silkworms. These silkworms spin cocoons, which are then harvested for silk threads. To ensure high-quality silk, farmers practice selective breeding and sometimes employ genetically modified silkworms.

Let’s take a look at the steps involved in silk production:

  1. Silk moth lays eggs
  2. Eggs hatch into larvae
  3. Larvae grow into silkworms
  4. Silkworms spin cocoons
  5. Cocoons are harvested for silk threads

Silk Quality Variation

The quality of raw silk produced can vary depending on factors such as the methods employed by farmers, the type of silkworms, and the overall sericulture practices. Some factors that influence silk quality include:

  • Selective breeding for desirable traits
  • Genetically modified silkworms for improving silk quantity
  • Proper care and feeding of silkworms
  • Optimal conditions for cocoon spinning

Silk production holds significant economic importance, and its quality is directly related to the value of the fabric. Remember that investing in good breeding techniques and sericulture practices can make a big difference in the quality of silk fabrics you produce.

Geographical Distribution

You may wonder where silkworm moths can be found around the world. These fascinating creatures have a wide range of distribution, spanning various countries and continents.

In Asia, silkworm moths hold a significant presence. For instance, in China, they have been an important part of the country’s culture for thousands of years. You can also find them in India, Japan, and Korea. Due to their role in silk production, their cultivation in these regions has greatly influenced the economies and traditions.

In North America, you will also encounter silkworm moths species such as the polyphemus moth and the luna moth. These moths, like their cousins in Asia, play a valuable role in the ecosystem.

As for the West, including the Khotan oasis, these moths are limited, mainly due to climate and availability of suitable host plants for their caterpillars.

To summarize, the geographical distribution of silkworm moths covers:

  • China
  • India
  • Japan
  • Korea
  • North America

Keep in mind that while silkworm moths can be found in various locations, their specific habitat preferences might differ due to climate, host plants, and other environmental factors. Happy exploring!

Silkworm Moth in Culture

Silkworm moths have a rich history in human culture, particularly in the realms of silk production and cultural cuisine. Their domestication has led to fascinating developments in art, textiles, and sustainable food sources.

The domestication of silkworms began thousands of years ago in China. The finest silk fabrics come from the cocoons of these domesticated moths, known as Bombyx mori. Silk production has also influenced animal welfare practices – breeding and rearing techniques have improved, ensuring the well-being of these insects in captivity.

In some cultures, silkworm moths are a source of protein. Two popular dishes featuring these insects are beondegi and tsukudani. Beondegi is a Korean street food made by boiling and seasoning silkworm pupae, while tsukudani, a Japanese dish, involves simmering the pupae in soy sauce and sugar.

These insects hold a special place in folklore too, like the tale of the princess who discovered silk. In this story, a Chinese princess named Leizu was drinking tea under a mulberry tree when a cocoon fell into her cup. As she pulled the cocoon out of the tea, she discovered the fine silk thread, marking the beginning of silk cultivation.

Here are some key points about silkworm moth culture:

  • Domesticated primarily for silk production
  • Cultural cuisine includes beondegi and tsukudani
  • Significant role in folklore, such as the tale of Princess Leizu

As you can see, silkworm moths are more than just insects – they have played an essential role in the development of human culture and creativity throughout history.

Footnotes

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

  2. https://pubmed.ncbi.nlm.nih.gov/33266201/

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 – Mopane Worm from Namibia

 

Subject: ”Mopane Worm” from Namibia
Location: Namibia: Damaraland: Hobatere Lodge, 80 km N of Kamanjab
March 18, 2013 4:43 pm
Here’s a photo of a ”Mopane Worm” I mentioned in a comment I just posted about a similar caterpillar from Tanzania. This is Gonimbrasia belina (Saturniidae), on Mopane, its namesake foodplant (Colophospermum mopane; Fabaceae), at the Hobatere Lodge, ca. 80 km N of Kamanjab, Damaraland, Namibia, on 26 March 2010.
Signature: Julian Donahue

The larvae are collected, dried, and highly prized as food (tried one, but too “spiky” for me to really enjoy).

Mopane Worm
Mopane Worm

Hi Julian,
Thanks so much for submitting this beautiful photograph of such a stunning caterpillar.  We see the resemblance to the Tanzanian Caterpillar we just posted.  The adult moth is pictured on the African Moths website.

Letter 2 – Green Striped Mapleworm

 

Subject: Can’t identify this caterpillar
Location: Athens Georgia
August 28, 2016 10:07 pm
Ok so I have spent about an hour and a half trying to I this caterpillar and the closest thing I can find is an orange striped oak worm BUT this is not orange, has a tighter paternity and is smoother. The top lines are white and turn yellow towards the legs. It has one set of horns and multiple small pounds on its tail. Also it has a red marking on both sides of the tail at the bottom near legs. These things are devouring my maple tree and have turned the concrete on my patio black
Signature: Tony Bowers

Green Striped Mapleworm
Green Striped Mapleworm

Dear Tony,
We found an image of a Green Striped Mapleworm on the Post and Courier website, and we then researched that on BugGuide where we learned this is the caterpillar of the lovely Rosy Maple Moth,
Dryocampa rubicunda.  According to the Forest Insect & Disease Leaflet 77:  “The green-striped mapleworm (Anisota rubicunda (Fab.) ), a native of North America, is distributed widely throughout the eastern half of the United States and the southern parts of adjacent Canadian Provinces. Its southern range extends from the Carolina coast to the gulf coast in Alabama and Mississippi. It has been recorded as far west as Nebraska and Kansas.  The insect causes heavy defolia­tion throughout its range but is most destructive near its southwestern limits.”  You should note that the genus name is incorrect in the latter link.  Though we have numerous images of the adult Rosy Maple Moth on our site, we believe this may be a first for the Green Striped Mapleworm.

Letter 3 – Mystery Striped Caterpillar Aggregation from Chacchoben: Arsenura armida

 

strange caterpillars
I realize you are super busy and you may not get to my request. I recently found your site and its terrific. I am a high school Biology teacher and plan to use the website somehow during the year! Now, to my request: I just returned from a vacation in the Caribbean and Mexico. While visiting the Mayan ruins at Chacchoben in the Yucatan, I noticed this cluster of caterpillars. We were on a tour and couldn’t linger but I managed to snap the attached picture. I pride myself in being able to find anything on the Internet, but alas I have been unable to identify these strange creatures. I have also consulted several books on the subject and have come up dry. I am starting to think they aren’t even caterpillars. Can you help? Thanks,
Sarah S.
Bakersfield CA

Hi Sarah,
How can we help but to try to come to the assistance of someone who uses the word “Alas” in a plea? First, there isn’t much documentation of rain forest species. Even if the adult is known to science, the life cycle might not be documented. Our first inclination was that perhaps this is some relative of the Tetrio Sphinx, Pseudosphinx tetrio, but we couldn’t locate any relatives. The red terminal pro-legs and coloration led us on that tract. Then we thought there was a resemblance to the Cucullia species caterpillars we know from the U.S. Those are our two best guesses. We will post your image in the hopes that readers out there have too much time on their hands and are able to find an answer. Please let us know if you find the answer.

Update: (06/30/2008) Arsenura armida Caterpillars
With our fourth submission of Caterpillar Aggregation images, we are convinced that this species is Arsenura armida, a Neotropical Silkmoth that ranges from tropical Mexico to Bolivia and Southeastern Brazil. We just located a website with valuable information written by James T. Costa , Department of Biology Western Carolina University, Cullowhee, NC.

Letter 4 – Sphingicampa Caterpillar

 

Subject:  Caterpillar
Location:  22nd/Craycroft, Tuscon, Arizona
August 28, 2017 12:40 AM
Do you know what type of caterpillar this is? Found it round the 22nd/Craycroft area, is it poisonous? The stripes on his body was silver looking but not in the pic.  Thx. Did ya get my other pics on your site?
Signature:  Diane Minten

Sphingicampa Caterpillar

Dear Diane,
In the future, please use our standard submission form for new submissions (Ask What’s That Bug? link on our site) because tacking on a new series of images to a previous response we have given on an unrelated species creates problems for us when creating new postings.  We had no idea where 22nd/Craycroft is located, which forced us to use Google Maps to determine it is in Tuscon, Arizona.  This caterpillar is in the genus Sphingicampa, and the Saturniidae of Arizona page indicates four species found in the state:  “
Sphingicampa albolineata: July-August, Sphingicampa hubbardi: July-August; southwestern half, except extreme west, Sphingicampa montana: July-August; extreme south, Santa Cruz, Sphingicampa raspa: July-August; extreme south, Santa Cruz.”  Your early instar caterpillar does not look exactly like any images posted to the site and we may try to contact Bill Oehlke to get a species identification.  We believe your individual most closely resembles this image of Sphingicampa albolineata that is pictured on BugGuide.  It is not poisonous.  We have nearly 25,000 unique postings to our site.  We don’t know to which other “pics” you are referring.

Sphingicampa Caterpillar

Bill Oehlke provides a different identification.
I am more inclined to think raspa, but I am not sure. There is probably some variability among larvae of each individual species.

Letter 5 – Striped Caterpillar Aggregation from Mexico: Arsenura armida

 

Massed Larvae in Coba ruins (Coba Q.R)
The attached photo was taken in the Coba ruins near the small town of Coba on the Yucatan Peninsula the summer of 1999. I came across the transparency recently cataloging old images. These are massed larvae of some insect, I suppose butterfly or moth, on the trunk of a tree, several feet off the ground. The scale is not obvious from the photo although some idea is gotten by noting the reticulation of the tree bark but they were very large. The larvae (caterpillars) were at least 6 inches long and round about as a man’s thumb. I’ve never seen anything like it before or since. The size of the the individual larvae and the extent of the larva mass was striking. Do you have and identification?
Philip Brody
Bethesda, Maryland

Hi Philip,
This is the third request we have received over the years for the identification of this species, each time with an excellent photograph. Though we have tried for hours, we have never been able to identify this species. The more recent request arrived two weeks ago, and the original request came in August 2006. This is probably our most nagging yet unidentified species, and we hope one day to have the answer.

Update: (07/15/2007) Mystery Striped Caterpillar Aggregation from Chacchoben
Mystery Striped Caterpillar Aggregation from Chacchoben (08/04/2006) strange caterpillars Possible identification of aforementioned: Arsenura armida www.saturniidae.com www.insectcompany.com/silkmoth /kwaarmida.htm Best of luck!
PCG
PS Saw your interview in the July 2007 issue of Sunset magazine—kudos!

Dear PCG,
The links you provided did not have caterpillar images, but we did a websearch and were led to a page with many caterpllar images of Arsenura armida. Though they look similar, we are not thoroughly conviced this is the species we have received three images of thus far. Glad you saw the Sunset Magazine interview.

Update: (06/30/2008) Arsenura armida Caterpillars
With our fourth submission of Caterpillar Aggregation images, we are convinced that this species is Arsenura armida, a Neotropical Silkmoth that ranges from tropical Mexico to Bolivia and Southeastern Brazil. We just located a website with valuable information written by James T. Costa , Department of Biology Western Carolina University, Cullowhee, NC.

Letter 6 – Shag Carpet Caterpillar from Guatemala

 

Subject:  Fuzzy reddish/orange, black and white caterpillar
Geographic location of the bug:  Rio Dulce, Guatemala
Date: 02/19/2019
Time: 08:01 PM EDT
Your letter to the bugman:  Found this caterpillar inching along the ground today (feb 19, 2019) and haven’t had any luck figuring out what type it it! I thought maybe in the Tussock family?
How you want your letter signed:  Emily

Shag Carpet Caterpillar

Dear Emily,
This is a very distinctive and impressive looking Caterpillar.  Our first hunch is the superfamily Noctuoidea which includes the Tussock Moths.  We will attempt to provide you with a species identification, and perhaps our readership will be able to provide some information.

Facebook Comment from Karla Thompson
Prothysana felderi.
Shag Carpet caterpillar.

Update
We learned the Shag Carpet Caterpillar is in the family Apatelodidae, the American Silkworm Moths.  According to All About Butterflies:  “The larva of 
Prothysana felderi varies in appearance from instar to instar. It also occurs in various colour forms across its geographical range. Some varieties have a buff or olive ground colour, with tussocks of red setae on the thoracic and anal segments, while others are deep red, with ribbons of black or white setae along the backs.  The larvae feed on Philodendron, Heliconia, Welfia, Aegifila, Chamaedora, Piptocarpha, Pentaclethra, Piper, Stigmaphyllon, Neea, Lycianthes, and Heliocarpus.”  

Letter 7 – Velda Pine Moth Caterpillar

 

Big Bear Caterpillar
Location: Big Bear Lake, CA (San Bernardino National Forest)
January 29, 2011 1:58 am
I saw an interesting looking caterpillar when I was hiking near Big Bear, CA. Later we saw the same type of caterpillar rolling down a hill, doing their best to rid themselves of a bunch of red ants.
Signature: Sat Garcia

Velda Pine Moth Caterpillar

Dear Sat,
We quickly identified your caterpillar as the Velda Pine Moth Caterpillar,
Coloradia velda, on the private World’s Largest Saturniidae Site, and we are linking to images on the Santa Clarita and Northern Los Angeles County Area Butterfly and Moth SiteYou may view dozens of photos documenting the metamorphosis process of the Velda Pine Moth there.  Adult moths do not eat but the gregarious caterpillars feed on the needles of a number of native pines.

Authors

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  • 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.

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  • 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.

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