Care of Silkworms

Care Sheet

Here is a list of the things you will need to take care of your silkworms:

Playtex gloves (with no powder)

Instant sanitizing gel made only with Isopropyl (to use before gloves)

Tweezers (for picking up individual worms)

Isopropyl rubbing alcohol (for disinfecting everything you use)

Microwavable container (for making silkchow)

Metal Whisk (for making silkchow)

Cling wrap (for making silkchow)

The extra things you will need if hatching silkworm eggs:

50 – 100 large Petri Dishes (dependant on the amount of eggs)

Freezer Paper and clear plastic cups (if not using Petri Dishes)

A small cheese grater (for grating the silkchow)

Silkchow or Mulberry leaves (for food)

An incubator
(if the area the eggs are in does not reach the needed temperature of 78-88 degrees Fahrenheit)

Bombyx Mori is the scientific name for the silk moth. The name is Latin and means “Silkworm of the black mulberry tree” Bombyx means “Silkworm”, while Mori means “black mulberry tree.”

Cleanliness:
Silkworms, before becoming moths, are extremely fragile and susceptible to illness. You can not handle them without extremely clean hands, or better yet, wearing surgical gloves, the kind that doctors and dentists use… but without the powder! (You should spray on some alcohol and let the gloves sit for a few minutes to make extra sure they are safe for your silkies.) If you choose to handle them with only washing your hands, please be careful and make sure that the soap you use does NOT have a fragrance left over. The best thing to use, if not using gloves, is an instant gel hand sanitizer. It needs no washing, no water. Just pour some on and rub it around. It can ONLY be the kind made with 70% or higher Isopropyl Rubbing Alcohol, NOT Ethanol! And no added moisturizers!

The best thing to use for picking worms up is tweezers. Long tweezers that you disinfect everyday with Isopropyl. Much easier than washing and wearing gloves every time you want a worm!

NEVER EVER take a worm out of the container, put it somewhere else… and then put it back in the container! That will kill and infect every other worm in there. If a worm falls on the ground, either feed it to a pet right away or ditch it. It can NOT go back in no matter WHAT!

Feeding:
Silkworms must be fed two – three times a day, everyday. Otherwise, you’ll find them eating the cage they are currently living in (if they can get a grip on it). Worms become ill and die with improper feeding. However, larger silkworms can be fed once every other day for slower growth. Smaller worms typically become ill from this.

You can feed them silkchow, which is an artificial diet made from mulberry leaves, or real mulberry leaves. Either way they get the nutrition they need. Some people believe that they get more from the leaves; however, baby worms have a hard time eating the leaves as opposed to the chow. Both types of food have their ups and downs so it’s pretty much a win-win situation.

When feeding silkchow… always keep this rule of thumb in mind whenever you are feeding your worms…

No more than 5 small worms to one square of silkchow.

No more than 3 medium worms to one square of silkchow

No more than 1 large worms to one square of silkchow.

Worms do not have magical powers and 20 of them can not eat from the same piece of food. It’s physically impossible. So always be sure to eyeball the amount of food you are putting in. You want to put enough in there so that they can all get some, but at the same time don’t put too much in because you don’t want to waste the food. Change the food every 5-8 hours.

When feeding mulberry leaves… always take note of the size of the worms you are feeding and use that to determine to size of leaf to use. Babies should have tiny dime sized pieces, medium worms should have half a leaf, and large worms should have whole leaves. Change the leaves every 2-5 hours.

Cooking instructions for Silkchow:
MICROWAVE OVEN (preferred method)

CAUTION: Use at least a 2 litre microwave safe container at least 3 inches deep or it may boil over.

Estimated Time: 6.5 hours. (6 hours cool down - 20 minutes cooking/mixing - 10 minutes prep)

Sterilize everything that will be touching anything having to do with this recipe, with Isopropyl rubbing Alcohol ONLY!! (i.e.. Hands, container, counter, measuring cup, knife, etc)
Measure out 1/4lb of chow (113.40gams - 4oz - 0.5 US cups).
Measure out 1 and 1/2cups of extremely hot tap water.
Pour half of the measured chow into chow container.
Pour half of water into chow container on top of the chow.
Mix with bare hands until smooth (yes you will get messy), knead the mixture turning it often to ensure all dry chow from bottom gets incorporated.
Add remaining chow.
Add remaining 3/4 cup water.
Mix chow as said in step 6 to incorporate all chow into a beautiful even consistancy, should resemble warm green peanut butter at this point.
Smooth out chow to ensure even cooking.
Cover chow container with plastic wrap, tightly.
Place in microwave and cook on high for 3 minutes.
Remove from Microwave when done.
Use a knife and stir the chow folding it over into itself until it returns to a nice even texture, it should now resemble overcooked green oatmeal without the lumps.
Smooth chow back down flat and recover with a new peice of plastic wrap.
Return to microwave to cook on high for 2 minutes. (dont burn yourself)
Remove from microwave and let set (with plastic wrap on!) for 2 hours or until just warm to the touch.
Place in refridgerator until chilled, typically this takes 4 hours.
Remove from fridge, peel back plastic wrap and toss, slice needed amount of chow and serve.
Return unused chow to refridgerator in AIRTIGHT container until needed again.

After the Chow cools, it should have a consistency similar to soft cheese.

For a Printer-Friendly Version of the recipe, click here

IMPORTANT: If the chow you have made does NOT hold together after it has cooled, if it falls apart and seems a bit mushy... DO NOT FEED TO THE WORMS. This food is undercooked and has far too much moisture in it. If the worms are fed this it will increase their chances of becomming ill by weakening their immune system. Please think back and trace your steps, every step in cooking the chow is very important. If you still don't know what went wrong please contact me and I can try to help you figure it out.

WARNING: Do not handle the cooked Chow unless your hands have been thoroughly washed and sanitized. Silkworms are very sensitive and susceptible to bacterial problems if their food is not kept sterile.

NOTE: The cooked Chow will keep for a month or more in the refrigerator if kept airtight. The powder can be stored for about 6 months if kept in a cool dark place, or longer in a refrigerator.

Each 1/4 lb. of powder makes approx. 1.5 lbs. of cooked Chow, enough to feed/grow approx. 350 silkworm eggs into 1 1/2 to 2 inch long worms.

Habitat:
Medium to large silkworms can be kept in Rubbermaid type containers. A preferred way of keeping silkworms is on a frame made with screening inside a box. This way all of the frass (poop) falls through to the bottom for easy clean up. Also, the silkworms wrap silk to the screen more so than wrapping it around each other, otherwise preventing some of them from getting to the food and dying.

Creepy Crawlies offers Custom Made Long-Term Residence Boxes with Screen Frames. We can make them in any dimensions.

You must NOT overcrowd! Overcrowding worms results in disease and death. You can lose an entire lot of silkworms from this. Be very careful. No more than 30 medium sized worms in an area 9” by 7”. Overcrowding is a huge problem when they are brand new little babies.

No matter how old the worm is, before it is placed in the area you are keeping it in, it MUST be disinfected. Watered down bleach or pure alcohol works. If using bleach you MUST rinse with HOT water.. and rinse well! Chemicals are very risky to use with worms sometimes, however, Isopropyl Rubbing Alcohol has been proven to have no harmful affects on silkworms. There is no need whatsoever to rinse the Isopropyl away, just let it sit for 20 minutes and wipe it dry. To dry, use paper towels. It is pointless to go through all of that trouble disinfecting when you turn around and dry it with a household towel or facecloth. That’s just putting germs right back in it. Use common sense.

Reproduction and Cocooning:

1. Cocooning/Spinning:
Silkworms reproduce, but only when they are in “moth” form. To get to this “moth” form… they go through a process called “metamorphosis”. During this process, the silkworm will spin a cocoon of silk around their entire body, encasing them self inside of it. Once encased, the silkworm will continue to spin on the inside of the cocoon, strengthening it. To fully spin the cocoon takes about a day or two. Once the silkworm is done spinning, he/she will then begin “metamorphosis”. Metamorphosis is where the silkworm crawls out of its own skin and slowly, over the course of 2 weeks, turns into a winged moth.
To know when a silkworm is ready to cocoon, they usually do a “big poo”. This is usually very watery and the poop part is white or green. The worms do this to clean out their intestines to prepare for 2 weeks of not going to the bathroom! So when you see that big, wet, white or green poop… you know it’s time! Worms also change their color a bit before they spin. They turn a little transparent and yellow. They also shrink a little. How else would they fit in their cocoons??? =-)

2. Emerging:
The silk “moth” will emerge from its cocoon after 2 weeks of metamorphosis. The moth will discharge a brownish (sometimes clear) enzyme (liquid) on the inside of the cocoon, at one of the ends. This is done to soften the silk so they can emerge easily. They will then try to dig their way out of the cocoon. This can take several minutes, to hours, to even days! Sometimes they require a little help. You can easily poke a little hole in one end of the cocoon and try to stretch it bigger; the moth will soon see the hole and climb out. But be careful not to harm him/her! The moth will emerge damp and bedraggled looking from the enzyme they discharged. After the moth has emerged, he/she will spray the same brownish liquid from their rear. So beware! Don’t try to hold them anywhere near you when they first emerge… it is tough to get the liquid out of clothing! It stains.
Moths can not fly. So whoever tells you they can is lying. It is physically impossible. They just simply can not do it! Their bodies are far too heavy for their tiny, thinner than paper, wings.
Moths emerge blind as well. They find their mates from scent. Moths do not eat. They emerge with only reproductive organs. They have no digestive track, whatsoever. So do not try to feed them! It will not work.
After the moth has fully emerged, it will then sit and rest for a while; they will also continue to stretch out their wings. Female moths have huge egg-laden abdomens whereas the males have a much smaller body.

3. Mating:
When the moths emerge, you can remove them and place them into Petri Dishes. Place one female and one male in the same container. OR, place a sheet of freezer paper down on a flat surface and place a sanitized container ontop of the two mating moths; This helps the eggs to become layed neatly and also helps with removal of the eggs - All you do is cut out the peice of freezer paper with the eggs on it! Before you use any containers, they MUST be sanitized with Isopropyl Rubbing Alcohol. Do not use anything else; anything else will KILL the eggs! Isopropyl is the only safe chemical to use.

Spray Isopropyl all over inside of container and lid.

Wait 20-30 minutes.

Wipe away excess alcohol, but do not rinse.

You’re done!

Silkmoths mate in the most unusual way. To find their mates, they follow scents, or properly called “pheromones”. After emerging, the female moths usually stay very close to their cocoons; they don’t move around much. After she emerges, she will begin to scent. She sticks out a special gland from her abdomen which exudes a pheremone. (this drives the males batty, hence why they flap their wings viciously)
After emerging, the male moths typically don’t go too far from their cocoons… but it is possible. They flap their wings vigorously and walk around in search of a female, following the scent. They will mate with anything even vaguely moth-sized, including cocoons and each another. Once they have found their mate, they try as hard as they can to latch “butts” together. The female usually stays put while the male tries to aim for the right spot. (It is actually quite amusing to watch as sometimes the males miss so bad… that they poke the female in the face!) You can’t blame them for sometimes being bad at aiming, they are blind! But eventually, they find the right spot. Once they have got it, the males flap their wings in short bursts for a while, and then stop altogether.

Now, after they have succeeded at latching together… they may stay like this for several hours to several days. (I had a pair of moths that mated for an entire week!) Once they are done, the male will walk away flapping his wings in search of another female to mate with. But the female whom he just mated with, will go on to lay her eggs. The females lay eggs in a neat and tidy row; pretty impressive for a blind insect! They typically lay around 200-500 eggs, sometimes more, over the course of 2-3 days. The eggs start out lemon yellow, and over a day or two will fade through tan to dark gray or black. If they do not change colors, the eggs are likely infertile. After they change to dark gray, they can be placed into cold storage. Males can mate with as many females as they can until they die. Females only mate once, lay eggs, and then die. Both genders of moths typically live up to 7 days after emerging from their cocoons.

Hatching Eggs:
After the female is done laying her eggs, (you won’t really know until she is dead), you can remove them OR if you had the moths lay the eggs in Petri Dishes, you just place the lid on and there you go! If you had them lay the eggs on the freezer paper, just cut out the peice that has the eggs on it and then place into a container with a lid. To remove the eggs from a container, you must GENTLY rub your finger on them in a circular motion. This will cause them to fall off of the surface. Silkmoth eggs come out with a natural adhesive, which makes them stick to almost anything… thus making it difficult to remove them. Do NOT use your finger nails or any hard objects to remove the eggs, as this may result in the killing and popping of eggs. Place the eggs you have removed into a container that was sanitized with Isopropyl Rubbing Alcohol.

Let the eggs sit at room temperature (78-88 degrees Fahrenheit) for 2 weeks. No more, no less. They should hatch within the two weeks at this temperature, with no problems. IF they do not, you can place them into your fridge (not the freezer!!) for 3-6 months. The main body of the refrigerator can get too cold for them; ideal temperature is between 35F - 40F. After refridgeration, you can incubate the eggs. Thermal Air Flow Hova-Bator Incubator is the only one I would recommend using. For instructions on how to use this incubator with your eggs, please visit: http://www.mulberryfarms.com/faq.htm#4 but do not follow their methods of feeding.
You can tell when your eggs are ready to hatch by their color. Eggs that are within a day of hatching turn a light bluish color, whereas eggs that are within a week of hatching are a darker purplish color.

Raising Hatched Eggs:
When your eggs hatch you will see tiny microscopic black fuzzy creatures. Literally the size of this: -- You can remove the egg shells and un-hatched eggs from the container where the hatched worms are in, or remove the worms and put them into a totaly new sanitized container. If you are removing the un-hatched eggs, place them into a container sanitized with Isopropyl Rubbing Alcohol, incase they hatch later on. To remove the worms, you can use a synthetic sable #1 brush; anything from a #0 to a #2 will work fine. Simply sweep them, gently, and place them into the new container. You may have to brush them off of the tip of the brush, but this method is much easier than using your own fingers which can result in squishing them!

You do not HAVE to remove the baby worms from the egg shells. Moving the baby worms around actually risks killing them or having them become ill. But it is your choice, as it CAN be done.

Silkworm babies must be fed within the first 4 hours of birth. This means, as soon as you see them… feed them!! To feed these little guys, you need a cheese grater and pre-made silkchow. Sanitize your hands, the grater, and everything that has anything to do with the silkworms… with Isopropyl. Take your silkchow and shred up a tiny bit of it with your grater. You can shred it right on top of the worms, or place the tiny pieces in there by hand if you are worried the chow will squish them. (It won’t) Remember not to shred too much food, these things are about the size of a fruit fly, if smaller, and don’t eat that much right now. Feed them 4 times a day to grow them fast, feed them fewer times a day to grow them slow. But I must warn, if you try to grow baby worms slowly… you can make them ill by improper feedings as they are so little and weak. I strongly suggest feeding 3-4 times a day, everyday, at the exact times. The feedings must be on schedule. When you go to shred more food for them, don’t worry about picking out the dry pieces of chow from the last shred. Dry chow will not hurt them, it is dry and will not create mold. You must make sure that the old chow is REALLY DRY. If it still moist you must let it air out and totally dry or remove it altogether.
You can place the lid on their container to keep the food moist for longer, but do not put it on all the way. Put the lid half on, half off. Kind of like how you simmer while cooking. This will prevent too much moisture from forming, too much condensation from forming (they can drown in condensation), and prevent the worms from becoming diseased from mold. When the humidity level is too high in the silkworms environment, their immune systems become weak and sometimes shut down altogether, thus making them even MORE susceptible to illness. So be careful.

Keep feeding the worms this way until they get bigger, about ½ inch to 1 inch long. This is when you can move them into proper housing (a screen frame in a box) and you can start feeding actual cubes of chow instead of shreds. Be sure to keep them at 78-88 degrees Fahrenheit at all times.

Instars:
Instars are the stages of larval development; there are 5 of them between hatch and cocoon, each one accompanied by a new skin and a growth spurt. During growth, the larva (silkworm) will molt 4 times. The period between successive molts is called an instar. To "molt" means to shed.

With the first molt the silkworm loses its hairy exterior, and for the rest of its larval life its skin is soft and smooth.
Every other "Instar" after this is simply the shed of old skin to provide room for the body to grow. The worm, after each instar, will change it's appearance a little. Each time becoming whiter and each time developing markings on it's body. Much like what you see on butterflies.

As silkworms get older, it becomes easier to take care of them… as their immune system gets stronger as they grow; Making them less likely to become ill. But you still must ALWAYS use Isopropyl Rubbing Alcohol. I can not stress that enough!

If you follow everything on this care sheet, raising silkworm eggs will be a breeze! It is a bit hard at first, but you quickly get the hang of it.

Best of luck!

For questions, you can contact me.

Up keep:
Old food and poop can be removed every other day with medium to large silkworms. Make sure to allow the Silkchow to thoroughly dry out before each new feeding. It isn't completely necessary to remove the frass and dry food, but it does aid in not allowing mold to form.

Silkworm poop is called frass. This frass does NOT harm the worms! Many people believe this is the case, but it is not. The frass is only a problem when it sits and sits and forms moisture, thus creating mold. Mold kills worms very quickly. If there is only a small amount of frass in the container, don’t stress over getting it out right away. Old food (silkchow), however, must be removed if it is still wet before the next feeding. If it sits there any longer it molds. If using mulberry leaves, they must be changed up at least twice a day. Silkworms eat A LOT. So be prepared.

If not using a Screen Frame and are using a container or tank:
To remove the frass and old food, make sure you have cleaned your hands and are wearing gloves. (best way to do it) Gently pick up all of the worms and place them all on one side of the container. Scrape all the little round poops together in a pile and scoop it out with either your fingers or a tool of sorts. Gently pick the worms back up, placing them on the side you've just cleaned, and proceed to clean the other side. When you move them from side to side, they all get stuck together in a big ball. I call this the worm ball. When you are done removing old poop, gently spread them all back out.

To remove old food, gently pick up tiny clumps of worms and go through them, one by one, removing old food chunks that are now stuck in the silk they produce, which is typically stuck to their bodies. Be VERY careful, however, not to pull too hard on the silk strands attatched to their bodies, this is how you pull off legs.

As a rule of thumb, make sure everything that touches your silkworms is disinfected. Tweezers, gloves, hands, the tools you use to make/cut your food with, what you carry the food in, etc.. etc.. use common sense.

When silkworms cocoon into silk moths, they no longer need all of the disinfecting. You can hold them and pet them if you please!

And there you have it, Silkworm care 101. If you have any questions or suggestions please feel free to call or e-mail us. Contact information can be located under “Contact Us”.