- Silkworms Diseases and Problems
- Experiencing Problems? Have some of your silkworms died? or are they looking a little sick? Please read
- The number 1 most important rule in rearing Silkworms is Hygiene!
- This means personal Hygiene, washing hands with soap and drying your hands completely on a clean dry paper or
- cloth towel BEFORE handling silkworms.
- It also means keeping the breeding container for your silkworms CLEAN.
- If using cardboard boxes it is important to obtain boxes that are clean and dry without contamination of any type.
- The boxes can be lined with clean paper towel which gives an added sterile layer between the worms and the
- cardboard and also helps to absorb moisture.
- If using plastic tubs or glass terrariums it is important that they are cleaned thoroughly with soap and water and
- dried completely before the silkworms are placed in them (Silkworm industries always use bleach). Again paper towel
- can assist to keep the worms moisture free. It also assists in removing the leftover mulberry and frass when cleaning.
- Common Problems
- Eggs do not hatch
- Such as exposure to heat from lamps or sunlight in which case eggs will go a reddish colour appearing flat rather than
- rounded and plump (small indents in the top of eggs that are a normal grey blue colour are not a problem).
- Exposure to condensation or water
- In which case eggs will go a darker grey blue colour and will swell to larger than normal size – eggs will not hatch.
- This may occur from high levels of humidity in the breeding container resulting in condensation and pooling of water.
- Ensure ventilation of breeding container minimum twice daily. If using a damp piece of towel in breeding container to
- increase the humidity ensure eggs do not contact the damp cloth.
- If eggs become wet accidentally and are quickly dried they will still hatch. Pat dry with paper towel with very light
- pressure to prevent bursting of eggs.
- Exposure to pressure
- In which case eggs will burst and appear flattened, the fluid from within the eggs will be visible – eggs will not hatch.
- Cold temperature in breeding area
- Temperature below 26 degrees c can cause eggs to stay unhatched for a longer than usual period.
- Ensure a daylight photoperiod of 12L:12D (as in equal length of day and night).
- Increase ambient room temperature without exposing the eggs to any direct heat from lamps or sunlight.
- Hatchlings shrivel and die.
- Hatchlings disappear.
- This is usually the result of ant attack, particularly if you are in WA, NT or QLD. Other insects may also take your
- hatchlings. Use a water bath to prevent this. To use a water bath fill a large plastic tub or tray with water, place the
- breeding container on top of a brick or upturned pot that is placed in the water bath. Ensure worms cannot fall into the
- water bath and drown.
- Silkworms writhe/flip back and forth and vomit gut juice.
- This is caused by INSECTICIDE on mulberry leaves. It is a very sad way for silkworms to die. If you are unable to
- ascertain whether a mulberry tree has or has not been sprayed please batch test the leaves with only a few silkworms
- first. If the leaves are sprayed the silkworms will show symptoms within 6 – 12 hours of eating the leaves depending
- on the potency of the insecticide residue on the leaves.
- Fortunately the worst of the silkworm diseases are not present in Australia. It is for this reason that importing
- silkworm eggs is restricted.
- Disease can be circumvented by strict hygiene and quality mulberry feed either with quality fresh leaf or chow. Strict
- hygiene is also necessary when preparing and feeding silkworms with chow.
- Problem: Worms appear lethargic and flaccid, growth is stunted. The cephalothoracic region may be translucent.
- Worms vomit gut juice (green to brown yellow), develop dysentery and excrete chain type fecus. Dead worms putrefy
- quickly often with a foul odor. The colour of dead worms is black/brown, if you try to lift a dead worm it will break
- open. Dead worms break open when healthy worms walk over them covering the healthy worms in fluid.
- Name and Cause: Flacherie: Bacteria and viruses cause the disease individually or in combination. Flacherie is most
- often caused by high humidity and fluctuating temperatures. Flacherie is also caused by mould, fermentation and
- humidity build up in waste mulberry and frass. It is most often seen in the 4th and 5th instars but can occur in the
- earlier instars. If your silkworms get infected during the 3rd , 4th or early 5th instar, symptoms of the disease will be
- observed prior to spinning or pre-pupal stage. If the infection is in the late 5th instar, the mortality will be in the pupal
- stage in which case your cocoons will not hatch, this is most often identified by your cocoons emitting a foul smell.
- Changing from coarse Mulberry to tender Mulberry leaf favours the disease development especially if the change is
- made abruptly after feeding coarse leaves for sufficiently long time.
- Solution: As Flacherie is most often contracted in the early Instars and does not present until the later instars it is
- usually impossible to eradicate without destroying the entire colony. You may remove the sick or dead silkworms and
- any silkworms that have contacted fluid. Wash hands carefully before handling healthy worms. Dispose of dead or
- sick worms by either burying 2 feet or more underground, double bagging and placing in the outside rubbish bin or by
- If you choose to destroy the whole colony place all worms in a bag and place into the freezer.
- Before raising any more silkworms ensure your breeding area, plastic tubs and terrariums have been cleaned with
- bleach. It is best to wait 3 months before rearing more silkworms.
- Problem: Silkworms are sluggish with swollen intersegmental region, The integument of diseased larvae are fragile
- and breaks easily, a milky fluid oozes out from the larval body, the diseased larvae do not settle for moult and show
- shining integument, the larvae appear to be restless, the dead larvae hang by hind legs head downward. Basically if
- your worms will not spin and just die, this is the cause. In silkworms infected with a high dose of virus, the ecdysone
- hormone required for moulting and maturation will be destroyed. The larval period will be simply continued indefinitely
- due to lack of ecdysone till the larvae develop the disease. This is why we see the disease associated with worms
- that fail to moult and spin their cocoon. If the infection level is low, larva pupate will die in pre-pupal or pupal stage.
- Name and Cause: Grasserie: The Grasserie disease is caused by a virus – Nuclear polydedrosis. Grasserie is similar
- to Flacherie in that poor hygiene and poor Mulberry Quality contribute as well as humidity and temperature
- fluctuations. Avoid high ( 28-35C), low rearing temperature ( 10-20 C) and rearing humidity ( <70%). As for Flacherie.
- Solution: As for Flacherie.
- Problem: The diseased silkworms prior to death will be lethargic and on death are flaccid, oil specks may be seen on
- the surface of silkworms, they gradually become hard, dry and mummify into a white or green coloured structure.
- (please see image) The diseased pupae will be hard, lighter and mummified.
- Name and Cause: White Muscadine is caused by a fungus Beauveria Bassiana and the Green Muscadine is caused
- by a fungus Spicaria Prasina. Aspergillosis is common in young age Silkworms and the infected larvae will die. Dark
- green ( Aspergillus Flavus) or rusty brown ( Aspergillus Tamari) Mycelial cluster are seen on the dead silkworm
- body. Caused by the fungus being present on the mulberry leaf transported there by other insects.
- Solution: Hygiene. Prevent Humidity build up. Keep mulberry tree’s free of insects (without the use of insecticides as
- this will kill your silkworms). Muscardine is common in winter and rainy seasons because these seasons provide
- favourable environments for infection, growth and multiplication of the pathogen.
- This type of dead Silkworm is the source of the traditional Chinese Medicine “bombyx batryticatus” or “stiff silkworm”.
- It is the dried body of the 4~5th stage larva of silkworm died of the white muscadine disease which is caused by the
- infection of the Beauveria bassiana . Its uses are to dispel wind, dissolve phlegm and relieve spasm!
- Experiencing Problems? Have some of your silkworms died? or are they looking a little sick? Please read
- The Secrets of Raising Silkworms
- Worm Incubation
- Care and Feeding
- Pupa Preparations
- The Harvest, and After
- Make Your Own Tools!
- A New Generation
- All Around the Mulberry Bush….
- silk making step 1: raising silkworms and harvesting cocoons
- How is silk made?
- Can silkworms feel pain?
- What about silk’s costs and benefits to humans?
- What are the alternatives to silk?
- It’s complicated
- Silkworm moth
- Silkworm Care Sheet
- Why Raise Silkworms?
- How To Get Started
- Caring For Silkworms
- More Information
Silkworms Diseases and Problems
Experiencing Problems? Have some of your silkworms died? or are they looking a little sick? Please read
The number 1 most important rule in rearing Silkworms is Hygiene!
cloth towel BEFORE handling silkworms.
It also means keeping the breeding container for your silkworms CLEAN.
cardboard and also helps to absorb moisture.
Eggs do not hatch
Exposure to condensation or water
increase the humidity ensure eggs do not contact the damp cloth.
pressure to prevent bursting of eggs.
Exposure to pressure
Cold temperature in breeding area
Temperature below 26 degrees c can cause eggs to stay unhatched for a longer than usual period.
Ensure a daylight photoperiod of 12L:12D (as in equal length of day and night).
Hatchlings shrivel and die.
In this case it is very simple, your silkworms have not had enough to eat and have died. There is no disease present
in Australia that kills silkworm hatch-lings, so malnourishment is the main cause of hatch-ling death other than ant
attack. Other causes are excessive moisture or heat.
water bath and drown.
Silkworms writhe/flip back and forth and vomit gut juice.
on the potency of the insecticide residue on the leaves.
image: insecticide poisoning will cause your silkworms to vomit and writhe
silkworm eggs is restricted.
hygiene is also necessary when preparing and feeding silkworms with chow.
open. Dead worms break open when healthy worms walk over them covering the healthy worms in fluid.
made abruptly after feeding coarse leaves for sufficiently long time.
If you choose to destroy the whole colony place all worms in a bag and place into the freezer.
bleach. It is best to wait 3 months before rearing more silkworms.
image: flacherie will cause your silkworms to putrify
Solution: As for Flacherie.
image: grasserie virus
(please see image) The diseased pupae will be hard, lighter and mummified.
body. Caused by the fungus being present on the mulberry leaf transported there by other insects.
favourable environments for infection, growth and multiplication of the pathogen.
image: white muscadine
The Secrets of Raising Silkworms
You may be able to locate silkworm eggs through your local spinning and weaving organizations. It these sources don’t pail out, though, you can write to Marguerite in Pasadena or Mary. Both women will be glad to share their knowledge and egg supplies, but be sure to send a self-addressed, stamped envelope—and at least $2.00—with any request for eggs or information.
Then, should your packet of “silkworm seeds” show up before the local mulberry trees are in leaf, keep the embryos at about 50°F (just place the paper towel or napkin—on which the eggs arrive—in a sealed jar, and store the container in the crisper compartment of your ‘fridge) until it’s time to hatch them.
Once your trees have produced a good supply of feed, it’s time to “plant” your silk crop. Simply place the eggs—still on their paper—in any available container (such as a shoebox or dishpan) and put ’em in a warm, dry, well ventilated spot. It’s very important to keep all the eggs, worms, cocoons, and moths out of drafts and direct sunlight. They do need plenty of fresh air, so it’s best not to smoke around silkworms at any stage of their development. The temperature of the incubating box should be increased gradually over a couple of days, and then ‘maintained as nearly constant as possible. Anywhere from 68 to 77°F will do.
After three to ten days in the box (depending on warmth, humidity, and other factors) the majority of your eggs will hatch within one ten-minute period, usually during the early morning. This means that you can wake up to find that you have 200 very hungry mouths to feed! Any worms that don’t hatch out with the first group probably won’t put in their appearance until the following day. These late eggs should be placed in another box, since they’ll be on a different molting and spinning schedule from the first-born
Keep in mind that your infant silkworms will be less than 1/8 of an inch long. Yet, one short month later the critters will have attained 10,000 times their initial weight. All that growth has to be fueled with mulberry leaves.
Care and Feeding
For your worms’ early feedings, remove the leaf stems and use only the tenderest top-of-the-tree leaves (remember to strip the branches from the base to the tip in order not to tear the bark or injure new buds). Such “starter feed” should be chopped into 1/4-inch squares and—if there’s even a chance that the bush has been sprayed—washed and thoroughly dried before the fodder is sprinkled evenly about the box. It’s best to pick the leaves fresh each day, but an emergency supply can be stored in the crisper of your refrigerator if, again, the greens are dried out before they’re offered to the hungry little critters.
The more your new charges eat, the bigger they’ll get and the more food they’ll require. If you underfeed the worms at any point, they may become so ravenous that they’ll overeat at the next meal and make themselves sick. Constant underfeeding can even lower the quality of their silk! The trick is to give your worms adequate, regular feedings, never let them run out of food, and always remove old, wilted leaf pieces from the box.
In addition, the silkworms will be healthier if you clean their “litter” by regularly sliding in fresh, dry pieces of paper and removing (to the compost pile) the soiled sheets. When this isn’t done, molds can form that could give rise to a number of worm diseases.
Though the caterpillars seem to eat more in the mornings and evenings, they’re actually chowing down at all hours. The only times the worms will stop chewing are during their four molting periods, which occur about every five or six days.
Shortly before each molt, the heads of the worms will swell, their skins will lose color, and their bodies will become transparent and immobile. (It’s extremely important that the larvae aren’t moved or disturbed in any way at this time.) During the 24-hour “skin-shedding process” your wigglers will go into a sleep and lose all interest in food. Otherwise, their appetites are regular and enormous.
Mary Stock reports that silkworms get especially voracious in the last week before they start to spin. While in this stage her 10,000 charges consume two and a half bushels of mulberry leaves a day. Though Mary already has 15 trees on her 25-acre farm, she’s in the process of planting 25 additional seedlings! (Besides providing worm food, the trees make great windbreaks and produce quantities of useful berries.)
As the caterpillars increase in size, divide the brood into several containers. Each individual needs space to grow. You’ll want to avoid conditions that force the critters to crawl over each other, because their velvet skins are so delicate that even silkworm feet can tear them. When you transfer the fragile larvae, it’s best to wait until they climb onto their food and then remove each worm—leaf and all—to new quarters.
Once the “spinning time” approaches (after three weeks or so) provide containers with lots of edges, so your wiggly weavers can quickly set up the “guide wires” from which they’ll hang their silken shelters. A number of small strawberry boxes or egg cartons will be fine for this purpose.
Then suddenly—anywhere from 25 to 32 days after hatching—your caterpillars will stop eating and start to produce silk.
You’ll be able to tell when a worm is ready to spin, because it will appear sluggish. Often the critter’s head will move from side to side as it seeks a suitable location for its new home. (Since the larvae have no eyes, try to make sure that they don’t have to travel far to find a suitable corner.)
A silkworm “sets up shop” by secreting a filament from an orifice located just below its mouth. As strands leave this opening, they make contact with another secretion called sericin which becomes sticky when it’s exposed to the air. This “glue” allows the incredible little workers to set their guide wires and shape their cocoons.
After the caterpillar has anchored its crude hammock, it will lie on its back, double up its legs, contract its body, and force the filament from within. The small spinner won’t take the easy way out and weave Its womb in circles from one end to the other. Instead—with its head bobbing and weaving at a rate of 69 times per minute—the amazing creature produces a pattern of figure eights, layer upon layer, until its shell is formed.
You’ll soon lose sight of the hearty worker but will still be able to hear it spinning until its complete supply of body fluids so magically created from mulberry leaves is consumed. If you could see inside the finished case, you’d find that the once-plump, three-inch-long caterpillar has been transformed into a shriveled-up pupa of about 1 1/4 inches in length. The entire spinning process takes about three days, and it’s a show that beats the stuffing out of anything on television!
The Harvest, and After
While the tired pupa turns itself into a moth—a process that takes from ten days to two weeks—you’ll have a decision to make: If you plan to raise silkworms again the following year, it’ll be necessary to select some cocoons that will be allowed to complete their life cycles.
Naturally, it’s necessary to choose a fairly equal number of males and females to carry on your line, and the best way to sex these critters is to take a close look at their protective envelopes. A male produces a structure that resembles a peanut slightly hour-glass in shape and somewhat pointed at the ends—while the “ladies” are most often found in larger, oval-shaped sheaths. Keep in mind that one moth lays from 300 to 400 eggs, and that 80 or 85% of those will hatch. Two dozen cocoons will, therefore (assuming that half of them contain females), yield enough “seed” to hatch about 3,000 crawlers.
The nests that you select as your “laying stock” should be removed from their boxes and set aside in separate, clean, dry containers. There’s no trick to plucking the little silk houses from their moorings … just tug ’em gently and they’ll release. (Some waste silk will cling to the box and cocoon, though. Pull this material loose and save it, as it can be woven into a beautiful rough cloth called shantung.)
Traditionally, the rest of the cocoons—which vary in color from light brown to creamy white, with a little lemon and pale green thrown in—are harvested anywhere from seven to ten days after the caterpillar begins to spin. It’s necessary to kill the pupas inside those nests that are to be used for silkmaking. (If you don’t, the chrysalids will soon emerge as moths, and—during this process—the insects produce a solvent which destroys the continuous filament of the silk fiber.) The easiest way to accomplish this unpleasant but necessary task is to put the cocoons in a paper bag and place the sack in a 200° F oven for 20 minutes. Long exposure—at least six hours—to bright sun will also do the job.
After the pupas are killed, you can relax for a few days before you reel and spin your silk. But don’t rest too long, or the material will take on a distinctive aroma from the dead chrysalids inside.
And what kind of harvest can you expect ? Well, perhaps not much the first year (it takes about 2,000 cocoons to produce a pound of raw silk, and some 350 to make a pair of stockings! ) but enough of a crop to see whether you really enjoy the art of sericulture.
Make Your Own Tools!
One of the great things about harvesting silk is that most of it can be reeled directly from the cocoons with a simple homemade tool. Just find yourself two dark-colored pieces of paperboard—each about 10 inches square—and a short stick or clothespin. Cut a slot halfway to the center of each board, and interlock the two sections so they resemble the paddle wheel of a boat. Then, to make a “twirling” handle, clip a clothespin just above or below the intersection of the squares (or cut a slot in a dowel or stick and slip that handle in place).
Next, bring a small pan of water almost to a boil. (If you use a container with a dark interior, you’ll find it easier to locate the filaments of silk.) When the liquid is ready, drop five to eight cocoons—depending upon how heavy you want your thread to be—into the, pan. Most commercial silk is eight strands thick, but five fibers will also work well; the incredible strength of each strand is equal to (or greater than) that of a filament of steel of the same diameter!
After a few minutes the water will begin to dissolve the glue, and you’ll see the tiny strings float away from the cocoons. Use tongs to catch the filaments, twist them together in the fingers of one hand while your other hand slowly reels the thread onto the paperboard spool. When you get to the end and the pupas drop into the water, tie a small knot to keep the thread from unraveling. (Remember, you’ll be winding 600 to 1,000 yards of silk, so start the job in the morning. Don’t wait till an hour or so before bedtime! )
The reward for your (and the silkworms’) labor is a thin, continuous thread of the finest material available. Silk weighs less than any natural fiber, yet a strand thinner than a human hair can be stretched five to six inches a yard and still return to its original length!
When we visited Mary Stock, she showed us the ancient art of “skin spinning” the waste silk. Here’s how to do it: Take a short, straight piece of coat hanger and make a slight hook (about 1/4 inch across) at one end. Then, use this tool to pull at the bundle of raw silk you’ve accumulated. As you separate a thin string of fibers from the mass, roll it on your leg to form a strand. You can also use a drop spindle, or even comb the waste silk with a cotton-carding tool and spin it on a wheel. Remember that silk is an extremely fine fiber, though, and must be handled with care.
The silkworm’s sticky sericin—some of which will remain on the filaments—makes the thread a bit stiff and lackluster. However, it’s best to weave the silk before you give it a final wash in mild soap and water to remove this gluey substance.
A New Generation
Meanwhile, back at the breeding box, you can watch the Bombyx mori—the mulberry or silkworm moth—put in its brief appearance. The “great awakening”—as the Chinese called this event—takes place as the moth secretes its alkaline saliva, which softens the end of the cocoon and allows the adult insect to step into the world.
The wings of the male moth have a distinct sickle shape, and will soon dry and grow as the insect flaps them. The females can be easily identified by their larger abdomens. Neither sex is able to fly, and the “ladies” rarely stray more than a few inches from their cocoons.
Since the moths are not equipped to eat and sustain themselves, mating and egg-laying take place soon after they emerge from their cocoons. Be prepared—by placing some paper towels in the nest boxes—to remove the sticky eggs with as little disturbance as possible. Should a moth lay its tiny treasures on a cocoon, just snip them off and place ’em with the other eggs dropped (you hope) on the paper. Then, let the new seed dry for a few days before you store it.
Following mating and reproduction, both sexes of moth will die within a few days, bringing the silkworm story full circle. Take the poppy-seed-like eggs and place them in a small (labeled) jar to be saved in the crisper compartment of your refrigerator for next year’s effort.
As a potential “worm rancher,” you’d probably like to know what kind of profit you can expect from your work. Well, in terms of money from the sale of thread, the rewards probably won’t amount to much unless you have groves of mulberry trees and a number of hands to help you out in spring and early summer. But, on the other hand, so little silk is produced in North America that the market is wide open, and there are other ways to turn your hobby into an income besides selling material!
Both Mary Stock and Marguerite Shimmin, for example, find themselves in great demand for sericulture lectures to schoolchildren, clubs, and craft groups. Marguerite is sometimes commissioned by museums to make repairs in old tapestries, and Mary tells us that her homegrown silk is snatched up by area weavers for around $35 a pound! So, despite the time and effort required to grow and harvest their silk crops, both of these women feel well rewarded for their labors.
In addition to any monetary gains, though, sericulture offers a rare opportunity to understand the workings of nature, and a chance to appreciate the time dedication involved in the miraculous transformation from “mulberry leaves satin.” For many folks, those will be reasons enough to give silkworm cultivation a try.
All Around the Mulberry Bush….
If you’re interested in pursuing the art of sericulture, but lack a source of mulberry leaves to feed your “livestock”, you can prepare to start your own silk farm next year by ordering some seedlings of the necessary tree now! The Gurney Seed and Nursery Company sells three- to four-foot-high, two-year-old trees for $5.55 apiece or $24.95 for five … while J.E. Miller Nurseries, Inc. offers four- to five-foot, two-year-old trees for $5.45 apiece, or two for $9.95.
In a previous post, I
wrote about the potential of feeding
silkworms to chickens.
But how do you raise them?
Although you can buy
commercial feed for silkworms, those who want to create a sustainable
system will first need to plant or track down a mulberry tree.
Silkworms don’t eat as adults, and the caterpillars live entirely on
fresh mulberry leaves, preferably white or black mulberries. I
haven’t found information on how many silkworms you can raise on the
leaves of one tree without damaging it, so I’ll have to report on that
after a season of experimentation. In the meantime, I’ve scoped
out a few additional sources to supplement my young Illinois
if I run short.
Your next step is to find a
source of silkworm eggs. There are several different varieties of
silkworms, but I’ve opted to buy so-called Peace Silkworms since the
adults of this variety are able to break free of their cocoons and
breed naturally. Many other varieties have been bred to optimize
silk-production and have such thick cocoons that the adults perish
inside. I’m going to try out Aurora Silk, where you can buy 200
silkworm eggs for $30 with free shipping.
Once your eggs arrive,
you can keep them in a ziplock bag in the fridge for up to a few months
to delay hatch. When your mulberry tree is well leafed out, take
the eggs out of the fridge and leave them at room temperature in a box
or on a tray. It should take about a week for your eggs to hatch,
and you’ll know they’re nearly there when you see dark rings forming on
the eggs. Just before the eggs hatch, layer some mulberry leaves
underneath for the caterpillars to eat, then put a clear lid with some
air holes on your tray to hold moisture in the leaves without
suffocating your insects.
Silkworms are voracious
eaters of mulberry leaves, with various sources recommending topping
off their feed once to three times per day. When you do so, be
sure to supply fresh mulberry leaves with no water on them — young
caterpillars, especially, can drown in drops of dew. Every other
day or so, clean out the old leaves (perhaps using mesh trays so that
the caterpillars can crawl up into the fresh leaves without your help).
Chickens are supposed to
like silkworms best when they’re less than two inches long, but the
insects will keep growing up to three inches. At that size, about
one month after hatching, the silkworms stop eating and
turn yellow — your cue that they’re ready to move on to the pupation
phase. Take out any remaining mulberry leaves and place the
bottom half of a egg carton in the silkworm habitat, providing about
one egg cup per caterpillar. It’s best to try to save at least
twenty caterpillars to reach this stage if you want to keep the cycle
Within three days, the
silkworms should have spun cocoons, and three weeks later they will
emerge as flight-less moths. Provide paper towels or another type
of bedding and the female moths will mate and then lay 200 to 500 eggs
apiece. If you want to raise another batch right away, just put
the eggs in a container and wait for them to hatch in a week, or move
them to the fridge to store until the mulberry leaves are flush again.
The Avian Aqua Miser is an automatic chicken
waterer that makes chicken care so easy you have time to raise
silk making step 1: raising silkworms and harvesting cocoons
silkworms are really not worms at all. silk worms are the larvae of ‘bombyx mori’ moths and silkworms are actually domesticated insects. native to china, the silkworm does not longer exist in the wild, after so many centuries of inbreeding the silkworm is incapable of flight, mates quickly after emerging from its crysalis, and dies a day or so after laying its eggs.
designboom illustrates the several stages of sericulture, which begins with hatching silkworm eggs …
image © designboom
at the beginning every few days, the worms need to be moved to a clean tray with fresh food. members of the farmer’s household must spend a growing amount of time to their bamboo trays, also because silkworms produce quite a lot of excrement and cleaning the trays is not a job for the weak-stomached. they continue feeding and moving the silkworms, dividing the colonies when the silkworms are too large or hungry for the numbers in that tray. by the fourth week, the largest of the silkworms will be more than 5 cm. long, fat, and hungry enough that they need to be fed every day.
an easy test confirms their readiness to cocooning. the farmer picks them up and looks between their rear pair of legs, from the underside. if there is a gray mass there, the caterpillar isn’t quite ready, but if it’s milky and translucent, the silkworm has pooped its last and is definitely ready. the worms suddenly stop eating and raise their heads – another sign that they are ready for the all-important job of spinning cocoons.
image © designboom
the ‘bombyx mori’ worms are now inserted in a specially woven circular bamboo scaffolding, which will make the cocoons more uniform in shape and easier to collect.
each silkworm now doubles itself up on its back, and by contracting secretes, from an opening under its mouth, a steady stream of liquid silk, coated with sericin, which hardens on exposure to air. they’re starting to lay out the support strands for their cocoons, although they may not yet be serious about cocooning.
at that stage they are removed from their feeding trays.
image © designboom
some of the larger caterpillars are climbing the walls of the tray (they’ve done this before, to shed their skins, but this time their heads are pointing toward the lid) and the busy silkworms are guided by figure of eight movements of their heads, to dispose the liquid silk in layers, forming the cocoon. after some 36 hours, the worms are sealed within a yellow cocoon, embarked on the process of metamorphosing into a moth.
General Information, Caring For & Breeding Silkworms
| Silkworms are the larva of a moth (Bombyx mori) native to Asia that spins a cocoon of fine, strong, lustrous fiber that is the source of commercial silk. The culture of silkworms is called sericulture. The various species raised today are distinguished by the quality of the silk they produce. Silkworms feed on the leaves of the mulberries (genus Morus) and sometimes on the Osage orange (Maclura pomifera).
Bombyx Mori will not bite, making it an ideal worm for feeding most reptiles, amphibians and other animals. And they offer great nutritional value as a live feeder.
Newborns are small enough for most baby reptiles to eat and young silkworms can even be fed so they will grow to a desired size. Silkworms are soft-bodied, slow moving and can grow to 3 inches in length. They are also relatively fast growing, reaching about 3 inches in length and ready to cocoon in as little as 25 – 28 days.
Silkworm and Cocoon
Today, the silkworm moth lives only in captivity. Silkworms have been domesticated so that they can no longer survive independently in nature,
particularly since they have lost the ability to fly. All wild populations are extinct. Also contributing to their extinction is the extraordinary fact that they only eat mulberry leaves.
Silkworms have been used by researchers to study pheromones or sexual attractant substances. The pheromones are released by female moths and the males detect the chemicals with olfactory hairs on their antennae. This allows the male to find the female for mating. The male antennae are made of many small hairs to increase the chances of picking up small amounts of the pheromones over long distances.
How to Grow Your Worms to the Perfect Size
Silkworm Eggs and Moth
|The great thing about silkworms is that they only grow as much as you feed them, and they can go for up to a week without food. Keep in mind, however, that they will become dehydrated and begin to die off after a few days without food, and should be fed at least once daily in order to remain healthy. But, in general, if you have too many you can feed them a few times per week and they’ll stay alive until you need them without growing too much larger.|
| Wash hands thoroughly before handling the worms or the food or they may develop bacterial problems. Using a cheese grater, grate a small amount of food onto the them and repeat until the caterpillars reach the desired size. For best results, maintain temperatures between 78° and 88° F.
Excessive condensation forming in the container after feeding is the leading cause of failure. If this condensation does form, take the lid off your container and allow the container and old food to completely dry out. In the future, make sure the previous food is dry before feeding again. Old damp food is a breeding ground for mold and other problems, dry food is not. A fan can help for quicker dry outs.
Newly hatched silkworms are tiny
As the silkworms grow, you may need to transfer your worms to a larger plastic container. The lid needs to have ventilation holes. If not, you need to vent the lid so the silkworms won’t suffocate and to allow condensation to dissipate. You can also use a shoebox. The old food and waste matter can be removed, but does not have to be if it remains thoroughly dry.
Under ideal conditions (78° to 88° F and allowed to feed nearly continuously) silkworms can go from egg to 1 inch in length in about 12 days, and 3 inches in under 30 days. The worms will begin to spin cocoons at about 28 – 30 days old or when they are between 2 1/2 and 3 inches long.
For more detailed silkworm care instruction, please see our FAQ page.
From Cocoon to Moth
|Silkworm moths emerge from their cocoons after spending about two to three weeks metamorphosing. As moths, they do not eat or fly. They will usually mate, lay eggs and die within a week. Fertile eggs turn from yellow to gray or purple in a week or so. If the eggs don’t hatch within 3 weeks, they usually will not hatch until the following year (see above—from egg to larva).|
Proper Handling Procedures
Again, in order for your worms to stay healthy for many weeks, you’ll need to keep the silkworms as dry as possible. If condensation builds up during feeding, vent the container lid to prevent excess humidity.
Be sure to wash your hands thoroughly before handling the worms or their food. Silkworms can be susceptible to bacteria if you don’t properly handle them. As long as the container environment remains dry, your worms will be fine.
Mold develops from high temperatures and high humidity. If the worms are covered with droppings, silk and old food for too long, mold may develop and kill the worms. If mold does develop, grate about 1/4 inch of food (sold separately) all over the worms with a cheese grater. As the worms crawl to the top of the new food pile you can transfer them off the moldy food and place them into a new container.
Silkworms are susceptible to bruising and dying if not handled with care, especially as they grow larger.
When handling and transferring the worms, be very gentle.
For more information about caring for this amazing creature, see our Frequently Asked Questions. You may also want to visit our page about the numerous benefits that it offers HERE.
If you would like to purchase silkworms, Please visit our SHOP HERE.
Wikipedia.org – As always, this website is a wonderful place to find information on just about anything.
Sue Kayton’s Website is a good source for K-12 teachers who want to raise silkworms in their classroom.
The Culture of the Mulberry Silkworm is a free ebook available on Google. It is from the U.S. Department of Agriculture and provides a wealth of information about caring for and rearing silkworms.
ASOS, the popular and rapidly growing British online fashion retailer, has announced a major new change in the products it will—or rather won’t—carry.
Under pressure from the animal-welfare group PETA, the company has joined the likes of Zara, H&M, Gap, and others in ditching mohair, but it’s also going a few steps further. The company’s new policy will ban products using cashmere, silk, feathers (including down), bone, horn, shell (including mother of pearl), and teeth from ASOS’s websites too. It will be fully in effect by the end of January 2019.
But one banned material in the list has caused some to pause: Silk, which is made by silkworms.
“They’re insects,” said one shopper interviewed on a high street by the BBC. Thomas, 33, told the BBC he was “delighted” by ASOS’s other bans—”anything that discourages the hurting or harming of any animal is good”—but was confused by the concern for silkworms. “I think sentient animals definitely, but things like worms—it’s not going to be such a big deal, is it?”
The logic of ASOS’s choice to cease using most of these animal-derived materials is evident. There are awful stories about animal abuse in the farming of mohair and feathers. The boom of the cashmere industry has had serious environmental consequences (pdf). Bone, horn, and teeth, which are typically used for things like buttons, often require a mammal dying. (ASOS, incidentally, already did not sell real fur, and says it will only use leather that is a byproduct of the meat industry and wool from suppliers with good animal husbandry.)
But why silk? And should this be the next product that a conscious consumer must give up?
As with almost anything we wear, buy, or eat, the ethics of wearing or eschewing silk aren’t entirely straightforward, and a person’s decision ultimately comes down to what factors matter most to them. Here are some considerations to keep in mind when making your own decision:
How is silk made?
There’s no getting around this: Silkworms die to produce silk.
There are different types of silk, but the variety we generally refer to when we talk about silk—the one used for stunning saris or flowy dresses—comes from the mulberry silkworm, Bombyx mori. It isn’t actually a worm; it’s a mulberry-leaf-munching moth pupa. It spins silk to make the cocoon for its transformation into its adult form as a winged moth.
Reuters/Alessandro Bianchi A silkworm, which isn’t really a worm at all, tucks into some mulberry leaves.
That silken cocoon is what silk producers are after, and they want it intact. Once the worm has spun it, but before it’s able to break out and damage it, silk producers will treat the cocoon with hot air, steam, or boiling water, in a process called “stifling.” In sunny, tropical areas, it might also be done by placing the cocoons in bright sunshine. These processes make the cocoon easier to unwind in a single, unbroken filament that can be woven into silk thread.
But when you dip the cocoon in boiling water or bake it with hot air, you’re killing the pupa inside. And huge amounts of pupa are killed in these ways to make the world’s silk. To make one pound of the lustrous, revered material requires about 2,500 or more silkworms.
There is a variety of silk called Peace Silk, or Ahimsa Silk, that doesn’t involve stifling. But animal-welfare advocates, including PETA, are skeptical of how humane this method is. There’s no certification to make sure the process meets standards. One group in India reported female moths being stored in trays to lay eggs at one facility, while the males were “put into the refrigerator and kept in a semi-frozen condition” until they were brought out to mate. Once they could no longer mate, they were discarded.
Can silkworms feel pain?
If you set your ethical bar at whether a living thing died to produce a product, then silk is a fiber you’ll want to avoid.
But for many, like the man the BBC spoke with, the question is whether the living thing involved has the level of consciousness required to experience pain.
Yes, silkworms are cooked in their cocoons, but do they suffer? PETA believes so. “Although worms can’t show their distress in ways that humans easily recognise, anyone who has ever seen earthworms become startled when their dark homes are uncovered must acknowledge that worms are sensitive,” it says. “They produce endorphins and have a physical response to pain.”
The science isn’t so clear though. The release of endorphins, which happens in many animals, including humans, modifies the senses and helps us cope with pain. Earthworms have been found to produce endorphins, which does suggest a response of some sort to pain. But again, silkworms aren’t actually worms, so the earthworm example may not be a particularly useful indicator.
“So, what do these insects feel, if anything?” asked the animal-rights advocate Mark Hawthorne, in his 2013 book, Bleating Hearts: The Hidden World of Animal Suffering. “I put the question to Thomas Miller, an entomologist at the University of California—Riverside, who says that silkworms have a central nervous system, but that they lack structures equivalent to vertebrate pain receptors. ‘Bottom line,’ he says, ‘there is no evidence they experience what you call pain.’” (Hawthorne was skeptical of the answer because, he notes, scientists will occasionally come to one conclusion only to reverse it later as more evidence comes to light.)
Reuters/Alessandro Bianchi You could say they’re like a black box.
Some research indicates that invertebrates don’t experience pain as we understand it. But we aren’t able to determine exactly what they experience.
Last year, Gizmodo asked a group of neuroscientists, biologists, and entomologists what we understand about the way insects sense and experience the world. The general consensus was that, while they may recoil from harmful stimuli, they almost certainly don’t “feel” things the same way we do, and we can’t definitively say what they experience, including whether they feel pain.
The reality is that, right now, we don’t really have a clear answer on whether silkworms feel what we call pain.
What about silk’s costs and benefits to humans?
Silk’s detractors will point to the awful incidents of child labor found in the silk industry in India and Uzbekistan.
But sericulture, or the production of silk and rearing of silkworms, has also been an important part of certain cultures for centuries, especially in India and China, the world’s biggest silk producers. In both countries today it still provides livelihoods to a large number of people.
Reuters/Stringer A silk producer in Sihong county, Jiangsu province, China.
In rural areas of India, in particular, the work it offers can be invaluable, especially for women. “The sericulture industry has opened up phenomenal employment avenues and helped women to become important players in the decision-making process—whether in the household or in the community at large,” wrote the author of one study of a South Indian village. Another concluded (pdf) that the work women found in sericulture had positive spillover effects on education and nutrition in their households.
If you’re buying silk from a big brand, however, it’s probably coming from an industrial facility in China. Often brands themselves aren’t even sure where their materials originate.
What are the alternatives to silk?
If you decide you’d rather not wear silk, there are man-made alternatives you might consider as substitutes. Unfortunately these may not be any better, ethically speaking.
The main one is rayon, also called viscose, the first-ever man-made fiber. It was developed as a silk substitute in the late 19th century, and is made of regenerated and purified cellulose, usually derived from wood pulp. Despite its main ingredient being plant-based, the process to manufacture it requires highly toxic chemicals. Last year, a report linked H&M, Zara, and Marks & Spencer to viscose factories in China, India, and Indonesia that were causing severe environmental pollution and harming the health of nearby communities.
You could also consider some varieties of polyester, but polyester has been found to leech tiny plastic fibers when washed that end up in waterways, and ultimately, in fish. Microfiber pollution is now recognized as a serious and still growing problem. Even cotton, a thirsty crop and a material that is very hard to recycle, doesn’t come entirely guilt-free.
So, is it ethical to wear silk? By now it’s probably evident that there’s no one clear answer. It depends on your own personal values and priorities and how you weigh them against one another.
It’s worth remembering, though, that just about any product comes with its own set of ethical tradeoffs. As Clare Press wrote in Vogue of the materials that ASOS banned, “Everything comes with a cost of some sort.”
12.2.6 Non-infectious Biotic Agents
Silkworms can suffer from injuries caused by non-infectious biotic agents such as parasitoids, parasitic mites, and urticating hairs of other Lepidoptera.
Silkworm larvae are attacked by tachinid parasitoids (called uji flies), mainly in the genus Exorista spp. (E. sorbillans and E. bombycis), but also including Crossococmia sericariae, Ctenophorocera pavida, and Blepharipa zebina. These uji flies can threaten the sericultural industry and are most serious during the summer. Losses due to tachinids can reach 10–15% in China, and exceed 30% in areas of southern China that are hot and humid (Jin, 2001). Exorista sorbillans typically produces four to five generations in northern and north-eastern China, six to seven generations in eastern China, and 10–14 generations in southern China. Both males and females mate multiple times before females start laying eggs, usually on the second day after sufficient mating events have occurred. Exorista sorbillans uses odor to locate hosts, laying eggs on fifth instar silkworm larvae. Larvae require only four to five days to mature, with the pupal stage lasting 10–12 days or for several months if the pupae go into winter diapause. Exorista sorbillans is a generalist parasitoid with a host range that includes more than 10 other species of Lepidoptera (Jin, 2001).
The first sign of attack is a small brown lesion, where the parasitoid larva penetrated through the cuticle into the hemocoel. The eggshell of the parasitoid can sometimes be seen on the lesion, but normally it drops off the host’s cuticle. The lesion enlarges over time, becoming a black–brown, horn-shaped sheath as the silkworm larva grows. The yellowish parasitoid larva can be found if the lesion is dissected. The silkworms sometimes take on a purplish color, due to oxidized hemolymph, and larvae often cannot complete development to the adult stage and often do not even pupate. Parasitoids pupate outside the host.
More than 10 species of mite in various families are known to parasitize silkworm larvae, pupae, and adults. Among them, the straw itch mite Pyemotes ventricosus is the most common. It reproduces ovovivipariously (i.e., eggs, larvae, and nymphs develop inside the maternal body), leading to the emergence of adult mites. The mites are yellow with a large, globose abdomen, and visible without magnification. Newly emerged adult females mate immediately and actively search for hosts, which they pierce with their needle-shaped chelicerae, injecting a toxin that paralyzes the silkworm. The mites continue to feed on the hemolymph until the host dies. Pyemotes ventricosus produces several generations per year, and as many as 17–18 generations can occur in eastern China. Winter diapause occurs in the mated females. Another host of P. ventricosus is the pink bollworm, Pectinophora gossypiella, and therefore, silkworm infestations can be more serious in cotton-producing areas where the rearing rooms are also used for storing cotton.
When early instar silkworms are parasitized, the larvae stop feeding and often experience spasms and vomiting. When the larvae die, the body is typically curved, with the head protruded and the thorax swollen. First and second instar silkworms are usually killed in less than 10 h. Third instar silkworms develop asynchronously and become grayish yellow and shrunken. The larvae then become slightly reddish and swollen, especially the posterior segments, and a reddish brown effluent is defecated. The larvae die hanging upside-down.
The mature larvae are rarely infested, but when attacked, they shrink and exhibit a prolapsed anus. The posterior segments produce a black–brown or red–brown effluent, and spots appear on the thorax and abdomen. These infested larvae usually die just before molting, or during molting, with symptoms similar to those in the younger larvae. Pupae are usually parasitized in the intersegmental membranes on the dorsal side of the abdomen. Infested pupae also develop a large number of black spots and die before emergence. The cadavers are black–brown and show no signs of decay. Adult moths do not show any obvious symptoms when infested. The female mite usually parasitizes adult silkworms on the intersegmental membranes of the abdomen, and the moths become less flexible. Infested males do not behave normally, and the infested females lay fewer eggs, many of which are not viable (Jin, 2001).
The mulberry tussock moth, Euproctis similis, has urticating hairs that can poison silkworm larvae. The moth is a common pest on mulberry plantations, producing up to three generations, and overwinters as larvae. Larvae have needle-shaped, aggregate setae that secrete formic acid and toxic proteins. Stings from these setae can occur on silkworms throughout the year. Young silkworm larvae and newly molted larvae are affected the most, exhibiting tissue necrosis from the poisonous setae. Brown or black–brown spots appear first on the abdomen, extend gradually to the prolegs, and finally aggregate in large numbers along the intersegmental membranes, resulting in an irregular belt of black spots or black feet if the spots aggregate on the prolegs. The toxins can also enter the hemocoel, affecting other tissues and organs. Physiological effects include retarded development and delayed molts, and in some cases, death of small larvae. Some poorly developed larvae can spin cocoons and pupate, but the quality of the silk is low.
Consumption of mulberry leaves contaminated with these poisonous setae results in damage to the epithelial cells of the foregut, extending to the posterior part of the midgut. As a result, the silkworm larvae reduce their feeding rate and develop slowly into small-sized larvae. Larvae that have consumed a large number of setae stop feeding entirely, then swing their head from side to side, vomiting, and eventually die. If first instars feed on mulberry leaves contaminated with setae, they die very quickly.
Various slug caterpillars (Limacodidae), such as the mulberry slug caterpillar, Thosea postornata, are pests of mulberries. The slug caterpillar has a broad food preference and usually produces two generations per year, with mature larvae overwintering inside their cocoons. The larvae pupate the following spring. The moths emerge and lay eggs that hatch in early July. The larvae have tufted stinging hairs that are long and stiff and secrete acidic toxins. The stinging hairs damage the integument of silkworm larvae, but the toxins can also enter the hemolymph. Damaged silkworm integument will bleed small amounts of hemolymph, which coagulates into small black–brown round spots. These spots are larger than those caused by mulberry tussock moths. When exposure to the urticating hairs is light, the silkworm larvae stop feeding for 30–60 min before gradually resuming their feeding, but larval development will be retarded. Heavy exposure will cause the silkworms to die within a few hours to a couple of days. The cadavers become flaccid and black (Jin, 2001).
Silkworm moth, (Bombyx mori), lepidopteran whose caterpillar has been used in silk production (sericulture) for thousands of years. Although native to China, the silkworm has been introduced throughout the world and has undergone complete domestication, with the species no longer being found in the wild.
An adult silkworm has a wingspan of 40 to 50 mm (about 2 inches) and has a thick bristly body (the adult female is larger than the adult male). It typically is blond to light brown in colour, with thin dark bands running across the body. The wings are cream-coloured and have dark veins extending out to the margins. Mouthparts in adults are reduced or absent, so in their brief adulthood of two or three days, they do not eat. They cannot fly, either. Males, however, perform a flutter dance, a mating ritual induced by females’ secretion of a pheromone known as bombykol. Females lay about 300 to 500 eggs, which hatch within roughly 7 to 14 days when kept at temperatures of 24 to 29 °C (about 75 to 85 °F).
silkworm mothSilkworm moths (Bombyx mori) mating on cocoons.Stephen Dalton—NHPA/Encyclopædia Britannica, Inc.bionics: silkworm moths and butterfliesBionics researchers studying silkworm moths and butterflies.Contunico © ZDF Enterprises GmbH, MainzSee all videos for this article
Newly hatched larvae are approximately 2 to 3 mm (0.08 to 0.12 inch) long and have voracious appetites. Besides its natural food of mulberry leaves, silkworm caterpillars also eat the foliage of the Osage orange or lettuce. The pale larva has a characteristic posterior (caudal) horn. It attains a maximum length of 75 mm (about 3 inches) during a 45-day growing period. Pupation occurs within a cocoon that is made of one continuous white or yellow strand of silk averaging about 915 metres (1,000 yards) long. This filament is preserved intact for commercial use by killing the pupa with hot air or steam. Silkworms whose genomes have been genetically modified through the introduction of spider silk genes produce silk that is stronger, tougher, and more elastic than that produced by domesticated silkworms.
The silkworm moth is in the family Bombycidae, and its closest relative is the wild silk moth (B. mandarina). Related moth families include Saturniidae, Apatelodidae, Oxytenidae, Carthaeidae, and Lemoniidae.
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PRODUCT AVAILABILITY – Updated 1/9/2020:
◊ Current Silkworm Stock:
Extra Small, Small and Medium Silkies now in stock!
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The Many Uses for the Silkworm:
➀ LIVE FEEDER
Silkworms are PACKED with nutrition and low in fat, making them about the best feeder you can give your pet. Silkworms are for a HUGE variety of reptiles, amphibians, birds and fish. They are soft-bodied and easy to swallow and digest, making them a perfect choice for sick animals or finicky eaters. The extremely high calcium content makes them ideal for gravid egg laying animals and improves bone health in all animals. Silkworm are easy to care for and have no odor. You will find much more information on the benefits and general background of this caterpillar HERE.
We have SILKWORMS FOR SALE HERE.
➁ CLASSROOM LEARNING
Silkworms are used by educators all over the country for teaching about biological life-cycles, entomology and also hands-on history lessons about China and silk. If you are an educator of any kind, you will definitely want to spend time in our TEACHER RESOURCES SECTION. We think you’ll agree that a SILKWORM PROJECT is the perfect immersive lesson plan. You’ll also find our ideas for classroom activities and observations as well as lessons for the silkworm lab.
➂ARTS & CRAFTS
Many folks use the whole cocoon or the unwound silk fiber from the silkworm moth cocoon for craft projects. You can either grow your own or may want to purchase our whole cocoons. SHOP HERE.
Universities and other organizations order from us regularly. Female silkworm moths attract male mates with the pheromone bombykol, a volatile 16-carbon alcohol that is widely studied. As is the male moth’s pheromone-binding protein in its antennae. The amazing properties of the silk and silk producing gland are also actively studied in a quest to find new ground breaking fibers of incredible strength. What else they are doing, we are not sure.
➄ JUST FOR FUN
Lots of people enjoy keeping and growing the silkworms as a pet. They are cute, fun to hold and fascinating to watch go from egg to tiny caterpillar and grow so fast into a jumbo white caterpillar which then spins a cocoon only to have an adorable furry white moth emerge. Speaking of fun, you may also be interested in singing a little SILKWORM SONG, reciting a SILKWORM POEM and telling a SILKWORM JOKE.
Silkworm Care Sheet
A silkworm starts its life as a tiny egg laid by the female moth. The egg is just about this size: . The egg, laid in the summer or early Spring, remains dormant until the warmth of spring stimulates it to start developing. When silkworms first hatch in the spring, they are tiny—3 mm or so (about 1/8″)—and hairy. They require young tender mulberry leaves during their first few days. As they grow, they can eat tougher leaves, and late in their development they will eat any mulberry leaf you can supply.
The larvae advance through five stages of growth, called instars. The silkworm literally outgrows its skin five times, and moults its outgrown skin. With the first moult the silkworm loses its hairy exterior, and for the rest of its larval life its skin is soft and smooth.
Silkworms grow rapidly, eventually reaching the size of your ring finger. Then they spin beautiful oval white or yellow cocoons in which they pupate. After 2–3 weeks the creamy-white adult moths emerge from the cocoons. They clamber around, vibrate their wings rapidly, and mate, but they don’t fly or attempt to escape from their container. During the adult phase of the life cycle, the silkworm moths do not eat or drink. After mating, the female lays a profusion of eggs, and the moths die.
Males and females look slightly different, and students will be able to tell them apart with a little practice. The female has a larger abdomen. The male has a much larger pair of antennae, which look like long rakes or comb-shaped eyebrows, and vibrates its wings rapidly to attract a female.
Silkworm Feeding Silkworms eat mulberry leaves; lots of them! But getting leaves in late spring and winter months is nearly impossible, as the trees are deciduous.
The silkworm eggs must hatch when mulberry leaves and catkins (flowering portion of the mulberry tree) are available. If you are not sure when mulberry trees begin budding in your area, ask a neighbour or enquire at a nursery. We now also sell Mulberry Silkworm Chow which is another food source for your Silkworms.
Habitat. A shoe box is all that you need to make a silkworm habitat. Choose a place in the room where the silkworms will be warm but not in direct sunlight. Place the shoe box in an open plastic bag, or drape a sheet of plastic over the box. The idea is to reduce evaporation from the leaves a bit without developing a humid environment.
If the eggs are scattered all over the box, that is OK, but the larvae should be placed on a leaf. New larvae must be rounded up each day and delivered to a fresh mulberry leaf.
Larva. Silkworm larva are delicate at first and should not be handled for the first 2 weeks except with a tiny paintbrush. By the time the larvae are 2 cm (1″) long, students can carefully pick up and gently hold them. The larvae seem to survive better if they are kept together in a single culture early in life—later they can be kept in pairs or small groups on students’ desks.
Plan for spinning. Get a medium-size corrugated cardboard box and a couple of paper egg cartons. Open the egg cartons and attach them to the inside walls of the box. The silkworms will spin in the depressions in the egg cartons. The silkworms must all be in this box for spinning their cocoons. The time for this will be signalled by the first larva that starts to spin, either in your class habitat or, more likely, in one of the group habitats.
Prepare for silkworm moths. Once the larvae spin cocoons, they require no further care. The moths will emerge in a couple of weeks and can be handled by students. They do not eat or drink—they mate, lay eggs, and die.
Prepare for mating and egg laying. Get a large flat box, or cut a taller one down to about 10 cm (4″). Line the bottom with paper. As the adults emerge, move them to this new box. The moths will stay in the open box. The females will lay eggs on the paper, making them easy to collect.
Collect eggs. The eggs will remain viable for a year with minimal care. Seal them in a labelled zip bag and put them in the refrigerator (not the freezer!) as soon as all the moths have died. If you don’t refrigerate the eggs, they will still hatch, but over an extended period of time instead of all at once.
Did you know you can grow your own silk from your own silkworms? Well you can! Add silkworms to your backyard farm as a source of income, a child’s science project, or anything in between. Silkworms eat mulberry leaves, and they do not leave their food source. They can be reared in open boxes with your own homegrown leaves if you have enough mulberry trees.
Why Raise Silkworms?
In commercial silk operations frequently the worms are killed. Often the worms are fed hormones and growth hormones which are then present within the finished silk. Also often times silk is imported from out of the country. If you are trying to live a more sustainable, local lifestyle producing your own fibers is an admirable goal. How fun it would be to do your own knitting or crocheting from fibers you grew and produced yourself! Silk is also currently endangered, so even keeping them as a hobby can help preserve the species.
Peace silk is produced by letting the moths naturally emerge from their cocoons, breed, and lay eggs, unlike some commercial silk, where the silkworms are killed before they emerge. Instead, they are allowed to emerge from their cocoons, mate, and die happy. The alternative is to bake the pupa before they emerge from the cocoons. Then instead of spinning the fibers you can unreel them in one long strand. If you choose the later method, the cooked pupa could be fed to your chickens as a homegrown snack.
Raising silkworms could also provide a bit of income. You could sell the eggs to other potential raisers, or as an education tool to classrooms and homeschoolers. You could raise the worms to be used as a high protein reptile or chicken feed. The silk could be sold raw, or even made into homemade items for purchase. Operating expenses should be low if you are raising all your own mulberry plants.
How To Get Started
The first step in caring for silkworms is to make sure you have a feed source. Silkworms eat mulberry leaves, and only mulberry leaves. If you have a mulberry tree or a couple of bushes you should be able to feed about 25 worms per year. You should be able to find them at a local nursery or even on Amazon. Goats and rabbits can safely eat mulberry leaves. Chickens will happily clean up any fallen fruit that you don’t harvest for yourself. Mulberry plants are also good partners for apple trees if you set up a plant guild. They can be coppiced and used for firewood. Mulberry bushes can also make good hedges, so it shouldn’t be hard to add in such multi-purpose plants even in a small scale homestead.
You can purchase silkworm eggs online from Aurora Silk. They are also available online from Silkworm Shop. You may need to invest in a moderate amount of equipment. such as shelves with trays for them to grow on, thermometers and space heaters to maintain ideal temperatures, but it’s possible you may be able to repurpose things you already have into workable solutions. Cardboard boxes should work for hatching chambers. Rubbermaid tubs may make good growing chambers. You could use an aquarium and rolled paper to create a spinning chamber.
Caring For Silkworms
When you first receive silkworm eggs you should keep them at about 80 degrees for seven to fourteen days. They should have about six square inches per 25 worms. As soon as they hatch they will need shredded tender mulberry leaves two or three times per day. They should be kept at a consistent temperature, although some sources say 70-72 degrees and others say 75-85 degrees.
As the worms grow they can handle more mature leaves, and should be fed three to four times a day. Mature worms should be given two square feet per twenty five worms. Their waste should be cleaned frequently. Loosely woven baskets that let the waste fall through should make it an easier job. The silkworms will molt periodically. During a molt they will not eat or move much.
Before the worms begin to spin they should be placed in a spinning chamber with ample space and ventilation. Brushy twigs or bundles of straw make good places for them to spin their cocoons. After this stage you can either steam the chrysalises to kill the pupa or you can let them all hatch. Make sure to separate your breeders if choosing the first method.
The mature moths emerge, mate, lay eggs and then die. They do not eat or fly. The females should be given leaves to lay their eggs on so that you can remove the eggs and place them in the refrigerator. They require a three month cooling period before they will hatch and be ready to begin the cycle again.
If you think silkworms might be a good fit for your homestead there are a few sources with detailed information on cultivating silkworms. The I Like Bugs article is a quick read with detailed instructions on raising silkworms. Google Books has a free copy of The Culture Of The Mulberry Silkworm, published by the U.S. Department of Agriculture in 1903. It’s old, but it’s very meticulous in it’s detail.
By utilizing the resources you can produce in a small space and with homegrown feeds, you can increase the productivity and usefulness of your homestead. Silkworms could absolutely make your homestead better!
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