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School Tours
If you are looking for an educating, enriching school exursion, discover the intricacies of silk worm farming at the Bombyx Silk Worm Farm. Understand the histing of silk, its properties and benefits on a silk worm farming school tour.
History
The history of the silk worms, which is the history of silk, goes back to ancient times in China. Some stories have been handed down through generations and are probably based partly on fact and partly on legend and myth.
The tale which persists is the one dating back to about 2640 B.C. A Chinese Empress, Si-Ling-Chi, was watching the glistening pearl cocoons that the worms where spinning in the mulberry trees in the palace gardens. One dropped out the tree and landed in her cup of tea. As she scooped up the cocoon the threads pulled away revealing one, very long strand of fiber. Fascinated, she pulled strands from several other cocoons through her ring to form a thicker thread. Eventually, with the help of the ladies of her court, she spun these threads into a beautiful piece of cloth. This was made into a robe for the Emperor, Huang-Ti. This magnificent material, SILK, became known as the “Cloth of Kings”
For thousands of years the royal family of China had silk. The Chinese kept the secret of how silk was made for 2500 years. The material was sold to the rulers of the west, however the source of the shiny thread that made the material was not revealed. The penalty of revealing the secret was death.
Some very strange ideas were formulated as to the origin of the silk. For example, silk was made from wondrously soft soil; silk came from a spider-like animal that ate until it burst open releasing the silk that was inside its body; it grew on a tree and could be plucked like cotton.
Legend has it that the Japanese carried off four Chinese maidens, who knew the secret of silk, along with the mulberry shoots and silk moths eggs. Today Japan is a leading producer of silk.
When a Chinese Princess was sent off to marry an Indian Prince, she carried silkworms and mulberry shoots in her elaborate headdress. So, with the secret of raising silkworms in her head, she spread the culture of silk to India.
Silk was still only privy to those in the East. Finally, around 550AD, two poor monks told Emperor Justinian of Constantinople that they have to learn the secret of silk. Justinian sent them to China to get some eggs and mulberry shoots for him. They returned many years later, at great risk to their lives, with the eggs and shoots hidden inside their hollowed-out walking sticks. Since Justinian was the Emperor of Constantinople, the secret soon spread through out Byzantine and eventually, Europe.
Still to this day – the secret of silk has been the longest kept secret in history!
Types of Silkworms
There are three different types of silkworms, namely Univoltine, Bivoltine and Multivoltine.
The Univoltine silkworm is the common South African silkworm. It spins a soft yellowish colour cocoon, in a small oval shape. The worm itself is very tough - Making it easy to handle and ideal for kids. The Univoltine is named after how many times they spin a year. –UNI- means one. So the Univoltine silk worm spins only once a year. Usually in spring time.
The Bivoltine silkworm is just the opposite of the Univoltine silk worm. Not indigenous to South Africa. It spins a large, hard white cocoon. The worm is unbelievably sensitive. They are so sensitive to smells and odors that a person with strong perfume can kill a whole rack of silk worms. The Bivoltine Silkworm is also the silkworm with the best quality silk. –BI- means two, so the Bivoltine will spin twice a year. The silk used by us is from the Bivoltine silkworm, as this is the best quality silk available.
The Multivoltine Silkworm also spins a yellowish colour cocoon. Just a little bigger than the Univoltine cocoon. Not indigenous to South Africa. It’s mostly farmed in India, and is also a tough worm. –MULTI- means three and more. The Multivoltine silk worm spins right throughout the year.
Feeding
A silk worm eats mulberry leaves. We only use two different moruses, better known as mulberry trees. The morus Australis – Variety: Noi and the morus Acidosa – Variety: Waterkloof. If ideal climate conditions exist, the Noi mulberry tree is evergreen and will have leaves throughout the year. This tree grows small leaves and flowers.
The Waterkloof, on the other hand grows a large leaf and bears the mulberry fruit. If the mulberry trees are left to grow unattended, then they will grow into large trees. We keep the trees small like a scrub. The smaller the trees, the softer the leaves. The mulberry leaves are very high in protein.
The eggs are kept in a tray, covered with a net with holes just big enough so that the worms can fit trough. The freshly chopped leaves are placed on top. The worms will climb trough the net to the fresh leaves. Every four hours the worms are fed. After each fourth hour another net is placed on top of the old leaves, with the new fresh leaves on top of the net. In this way the worms keep climbing through the net to the new leaves, allowing the old leaves to be cleaned away.
The Cycle of the Silk Worm
A silk worm lives for 23 – 28 days. During these 28 days, the silk worm will go through 5 stages:
The First Stage
After ten days the eggs will hatch and enter into the 1st stage. They will eat for 3 days and 3 nights continuously without any sleeping. They are called the Brown Hairy Worm or the Ant worm. In this stage they are about 3mm long.
We’ll then cut the leaves smaller ( about 3mm ) so that it is easier for the baby worms to eat. After their first stage they will go into their first resting period.
Resting Period
They will rest for 24 hours ( 1day ) to grow and then shed their skin. They lie with their bodies flat and their heads upright. The higher their heads are the deeper in sleep they are. In china they play classical music to their silk worms in order to get a better quality silk. We are not sure what the success of this method is, however it is used in some areas. This resting period will take place between each stage. A total of 4 times.
The Second Stage
In their 2nd stage they will again eat for 3 days and 3 nights continuously without any sleep. And again go into their resting period.
The Third Stage
In their 3rd stage they will eat for 4 days and 4 nights continuously without any sleeping. And again they will go into their resting period.
The Fourth Stage
In their 4th stage they will eat for 6 days and 6 nights continuously without any sleeping. And again they will go into their resting period for the last time.
Fifth and Final Stage
In their 5th and final stage they will eat for 8 days and 8 nights continuously without any sleep. They’ve multiplied their weight 10 000 times - From a 3mm worm up to a 6 – 8cm worm.
Each worm will eat about 80 grams of mulberry leaves. In this stage 50% of its body is pure silk. The rest is the 2 silk glands and other organs.
After this stage they will start spinning their cocoons.
Spinning Cocoons
They will perform a total of 150 000 head movements for 3 days and 3 nights to spin 1 cocoon, without any sleep and food. If a person unwinds a cocoon, the thread can vary in length from 850 meters to 1800 meters. Making Silk the longest natural fiber.
After the worm has spun its cocoon, it will start turning into a pupa. While it’s turning into a pupa, it will shed its skin for the last time. The pupa then remains in the cocoon for a period of 10 days.
Mating Period
The natural process of mating takes place when the moths are left to nature. The male moth hatches from the cocoon first and it will rapidly move around searching for the female moth. The female moth only hatches 2 days after the male. The male will waste its energy searching for the female. 2 days later the female moth will hatch. The male and female moth will then mate. After mating, the male moth dies. The female moth will then lay her eggs. After laying her eggs she will urinate on top of them. Then the female will die. 10 days later the eggs will hatch and the cycle will repeat itself.
The unnatural process of the mating period is when we manage the mating process. Once the male moth hatches, we take the moth and place it in a small container. The container is kept in a cool room at a special temperature. This helps the male relax and so saves its energy for the mating period. 2 days later the female moth will hatch. The male moth is removed from the cool room and placed with the female. The male and female moth will be together for 3 hours. In this way, we will know that 95% of the eggs will be fertilized. Just as in the natural process, after mating the male will die. Then we take the female and place her under a cap in a quite, dark space for her to lay her eggs. Before she begins laying her eggs, the cap will be tapped around the sides. The vibration will force the female to urinate before laying her eggs so as to not to urinate on top of her eggs, once laid. She can only urinate once in her life. As soon as she urinates, she will lay her eggs. Then as the natural process, after the female laying her eggs, she will die.
When she lays her eggs, she will naturally place them next to each other and in a circle. Should eggs be placed on top of each other, this may indicate a disease.
The eggs with no urine on will stay alive for 3 months. Now, during those 3 months we must decide when we want the eggs to hatch. When we want the eggs to hatch, we dip the eggs in Hydrochloric Acid. The acid will be diluted with water. ( 30% acid and 70% water ). This acid solution will be similar to the concentration of the female moth’s urine. 10 days later the eggs will hatch. From the eggs the cycle will then repeat itself.
The Silk Worm
- The big white front part is not the head of the silk worm. The part that looks like the mouth of the silk worm is its head. The silk worm does have eyes but can’t see a thing, it can only separate between day and night. It can eat better during the day than at night.
- A human being only has 3 breathing holes. A silk worm has 20 breathing holes. 10 on each side.
- Every silk worm has a silk gland. That’s how the silk worm produces its silk. The silk gland is sometimes removed and can be stretched up to a meter. This is used for Cosmetic Surgeries as stitches. As the silk gland is 100% protein, these stitches can be used for people with high allergies.
- Eye Spot... The Cresent spot, Star spot, Eye
Spot
- Cresent Spot... and Codal Horn have only one use.
- Star Spot... These spots and horn are used for
protection to scare predators away
- Codal Horn... The predator will think that it might
be in danger if he attacks this silk
worm.
The Silk Production
We used to farm with silkworms for about 12 years, but with the increase of agriculture and insecticide drift in the area, it has become not viable to farm them any more. The poison sprays throughout the area and affects the mulberry trees. The leaves were picked and fed to the silk worms, so killing the silkworms. We then began importing silk as a raw material, from China.
When we get the cocoons, we boil them in Bicarbonate of soda and water, which softens them. The cocoons are very hard because of the seresin (glue or spit of the silk worm) that the worms use to protect themself from any danger. Once the cocoons are boiled, we make a small square under the water and stretch it into a rectangle (8 x 12cm). We put 5 of these cocoons on top of each other making a thicker rectangle.
We then take the 5 cocoons in the rectangle and stretch it onto a big square (30 x 30cm). Nails are used to hold in this stretch in place.
This process is repeated 5 times, which makes a square of 25 cocoons. It is then removed and air dried. After the square is dry, the corners and sides will be thicker than the centre. We will then take another square, put it on top of the first, which will make it 50 cocoons. This thicker 50 cocoon square will be rubbed to get fluff and even out the thicker corners. This will be stretched into the batting that then makes up the duvet inner.
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