The Silk Road and the VERY Hungry Caterpillar

Our farm property has been blessed with three large mulberry trees. Every summer my mother and I would go and pick the juicy berries for baked crisps and jams. However this year the mulberry trees also served a different purpose. I decided to branch out in the fiber world and attempt to raise silkworms.

      I absolutely love the texture and shine of silk and it's a very strong fiber yet also light, so it can be very versatile. Unfortunately, not many people realize that the majority of the silk produced today involves the process of boiling the cocoons with the living worms still inside. Not only is this sad but also cruel. However, after doing a lot of research I came across something called "peace silk." 

     Peace silk is a process by which the cocoons are harvested after the moths have hatched out. This means none of the silkworms/moths are harmed. The little creatures are allowed to live out their full lifecycle. I decided that peace silk would be a great way for me to raise my silkworms. And of course In order to raise silkworms you need lots and lots and lots and lots and LOTS of mulberry leaves as this is the only thing they will eat.

     Silkworms are such interesting insects therefore, I would like to elaborate on how I raised these amazing little creatures. I hope that you read along and take part in the journey along the Silk Road and maybe even try it yourself!

  The first step was planning for the worms (which are technically caterpillars even though they are called worms) when planning you must make sure you time  the hatching of the worms with the mulberry trees in your area. Newly hatched silkworms enjoy eating younger tender leaves so you need to time the hatching right when the trees begin to get their new leaves in spring. Because I live in Indiana this puts the hatching at about early to mid May. Once you know when you want them to hatch you need to order your silkworm eggs. It can be tricky finding a place to order from and after searching around on the web I ordered mine from www.mulberryfarms.com I chose to order two thousand eggs but from now on I will only be raising five hundred to one thousand eggs at a time as they are much more manageable in smaller numbers.

The eggs arrived in a plastic dish and are very tiny and gray in color. 

I carefully removed the eggs with a paintbrush and divided them into three plastic food storage containers with holes poked in the lids. I also crumpled up a damp paper towel and placed it inside the containers but making sure it wasn't touching the eggs. This provides moisture for the unhatched worms. However too much moisture can harm them, if there is water condensing in the containers, then the worms are too wet. 

     About ten days later the eggs begin to turn a blue color. This means they are about to hatch. The worms are extremely tiny and fragile after they emerge from the shell and they immediately begin to search for and eat food. It is imperative that they eat as soon as they hatch or else they will dry up and perish. Below are newly hatched worms.

This marks the beginning of what feels like endless mulberry leaf picking. The worms won't each much at this phase only about a few handfuls of leaves twice a day but by the time they are a month old they will be consuming close to 50 pounds of leaves a day!  A few days after they hatch, they will shed their skins and enter the second phase or instar which is what they call the phases of silkworm growth. There are five instars in the silkworm's life before it spins its cocoon and turns into a moth. The first instar begins as soon as the worm hatches and the rest follow after each molt. The fifth instar is when the caterpillars will spin their cocoons. Below are second and third instar worms. 

Once the worms move into the third and fourth instar they will need moving into bigger containers. I used five long plastic containers for under the bed storage. I left the lids off the containers but did cover the tops with mesh fabric secured with binder clips. I clean the containers by picking the worms out and placing them in a separate bin while I empty out their container. I clean the cages out about once or twice a week. Below is one of my cages.

The caterpillars will begin to drastically grow in size. Silkworms will grow ten thousand times their original size! This is the equivalent of a baby human growing up to weigh as almost as much as twenty five cars! And the silkworm can accomplish this feat in only one month! below is a picture showing the amount of growth in just two weeks.

Because of this massive amount of growth they have to eat a massive amount of leaves. I found myself picking leaves three or four times a day with about a garbage bag full. I soon realized that my three trees wouldn't be enough as I didn't want to over pick and harm the trees. 

     Luckily, I have some super amazing friends who have an astounding amount of mulberry trees. They were also willing to help pick leaves as the worms entered the fifth instar. Fifth instar worms will consume the same amount of 80% of all the leaves they have eaten over the past four instars. This is an incredible amount of food! The entire time I'm picking leaves all I could think about was the book "The Very Hungry Caterpillar."One of my favorite things about feeding these little guys is the sound they make. You can hear all their tiny feet moving and jaws chomping as they climb over and eat the leaves. It sounds like rain pattering on a roof. It's strangely peaceful watching the worms much away creating what sounds like a mini rainstorm.

     Finally after weeks of dedicated care and feeding the worms began to spin. When the worms are getting close to spinning time they will need something called a mountage which is a frame for them to spin their cocoons in. I confess I wasn't very prepared for this part and I ended up using a couple different methods. The first method I used was cut up paper towel tubes. The worms love these but I unfortunately didn't have enough for each worm to spin in. So I needed a plan B. I trimmed off some dead tree limbs and laid them out in the cages. This method works but unfortunately it makes it very difficult to feed any worms that haven't spun and the cages become covered in silk making them look like Mirkwood Forest. It's very difficult to move anything around for cleaning too, because once a worm begins to spin it cannot be disturbed otherwise it may die. So plan C. I picked up some chicken wire from TSC and bent it back and forth created what looks like a giant wire crinkle cut chip. I placed these wire frames on top of the branch pile. The worms weren't too keen on these but did eventually climb up and use them for spinning. I think next year I will either create a cardboard grid or collect a lot more paper towel tubes for montages. 
     Once the mountages are ready the worms have plenty of space for spinning. The first thing they do before spinning is that they stop eating. They will begin to turn a yellow color and shrink slightly in size. They will select a good spot for their cocoons then spin a basic frame work. When the worms spin they move their heads back and forth in a continuous figure eight pattern over and over.  Below is a time lapse video showing how they move back and forth to shape their cocoons.
     

   This builds up and shapes the cocoon. It takes the worms about three days for them to complete their cocoons. Great care must be taken not to disturb the worms during this time.  

Once all the worms are done spinning the cocoons can be removed from the cages. In traditional silk raising this is the time when the cocoons are boiled to kill the developing moth. But since I'm doing peace silk I will be removing my cocoons in order to empty the containers of all the branches and set up a hatching station back in the same containers so that the moths will have the proper environment for when they hatch. Below is a picture of about a fourth or so of the amount of cocoons I harvested.

 Next I emptied all the leaves and empty mountages out of the containers and washed them out. I placed paper towels down on the bottoms of the containers and slowly lined up the cocoons. The paper towels help keep the cocoons from sliding while the moth is trying to hatch. As you can see my dog Teddy was very fascinated with the cocoons. He absolutely loved the sitting and watching the worms and now he is obsessed with the cocoons as well. You can see how I have the cocoons lined up in the picture.

 It took the cocoons 15 days before they began to hatch. I was surprised at how tiny the moths were! As soon as they emerge from their cocoons I placed them in a large container lined with wax paper on the bottom. The moths will mate and lay eggs in this container. The wax paper is used for when I collect the eggs after mating, so I can save them to hatch for next year's silkworms. I then collect all the empty cocoons and save them until I am ready to process them for their soft silk. Below is an empty hatched cocoon.

      Silk Moths do not have mouths and cannot eat so you don't need to provide any food or water for them. Unfortunately, the moths do not live long, just long enough to mate and lay eggs. However at least they are able to complete their lifecycle naturally.  Below is a male moth sitting in the palm of my hand.

 You can tell a male and a female apart because the females have smaller wings and larger abdomens. Almost immediately after they hatch, the moths will mate. The female will secrete a hormone that drives the males crazy as they desperately follow the scent. This is called "scenting." The moths will mate for 12-24 hours. After mating the female will begin to lay her eggs. Each moth can lay between 150 to 300 eggs. The eggs will be a light yellow in color but will darken after a day or two until they are gray. Once the eggs turn gray they can be stored in the refrigerator until next year. Any eggs that don't turn gray are likely infertile. The eggs can be stored in the crisper drawer of the fridge in a jar or freezer bag. Sadly after mating and laying eggs, this marks the end of the silk moth's life. But the journey will repeat again next year when the eggs hatch in the spring!

The life cycle of the silkworm is truly amazing! I hope you enjoyed reading along and I look forward to posting again on how I am going to use all the empty cocoons.