Spinning Cocoons Photoshoot

What a fascinating event! The silkworm releases liquid silk from the two silk glands near the lower jaw which then flows through the "spinneret".  The two silk glands constitute approximately one-quarter of the silkworm larva's mass. The fluid hardens into fine silk threads as soon as it contacts the air. At first, the caterpillar fixes supportive threads of silk that will hold the cocoon in place. Then it swings its head from side to side in a figure-eight movement, encasing its body in silk. For about three days the caterpillar spins the continuous silk thread until it is fully encased in its beautiful protective cocoon of silk. It can spin from about 600 to 900 metres of continuous silk thread! The silk is beautiful and shines in the light (lustrous).  It is amazing how the silkworm "stands" on the silk thread and then maneuvers within the cocoon to produce the perfect cocoon shape. 

 

Click on the photo to enlarge. You can see the spinneret and the silk thread.

A video worth watching to see the silkworms spinning is entitled 

"Silk Pavilion"  https://vimeo.com/67177328

A Place to Spin

Cardboard rolls worked best here. A piece of mulberry leaf seemed to help them settle...

...but some were still hungry and went searching for food.

How fat can a caterpillar get? He (or she) seemed too fat to spin!

Nearly every vacancy filled!

At Last...It's Time To Spin!

 The silkworms, now ever so fat, stopped eating and started to wander around as if looking for something. This is the day before spinning began.

34 days after the first larva hatched, the first silkworm started to spin in the corner of the box.

 Different setups were tried to provide a suitable place for them to spin. This was only 50% successful as they were unsettled and kept wandering around.

However one started spinning......

And another......

The silk was beautiful and shone in the light.

Other caterpillars were still looking for a good place to spin... "Is there any room in here?"

One caterpillar escaped into the living room...

Anatomy of the Silkworm Larva (Part 2)

Three pairs of Thoracic Legs

Front legs of younger silkworm larvae.

Front legs of older silkworm larvae.

Holding the silk thread using the front (Thoracic) legs.

Four pairs of Abdominal Legs and the Caudal Leg

The back legs securely grip the branches.

Gripping with the "clasper" and passing by a shed skin...

Young  larvae.  Feet are for walking!

Lots of stalk "highways" for travelling on!

 

Caudal Leg & Horn

The Caudal Leg. A wonderful "clasper"!

The back Horn and Caudal Leg.

Frass or excrement can be used as fertilizer. Lots of cleaning needed!

When the larvae grow bigger, a wire base in the box enables the waste
to fall through for easy removal.