Silk worms, threads, feed types and their composition

I saw a caterpillar or silk work eating அரளி leaves, does the composition of the threads vary based on their feeds like mulberry, arali leaves, guava leaves, mango leaves, banana leaves, jack fruit leaves and so on.  If so, then the threads be useful for various different needs, isn't?  

Similarly, different types of caterpillars go on to become moth or butterfly exhibiting differed color in their wings.  

Is it not possible to identify their Properties or genes that influence this and to engineering them to exhibit their colors during cocoon stage, enabling different color threads to be produced from them naturally with out the need for dying process? 

The Farmers themselves could then be selling cocoons or silk threads of different colors. 

This would mean that the pollution from clothing Industry is addressed at its roots itself, enabling environment friendly clothing industrial production. 

Similarly, we can generate or produce cottons from cotton trees that naturally produce colourful cottons using genetic engineering or crops. 

What do we think or say about this idea?