Silkworm update

Last night, three of the six Eri Silkworms shed their fourth skins, entering the fifth and final instar.

Here, you can see a fifth instar worm (above) and a fourth instar (below.) The fifth instar has much longer points on its knobby body. The skin will probably shade more toward the same white as the skin gets a little older.

The bristles look like they might hurt to touch, but they don’t. They have little hairs growing out of the ends. The spiracles (the black spots along the sides, which mark the breathing holes) are larger and more pronounced.

A close-up of the Super Turbo Speed Eating Head. With the much larger jaws, the worm is able to do some serious leaf damage. I don’t know if the same statistics apply to the eri worms, but the bombyx worms eat something like 90% of their total food intake in the last instar.

A close-up of the back end of the worm. It has only six true legs like any insect; those are all at the front. Behind that are prolegs, which help it hold onto the leaves. These suckers have a GRIP. The mulberry worms can hold on, but nothing compared to these guys. At the back are the powerful anal claspers. They are so strong that if you pick up the worm by the front end, it will tear in half rather than let go. Come on, admit it…. you’re jealous. And no, I didn’t learn about the rip-in-half part from experience, I read it in a book.