Saturday, January 17, 2009

Into the moult


Silkworms, I have noticed, seem to have two sets of legs: six insect legs on their front segments and then eight, more-rudimentary ones on the segments further back. (Added later: I have since discovered that the legs on the front are thoracic ('real' insect legs) on the thorax; while the ones at the back are prolegs ending in suction caps called crochets. These are on the abdomen).

I clean them out every day, removing their tiny black walnut-shaped droppings and the food they haven't deigned to eat. This is to prevent mould, which is dangerous to silkworms.

Their food comes in plastic tubs and has the consistency of butter. It is supposed to be grated into their home, but really it is too soft for that. I usually end up with a few small pieces and hope that will do. I think it does, because if I listen carefully I can hear my silkworms eating. It is a contented munching sort of sound - and I think that if I could amplify this it would be quite relaxing.

Quite often they stop moving altogether and sit with their heads in the air. They are the texture of a creamy limestone and look so much like statues of themselves that I have been tempted to prod them to make sure they are not dead. However, I have just read on a website that this means they are getting ready to moult. One of them - the small pale one in the centre right of this picture is doing that now. His head seems to have changed a little too - his eyes are protruding and yellow. At least I assume they are eyes. (Added later: these are fake eyes. The real eyes are smaller and below the fake eyes).

Now a moulting silkworm should not be touched and I feel I am a little like a midwife or an expectant father, wondering what will happen next. I suppose, like all metamorphosing creatures, the silkworm is bristling with stem cells. Somewhere, perhaps on the inner layers of the old skin, there are cells reproducing and becoming something else as they mature and are bombarded with chemical messages: a part of a wrinkle or pigment, grow a bristle or a pore. After a few days a new silk worm will appear - his skin a little tender and vulnerable but otherwise just as perfect as he used to be - part of the series of little miracles which turns the egg into the moth.

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