Saturday, September 6, 2008

Picture Day

I took some time today to get some nice shots of the molting worms. All three colonies are in molt right now, and the large size of the worm makes it easier to get good photos. The younger worms look very similar to these as they are molting, except the color of the heads don't change as dramatically as the older worms do.

This worm is not ready to molt yet. Notice that the head looks dark and small compared to the body.

This worm has just molted, and the head is much bigger than in the last photo. The white head and face will darken over time. If you look closely you can just see very faint dots where the characteristic face freckles will show up when they darken. Also you can't really tell from this angle but the skin is very loose and baggy, giving the worm room to grow.

Here is a worm that has molted and enough time has passed that the head has darkened and the cute face freckles can be seen.

This shot shows the typical "prayer stance" that the worms adopt before they molt. The head is tucked down and the front legs are held up and together. If you look at the head you will see a cream-colored area right behind the face. This is the back part of the head peeking out because it is now too large for the head capsule. The worm will have to pop that head capsule off in order to molt and also to be able to eat again. When the head gets too big for the head capsule the mouthparts stop working, and so the molt begins.

Here is a shot of another worm waiting to molt. Worms that aren't molting will also take the prayer stance if they are disturbed.

Here are a line of worms waiting to molt.

Close up of two pre-molters.

Some worms spin short silk anchor threads before they molt. This helps them stay in place as they try to wiggle out of the old skin. It's best not to break these threads because an incompletely shed skin can cause major problems down the road for the worm. You can see the old skin hanging off the back of this worm.

This is a nice shot of the dark jagged mandibles of the worm. This worm has just molted so it's head is nice and light, creating a good contrast with the dark jaws.



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