Tuesday, October 14, 2008

Winding down

Things are coming to an end with my bug colonies. Colony A is all finished, and the return was pretty poor. I got eleven cocoons, and most of them are pretty poor quality. The walls of the cocoons are thin, so there is not much silk in them.

Notice that at the bottom of the picture there are pupae that did not spin cocoons. These bugs went through pupation without spinning. I got some of these in every colony. I also got some really neat pictures of the worms pupating outside of a cocoon.

To begin pupation,the worm gets short and fat and just lays on it's side, not eating or crawling. If poked they will do a little wiggle with their bottoms.

A few days later they will wiggle fiercely to get out of the worm skin. If they are in the cocoon this sounds very much like some animal caught in a paper bag trying to scratch it's way out. Right after the skin is shed the pupa looks very green and is soft. If you look closely at the head (the most green part) you can see the antennae and the wings closed around the body.

It only takes a few hours for the pupa to start turning brown and hardening on the outside. Here is a picture of the skin on the bottom, a green pupa in the middle, and a browned pupa on the top.

Like Colony A, Colony B is also finished and has no worms left. I got more cocoons out of it but not as many as I'd hoped. Seventeen complete cocoons and one cocoon that looks like a bowl. The worm in that one didn't complete the cocoon. The green worms on the bottom are not going to spin, and will just pupate with no cocoons.

Colony C, however, still has worms spinning. There are only about five worms left and at least one of them is fixing to spin right now. The was my best colony, and has gotten me 62 cocoons so far. Most are of a nice quality too.

I saved five cocoons from Colony B, and seven from Colony C. I kept each colony separate and put each in a wide mouthed container and stuffed the opening with cotton batting. I need to make sure that they get air, but don't dry out. Then I put the container in my cooling chamber at 52 degrees. That should be cool enough to activate diapause (overwintering) but not cold enough to make them sterile.

The rest of the cocoons and pupae went into the freezer. I'll just throw the pupae with no cocoons away, but the cocoons I'll take out at a later date and dry them.

I'm certain that the early disease had a large impact on the quality and number of cocoons that I got from each colony. Colony A was hardest hit and I got the most death and least cocoons from it. Colony C was the least effected, and it shows. Next time I will not try and raise that many worms at once. I'll start with one or two hundred eggs at the most. That should make it easier not to overcrowd them. It will also make it easier for me to get enough food for them. There were days where the back of my car was stuffed with large leafy branches that had to be put in buckets of water so they would stay fresh over night for the morning feeding. I'm really glad that's over!

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At October 11, 2009 6:53 PM , Blogger Raissa said...

i have a worm that didn't make a cocoon and is red like your pictures. Will it die or turn into something else? If something else, what will it turn into?

At October 11, 2009 8:41 PM , Blogger Serena said...


It will probably emerge as a normal moth. The worms don't have to make cocoons to transform into moths, so if it still wiggles when you gently poke it I'm sure it's still alive and fine.

Is it A. pernyi? Or something else? Depending on what species it is it might not overwinter as a cocoon.

At October 13, 2009 8:33 PM , Blogger Raissa said...

We don't really know what type the catapillar is. though mom said it wasn't a silk worm.


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