Tuesday, September 23, 2008

Oh deer! We're spinning.

I've been meaning to write about this for awhile, but I just haven't had the chance. Here is a picture of my weeping mulberry.

A few weeks ago it was beautiful, completely leafed and full. Then one night the deer came by our yard and almost stripped it. I'm very glad that I didn't have any B. mori that I had to feed, or I'd have been in trouble, Next year I'm going to get netting on it early to protect the buds from the squirrels, and then I'll leave it on to keep the deer off of the leaves. Honestly, they could have eaten ANY of the other crappy shrubs that we have in our yard. Why pick on my mulberry!!??

In bug news, this morning I saw that I had two spinners. They had just started the beginnings of the cocoons, and by this evening they had completely enclosed themselves in silk.

I have one spinner each in colony A and B, and I think I have one starting in Colony C. I think I may have figured out a spinning structure for them. I took short sections of used oak twigs and tied them together in the middle to form bundles of twigs. I'm hoping the silkworms will crawl upwards out of the leaves to spin in the twigs. It would be much easier to raise these outside!

Something that I haven't mentioned is that the worms seem to prefer leaves from certain trees. I'm not great with identifying oak trees, but I'm pretty sure that the oak leaves I collect out at the farm are pin oaks. The worms will eat the pin oak, but they seem to far prefer the leaves from our church's oak tree out back, and the oak leaves from our neighbor's oak tree which I think are the same species. Compared to the pin oak the leaves are a much darker green and the leaves are not as skinny and spiky as pin oak leaves. I'll have to see if I can figure out what species the preferred trees are, because I think it's interesting that they have favorites within a species.

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Thursday, September 18, 2008

The Infirmary

My worms are eating like crazy, and getting really big.

I still have fatalities in all Colonies, but they are mostly in Colony A. They seem to be bugs that haven't been through the final molt and are not showing signs of ever getting there. They are small and don't evacuate their bowels or vomit before they die. They just get stiff and die. It's nice that they don't spew bodily fluids or liquefy, because that tells me that it's probably not a nasty virus or bacterium. However, since I'm getting mostly deaths in Colony A and that's the colony that had the illness, I'm assuming the worms that survived were affected in some way. Most of them are doing just fine, so all I can do at this point is feed them well and keep them clean.

The deaths that I've had in the other two colonies seem to be worms that haven't molted completely, or are having issues molting. You can see on both of these guys the flaky skin and yellowish color. The looked bad enough that I pulled them out into The Infirmary to get them away from the other bugs in case they died.

Compare them to this nice healthy worm, whose skin is smooth and a nice green color.

The Infirmary is just another container that I have set up to put the sick looking bugs in. I put the sick worms on a paper towel just in case they evacuate their bowels or vomit before they die. Most of them seem to die, but at least they do it away from everyone else. I've had five or six that seem to recover and I've been able to put them back with the others when I'm sure they are doing well.

Right now I've got some interesting worms in The Infirmary. This one seems to have a rectal prolapse. I had one other worm do this and the next day it was just fine, so we'll see what happens to this little guy.

This one has a black foot. He seems to be eating and getting around okay, but I want to keep him segregated. I need to take some time and look up what this illness might be.

This poor worm has a rectal prolapse and a black foot! He's a big fella too.

Should be one more week until I get spinners! I can't wait!

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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.


Friday, September 5, 2008

Count update

Last night I counted colony B. Out of 273 eggs I have 194 worms. That makes a total of 553 worms from 800 eggs, which is 69%. I lose maybe one worm every other day, but they aren't sick. The dead ones that I find always seem to have had some sort of growth or molting issue. They are small and far behind the others in the colony, or have old shed skins stuck to them that they can't seem to get rid of.

Overall I'm really happy with how they look right now. They are fat, green, and very happy. Since the rearing containers have very good ventilation and I'm cleaning the containers and the room carefully and vigilantly, I seem to have eliminated the sickness issues.

I am concerned about what I'm going to do when they start to spin. When B. mori are ready to spin they turn kind of a translucent color and get sort of bloated and sluggish, so it was easy to watch the colony and separate the spinners from the eaters. These A. pernyi don't seem to change much in appearance. With my last batch the only reason I was able to tell which ones were going to spin is because I could tell that they had done a "gut dump". This is exactly how it sounds - the worm evacuates it's bowels before it spins so that it doesn't have to poop inside the cocoon. Makes sense, huh?

Anyway, it's important not to disturb the spinning worms. They can take a few days to complete the cocoon and if disturbed during the process they can stop spinning and never resume. They will still pupate and develop, just without spinning a complete cocoon. Since I'm after the silk I really don't want incomplete cocoons. Once some of the worms start to spin in one colony I'm going to have to figure out how I can clean the container without bothering the spinners. With my last few worms it was easy to separate them. This time it's going to be impossible.

If I can't clean as thoroughly as I'd like I'll need to lower the temperature and increase the airflow to try and lower my chances for disease. That's the best plan I have so far. I guess I'll have to just see how it goes. In ancient China these worms were raised outside on trees. I can see how that would be much easier to deal with. All the poop just falls to the ground, they find their own food, and they can spin in the leaves when they are ready. Of course they would also have to hope birds don't come by and have a snack. I'm sure those nice fat green worms would make a nice meal.

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Tuesday, September 2, 2008

I must have been crazy...

.. to think that I could take care of this many bugs. They are eating like cows! Here is a picture of what they eat in a 24 hour period.

The bad news is that bringing all those oak leaves and branches into my house means that I'm also bringing in all sort of other little critters. There are assorted spiders, mites, other caterpillars, and the occasional juvenile praying mantis. I've been trying to catch them all and let them go, but the spiders mostly get away from me. Anything little that crawls off into the insectary seems to get getting caught by the spiders who have set up shop in the corners of the room. I'll have to do a thorough cleaning once all the spinning is completed.

The good news is that I have the sickness under control and have not had any more deaths. Colony A is beginning the last molt, and then the eating should bump up another notch. It's going to be a very busy next three weeks.

I did a bug count of colonies A and C tonight, and here how the numbers worked out -

Colony A - 259 eggs, 169 worms (43 died from the illness)
Colony C - 268 eggs, 190 worms.

I'll do a count on colony B tomorrow or the next day. Assuming the numbers are close I should have 500+ worms.

Man, that really makes me sound nuts. I will never again raise this many bugs at once. It's just too much!

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