Thursday, July 31, 2008

Cooling it

Things are moving right along with my silkworm breeding.

Right now I have 800 eggs from three pairings. My goal is to keep them separate so when I choose my cocoons to overwinter I can choose five or six from each brood. That way I can control inbreeding to some degree. I can't eliminate it, but I can try and minimize it as best I can.

Yesterday I removed the males and females from the paper bags and put them in a container. When I opened the first bag a lot of wing scales came billowing out, so I quickly closed the bag and got the vacuum cleaner. I turned it on and kept the nozzle very close to but not in the bag so that I could open the bag and not have scales floating all over in the air. The wing scales from some moths are very irritating to the lungs, and I don't need to have breathing issues because of this project.

I made sure to keep the moths that had already bred separate from the ones that have emerged but not bred, just in case I get any more emerging. The moths are all pretty beaten up from trying to fly around in the bags and containers. This is the best looking one and big hunks of wing are missing.

After I moved the moths I cut the paper bags up so that the clumps of eggs were on small sheets of paper. Then I arranged the paper strips in the bottom of petri dishes, labeling the broods A, B, and C. I had read that you should mist the eggs every third day, so I misted them yesterday.

However, I have a problem. The eggs are due to hatch while I'm at Pennsic. I have a theory that I should be able to cool the eggs to slow down their development so that they don't hatch until I get back. At the current temperature of 80 degrees in my insectary the last batch of eggs hatched in ten days. That would put these eggs hatching on August 5th. I leave on the 4th and get back on the 9th. I need these eggs to stay eggs for five more days.

When I heard that the cocoons should not overwinter in the fridge, I went searching for a small used fridge that I could just turn up high and get it around 55 degrees. But when I was searching online I found that they make small, inexpensive wine chillers that have a digital temperature controls that you can set between 65 and 40 degrees. The bad thing about these is they don't get colder than 20 degrees below the room temp. This is not an issue for me since I don't want it much colder than that. I was able to find a small chiller on sale for $60 so I grabbed it for overwintering cocoons. However, I'll be using it much sooner than that. As in right now!

I called the USDA entomologist to confirm that I could accomplish delaying egg hatching by cooling the eggs. He agreed that it would work, and said 60 degrees should do it. So right now my eggs are in petri dishes in the chiller at 60 degrees. I think I'm going to modify the shelves so I can put the dishes on the shelf and put a pan of water on the floor of the unit. There is a fan in the chiller and I'm afraid that the eggs will dry out if I don't keep the humidity up.

I'm trying to decide what to do from here. I just need them to be delayed five days. So, do I leave them in the chiller until I get back, or leave them in for another five days and then take them out before I leave and risk them hatching while I'm gone?

I'll probably take them out before I go and leave them some branches to eat if they hatch. I'm really hoping they don't hatch until I get back. Silly worms, you have bad timing! At least they are in a stage that I can control. If they had all hatched last week I'd be in a pickle since I can't take them to Pennsic and I can't leave them alone for five days.

So far no other moths have emerged, including my two from the first generation this spring. If I have no more moths tomorrow I'm going to stick them in the freezer. I can't have them emerging with nobody to take care of them. However, I really don't think I need any more eggs. 800 will be plenty!

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