Adventures in medieval silkworm rearing, with emphasis on the joy of the insects rather than the silk they produce.
Wednesday, April 22, 2009
Yesterday I had four males and four females, one newly emerged. Three of the males died, and the one female who had just emerged had a problem getting out of her pupal case. I tried to help by pulling off the pupal case, but I tore her abdomen and she started to leak hemolymph. She wasn't going to survive so I killed her quickly. Next time I'll know that I need to be much more gentle.
I still have had no couplings. I had heard that sometimes in enclosed spaces the males are so bombarded with female signal that they can't find her to mate. In these cases they either need to be put in a larger space to mate, which I can't do, or be hand paired. I found a youtube video about hand pairing moths, so I went and tried it with the remaining male and the three females. I could not get the male to couple with any of the females. I picked up one of the dead males and examined his reproductive parts. They looked different than the living male, so I looked at all of the other dead males, and they looked different than the living male too.
Right now I have some theories as to why I've yet to get a breeding pair to couple. First, the three dead males couldn't couple with the females because of the confined space. Then they died. Second, the living male has abnormal reproductive parts, or something, that is preventing him from coupling. It looked like he wanted to mate with the females (I tried them all with him) but he just could not get it done. I spent over an hour trying, so I was very patient but nothing happened.
So I'm kind of in trouble here with my moths. I just need one male and I'm in business. I have four cocoons left that have not emerged. If I get a male I'll try hand pairing again. I hope that one of the females lives long enough to get fertilized. If not I will have to start all over again with trying to import cocoons.
So I now have three boys and a girl. None of them has been able to mate with the female.
I don't know what's going on, but I get the feeling that the boys are kinda dumb. The female sits still and even bends her abdomen towards them as they crawl on her, but none of them has been able to "seal the deal".
This evening I had a female moth eclose. I was able to take a video of it, but I have to warn you that I let my two girls watch so they provided commentary during the process. They also kept bumping my arm that was holding the camera, so it's a bit shaky at times.
After her wings expand I will pair her with one of the males in a paper bag and wait for eggs. As far as worm food goes, my oak buds are getting bigger and greener each day, but I don't have real leaves. I'm trying not to panic about it just yet.
I consulted with the silkworm rearers mailing list regarding my problem with the moldy cocoon. I got a lot of very good information and suggestions, and so have taken the following actions -
It's likely that 52 degrees F is too warm for A. pernyi to remain in diapause, so my pupae might develop and attempt to emerge from the cocoons. It's too late to put them at a colder temperature because if they've developed this might kill them. My best bet is to get them warmed up again and take them out of diapause, so I have all the cocoons in a warm room and separated by colony.
It's most likely that the moldy cocoon resulted from the dead moth inside, so for some reason the moth developed and then died. It's good to know what caused what - as in the death casued the mold and not the other way around.
Since there are no leaves on any trees, I'm attempting to force some oak branches to develop leaves sooner than they would normally. To do this I've cut some branches with buds on them and put them in the warm room in the bucket of water. I did this a few years ago and was able to get a few tiny leaves, which would be enough for me if I get a moth pairing and eggs before the trees outside fully leaf out for the spring.
If I can't force any leaves from my cut oak branches, some good folks from the list who live in southern states have offered to ship me fresh oak leaves. They say they have plenty of leaves down there now. I think this is fantastic, and really very nice of them. I hope I don't have to ask them to do it for me, but if I get desperate I might have to get some oak leaves Fed-Ex'ed to me.
Yeah, we bug people are kinda weird like that.
Anyway, I have five cocoons from colony B and six from colony C. There was one cocoon from colony C that had a dark end, so I snipped it off to see what it looked like inside. I saw what appeared to be a perfectly normal pupa butt. I poked at it a little but could not tell if it was moving or not. I decided to leave it alone and see what happens.
Worse case scenario - I won't have any moths or any pairings. Then it's back to trying to find a supplier.
Next time I'll know - 52 degrees is too warm for diapause!
I haven't even taken my cocoons out of diapause, and I've already lost one.
I'd been keeping my cocoons in a wine cooler fridge at 52 degrees F, in narrow mouthed containers. The mouths of the containers are stuffed with batting that I'd wet every so often with water to keep a little bit of humidity in the containers. I was afriad that the fan on the cooler would dry them out, and I was also afraid to put them in an airtight container (even though I've heard of folks doing that).
Today when I checked on the cocoons I found one that was moldy. There was more condensation int he container than I would have liked, which can only mean that I wet the batting too much last time. I dried the rest of the cocoons and shook the extra water from the container.
Then I cut open the cocoon to see how the pupa was. Unfortunately, it was dead. It looked like a moth, so for some reason it had come out of its pupal case. This is not really a good sign, and now I'm worried that some of the others have come out of their pupal cases as well. I'm not sure why they would do this, since they shouldn't be developing at all at this temperature. However, the rest of the cocoons look fine, and when I shake then I can hear them rattling inside their cocoons. This leads me to believe that they are still inside the pupal cases like they should be, but I don't know for sure and I don't want to cut open the cocoons to find out. I guess I'll just have to wait.
Also, I'm wondering if the moth got moldy and then died, or died and then got moldy. So which came first, the mold or the death?
In any case, I feel like I need to get those cocoons out soon, but we don't have leaves on the trees here yet. Come on trees! Lets get going!