It's been many years since I kept silkworms and I've never reared them. Recently I bought some small ones from Coastal Silkworms and they did fantastic. I only lost about two out of two hundred babies. I was really impressed with this company and how healthy the worms were. Anyways I'm going to try raising some now and although I've done lots of searching I cannot find info on how humid the cocoons need to be kept. It's extremely dry here but the worms did just fine with no extra humidity. No shedding problems or anything. However I'm concerned maybe the larvae inside the cocoons need extra humidity to keep from drying out during pupation? The only thing I've read regarding humidity is that the eggs and new born caterpillars cannot be too dry. On the other hand many sources warn that older worms should be kept dry to prevent mold or bacteria growth. Any insight or links would be greatly appreciated. Like I said I did do a lot of searching before asking here!!! Thanks again.
Do silkworm cocoons need humidity?!!!
- Thread starter AZChamFan
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nightanole
Chameleon Enthusiast
They are in a shell, inside of a hard cocoon, you are fine. Just wait for them to puke their way out as normal.
I understand that but it doesn't necessarily mean they can take really dry conditions. I've hatched cocoons such as Actias luna and Hyalophora cecropia in the past and if I did not keep them somewhat humid the moths came out very small and deformed. Many tropical butterflies must be kept extremely humid during this stage or they will have issues, even though the chrysalis has a shell. I was just wondering if anyone has seen this issue in silkworms. I will probably just try it and see what happens. If they have issues then I'll keep them more humid next time! I just didn't want to mess with providing the extra moisture if it's not necessary.
kelly_girl199
Avid Member
I agree with you on humidity. I had 5 recently hatch. 3 had withered wings and two had perfect wings. I would say it's def a humidity issue. It's the same with hawkmoths. I had two emerge once and one had withered wings, other did not.
Ok I broke down and made up a container which will create and hold some humidity!!! It can't hurt and it will help prevent the delicate eggs from over drying when they are laid. Thanks for the input - it was the little bit of encouragement I needed!!!
Andee
Chameleon Enthusiast
It doesn't matter for the silkworm moths to have withered wings or not. They cannot fly with them and they do not use they for mating purposes. I have never have issues with shriveled wings unless the moths were in a cramped space when they emerged and didn't move, or got stuck on the silk of their cocoon. They don't need excess humidity put in, and in fact I could see it being somewhat detrimental as the cocoon would hold the moisture easily and could mold. Freshly laid eggs do not need to be worried about drying out. As soon as they turn grey, which would happen in an hour or two, they should be moved into a ziplock bag and put into a refridgerator for 2-3 months no more than 6 months. They need a diapause stage so that you get a higher hatch rate. I don't honestly give much humidity to my young worms. Even freshly hatched. I put the eggs next to a reptile heat lamp and keep either a fresh leaf in the deli cup with the waiting eggs or some fresh chow, the excess moisture put off from them is enough to provide for the eggs, and I leave a decent sized crack in the deli cup tops to let airflow in and out. Mold is more of an issue in my opinion with eggs.
Thanks Andee. Very good information. I understand the moths don't need their wings but I just thought if it's affecting them in that way then maybe it's having other negative effects as well. I will be very careful not to keep things too humid. My goal was honestly never high humidity, but just average humidity. Here in AZ we have been having below 10 percent humidity and in the house with the air conditioning it's even drier. It really is extreme!!! Also the bad experiences I've had in the past with not just shriveled wings but small unhealthy moths of other species concerned me! I'm not arguing with what you said - I just think I need to find a good balance. Thanks again for the great information - it helps a lot.
@Rex561 This should answer a few of your questions, https://www.chameleonforums.com/threads/silkworms-care.153416/
It was a great help to me.
It was a great help to me.
kelly_girl199
Avid Member
Thanks for the info!!Btw I have 9 little silkies that hatched and are growing!!they came from the first batch of silkworms you sent me. Most look zebra so far but there are some white!! I only did a few to test out since it was my first go. But now I have a couple hundred eggs incubating past week. Several look like they are about to hatch. The ones I have now are about a half inch or so.
Just wanted to give a little update on how things are going. I ended up with 30 cocoons, and decided to keep 20 of them in a container which would maintain around 60 percent humidity, and the other 10 were kept at the humidity of the house which was close to 10 percent. The cocoons which were kept at 60 percent humidity were never misted and there was never condensation in the container - per Andee's advice I was very careful in this regard. My goal was simply to keep them at an average humidity level with no actual wetness of any kind contacting the cocoons.
There was a noticeable difference between the batches. All 20 of the cocoons kept at 60 percent humidity hatched into nice looking moths. However only 8 of the 10 cocoons kept at 10 percent humidity hatched, and the moths were just a little smaller and the wings were bit shriveled on many. These cocoons also took about 5 days longer to hatch. I realize the wings are not used, but I can only assume that if the wings are not as well expanded then the moth may be somewhat dehydrated and this could affect its overall health and the health of the eggs. Even though the pupae is inside a tough cocoon it's still a living and breathing organism and there must be some air exchange. Both batches laid quite a few eggs, but many of the eggs from the low humidity batch began to sink in the middle (I have a microscope to see them) where the others did not. I'm referring only to fertile eggs in both cases. I did not keep those eggs that sank. I did refrigerate many eggs, but I also kept some out because I was curious how they would do without refrigeration and wanted some babies right away anyways!! I was amazed that a VERY high percentage of those eggs hatched in a very short time. The babies are thriving. I've included a photo. There are about three days difference between these so the sizes vary a little. It's really hard to see the smallest ones in the photo but I'm guessing there's about 100 to 150 babies in this batch. It's always more than it looks like! So anyways in the end I have to say that in my case the humidity made a difference. However my case is unusual since I live in the desert and it's EXTRA dry here. I feel that in the vast majority of cases average household humidity is fine for the cocoons, but extreme dryness does seem to affect them. This is so much fun raising them - I thought it would be more difficult! I have only lost 2 babies so far, and those were probably damaged during transfer.
LINK ABOUT COCOONS -
https://www.quora.com/Does-a-cocoon-breathe
There was a noticeable difference between the batches. All 20 of the cocoons kept at 60 percent humidity hatched into nice looking moths. However only 8 of the 10 cocoons kept at 10 percent humidity hatched, and the moths were just a little smaller and the wings were bit shriveled on many. These cocoons also took about 5 days longer to hatch. I realize the wings are not used, but I can only assume that if the wings are not as well expanded then the moth may be somewhat dehydrated and this could affect its overall health and the health of the eggs. Even though the pupae is inside a tough cocoon it's still a living and breathing organism and there must be some air exchange. Both batches laid quite a few eggs, but many of the eggs from the low humidity batch began to sink in the middle (I have a microscope to see them) where the others did not. I'm referring only to fertile eggs in both cases. I did not keep those eggs that sank. I did refrigerate many eggs, but I also kept some out because I was curious how they would do without refrigeration and wanted some babies right away anyways!! I was amazed that a VERY high percentage of those eggs hatched in a very short time. The babies are thriving. I've included a photo. There are about three days difference between these so the sizes vary a little. It's really hard to see the smallest ones in the photo but I'm guessing there's about 100 to 150 babies in this batch. It's always more than it looks like! So anyways in the end I have to say that in my case the humidity made a difference. However my case is unusual since I live in the desert and it's EXTRA dry here. I feel that in the vast majority of cases average household humidity is fine for the cocoons, but extreme dryness does seem to affect them. This is so much fun raising them - I thought it would be more difficult! I have only lost 2 babies so far, and those were probably damaged during transfer.
LINK ABOUT COCOONS -
https://www.quora.com/Does-a-cocoon-breathe
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Andee
Chameleon Enthusiast
I always love learning about insects, I usually have to deal with too much humidity. I have to keep them away from my reptile room specifically. XD
I was wondering what temperature you keep your baby worms at? I see some different opinions on this. I have been keeping mine at about 85 degrees and they seem fine. I'm also maintaining about 50 to 60 percent humidity for them because otherwise the chow dries out extremely fast here!!! Once again I'm careful that there is no condensation anywhere and I change the chow daily and keep a close watch for mold. I simply put a fresh "patty" of chow right next to the previous day's chow and by the next day most of them are on the newest chow and then keep repeating that process. This way I don't need to manually move very many at all. I know as they get older the humidity and temperature requirements are not as strict - when I bought the original batch the worms were about 3/4 to 1" and I kept them at room temperature which was about 77 degrees and lower humidity and they did great. Anyways thanks as always for any comments!
Andee
Chameleon Enthusiast
I keep mine at room temp. I also don't incubate the eggs really. I put them next to the hood of a reptile lamp... room temp for me is around 60-75. I do little tiny shavings of chow.... but my guys I manually move over. At every stage. I also don't use a paintbrush to move them. I don't have an issue with squishing or randoms die offs because of bacteria etc. Honestly if mold happens they can go several hours without me noticing (from the looks of the mold growth) before I have to worry. But I have bred mine to specifically breed out the weaker worms and ones who die and get sick easy. My last batch of moths for some reason were extremely infertile after trying to use a commercial batch to introduce to my colony. I didn't allow them to be introduce into the gene pool.
JoeDigiorgio
Avid Member
I just ordered eggs and chow from Coastal. I'm excited to add silks to my rotation.
Hope I don't get in trouble for this but I just wanted to mention that although I had GREAT success with their worms, I like Mulberry Farms chow a whole lot better. Might just be personal preference but MF chow is more finely ground (and much more readily eaten in my experience) and even more green which would indicate more leaves and less filler. It's just something to consider if you have any issues.
JoeDigiorgio
Avid Member
Thank you! This is my first time with them so I'll keep that in mind for my second chow order. Hoping to not have to order eggs or worms again.
