Silk Worms

[TenebrousNova]

I originally bought this colony of over twenty silk worms to feed to my chameleon, but then I decided it would be interesting to try raising them. Bombyx mori are an entirely domesticated species and are completely incapable of surviving without human care. They have been selectively bred over the centuries for large cocoon size, silk production, egg laying capacity and digestive efficiency. Because of their domestic nature, the young silk worms don't seem to mind being handled and the adult moths are fearless. The males also apparently need assistance in finding a mate!

They will molt through a number of instars before spinning a cocoon covered with a thick layer of their namesake silk, which is unravelled by the people who farm them (This can be done without harming the pupa inside). Eventually the adult moths emerge and mate, beginning the cycle anew. 

Like I said, I didn't think I'd be looking after them so I didn't order food for them until today. Silk worms almost exclusively eat mulberry leaves and since I don't have access to that, I've ordered a sort of paste made up of the leaves. These caterpillars are fairly large already so they were able to cope without food for a few days.

Here they are! They have to be cleaned out quite often because as you can tell from the droppings, they will evacuate with reckless abandon in every nook and cranny. They will also leave strings of silk wherever they go.



As soon as I put in the mulberry leaf paste, they wriggled over to it and attacked it with a ravenous hunger. A few of them needed my help to find the food but are now happily tucking in.





Hopefully this will be a fun little project.

[TenebrousNova]

The caterpillars have already grown quite a bit now that they're being fed twice a day every day. I also have to clean them out just as often!
The largest individuals are just over two inches long now. Somewhere between 2 ½ and 3 inches they spin their cocoons.

[TenebrousNova]

Some of the silkworms are now pupating! Unfortunately they'll have to start again since their containers were due for a clean out and I had to move them to the container I prepared for cocoon spinning, but they'll be okay. At this stage the caterpillars shrink somewhat and turn a yellowish colour, and their silk glands now take up 20% of their body. It takes about a day and a half to spin the cocoon from a single continuous thread of silk that reaches about a mile long, and the actual metamorphosis takes between 1 and 2 weeks. I should have some photos for you guys of the adult moths then.

[TenebrousNova]

There's currently nine cocoons!

[TenebrousNova]

There is now a total of 20 cocoons. The last of the caterpillars that were developing too late were given to the chameleon- I felt a bit bad doing it but it is what I originally bought them for. I'm hoping the first moths will emerge sometime next week.

[TenebrousNova]

The first silk moth has emerged! This one is a male.



He's very calm and will walk onto your finger when prompted. Hopefully a female will emerge soon?

[TenebrousNova]

Today the first female moth emerged! She gives off pheromones shortly after emerging and even when I just took her out of the cocoon container for these photos, the male in the other container started wandering around with his wings buzzing frantically in search of her.





The male made a beeline for her when I put her in. That was the fastest courtship I've ever seen.



They will stay like this for up to 8 hours and then the female will start laying her eggs on the paper.

[TenebrousNova]

The third female has emerged today! Here she is calling the males...from my finger.



The round organs at the end are her pheromone glands, which she reveals to attract a mate. The males go ballistic when this happens.



The first female has laid her eggs today! She slowly walked around feeling with her ovipositor for an empty space and laid an egg every few seconds.



Within the space of an hour, she had laid hundreds of eggs and retracted the ovipositor. She'll die soon now that her task is accomplished, but she's succeeded in passing her genes on to a new generation. I'm going to have more silk worms than I know what to do with...and that's just from her. The other two females are currently mating and thirteen cocoons have yet to hatch!

[TenebrousNova]

The eggs laid by the first female started hatching a few days ago but I hadn't ordered their food in time! Luckily, the baby caterpillars held on long enough for me to feed them today. During their first instar they're dark and quite hairy.



I ordered their mulberry food as a powder assuming I could just mix it with water, but you actually have to cook it in a microwave. I won't bore you with the details but I fudged the measurements and then caused the tub I was using to melt, green sludge to get everywhere inside the microwave and the unpleasant smell of cooked mulberry leaves to pervade the house. Do not let me near your microwave.

Still, I was able to salvage some prepared food from the mess and transferred the babies to their first growing container with a cotton bud. They're eating their first meal now.