Thursday, February 19, 2009

Silkworm cycles

Yesterday, at dawn, my last silkworm emerged from her cocoon and promptly started to mate. This morning she has laid some eggs. I have a feeling this may be the last clutch. Other matings seemed to have yielded no eggs at all. I think maybe these held on to each other too long because now they seem to be almost dead with exhaustion.

These are all that are left. The majority have died. They seem to die gently and gradually, life slowly leaving them, and I pick them out and place them alongside the cocoon. How shrivelled and small they seem to be now. All that huge consumption of mulberry leaf extract has led to is this.

And this.

Where does it go? I think the answer must be into the air: starches converted to sugars in the gut of the silkworm and then stored as fat, must eventually be consumed in the business of mating to produce energy and carbon dioxide and water...which the mulberry bush could one day use again to produce more leaf. It is a pretty cycle.

In some parts of china the silkworm-mulberry plantation, together with a fish pond, provide a self-contained ecosystem for a small community. The silkworm feeds on the mulberry and produces cocoons. Its waste is fed to the fish; white the pupa provide useful nourishment to the growers. The sludge from the fishpond is used to fertilise the mulberry plants, and the fish themselves are another source of food. I like the way nothing is allowed to go to waste. An extension of this idea - the use of silkworms as a useful food for astronauts - is reported in March's edition of Scientific American. Pupa not only contain fat, but four times as much protein as eggs and milk. Also 'These insects breed quickly, require little space, food or water, and produce only minute amounts of excrement, which could serve as fertilizer for onboard plants.'

I am not so sure about 'little food' - but I suppose in comparison with most mammals and birds silk worms are indeed very efficient converters of plant into animal.

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Blogger BarbaraS said...

This is why I read this blog; it's not just about what the silkworms turned into, it's what it all means :)

Thu Feb 19, 09:59:00 am  
Blogger Clare Dudman said...

Thanks Barbara - heh, what I think it means...

Thu Feb 19, 10:39:00 am  
Blogger Ian said...

Silkworm cocoons are a popular snack in Korea. Personally, I found them a bit too musty for my taste.

Fri Feb 20, 11:39:00 am  
Blogger jem said...

I still those those eggs are beautiful. The other day I got mosaic, today it's braille - I wonder what message they are spelling out.

Fri Feb 20, 11:49:00 am  
Blogger Clare Dudman said...

Yes! Braille is good, very good - so many meanings!

Fri Feb 20, 11:55:00 am  
Blogger Clare Dudman said...

Sorry Ian, I didn't notice your comment until now - something wrong with blogger, I think. 'Musty' eh, now that's interesting. Do they eat the whole cocoon or just the pupa? I've heard that in China children prefer the pupa to chocolate.

Fri Feb 20, 12:46:00 pm  
Blogger Ian said...

I only ate one the whole year that I lived in Korea, so I'm not an expert. One was enough. It had been dried/cooked in some way so it was a bit crunchy. They sold them in the markets and also had them as bar snacks. I don't know how they can enjoy eating them. Personally, I much prefer snakes, frogs and snails.

Fri Feb 20, 01:00:00 pm  
Blogger Clare Dudman said...

You eat snails, Ian? I am shocked. :)

Fri Feb 20, 01:04:00 pm  

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