The Miracle of Emergence

My Madagascan Moon Moths (Argema mittrei) have begun emerging.  Its an exciting moment when you realise the process is underway and you get the chance to witness the sequence of events as it happens.  For those of you who have never had the chance to see this, we managed to get the camera set up and did a bit of time lapse photography, so here goes ...

 

The sequence starts after the moth has emerged from the cocoon - it will climb to try and get in a suitable space where it can hang downwards.  This one is hanging from a cocoon (you might notice its not a moon moth cocoon, this is an Atlas cocoon that was hung up in the emerging cage).  The wings are really shrivelled to begin with, and very soft.  They can be easily damaged at this stage.  The moth pumps fluid into the veins and the wings will start to unfold and expand.



Here you can see the forewings and the hindwings expanding.  You can start to see the long tails becoming visible too.

 

Once the wings are pretty much full size, the tails really start to lengthen.  You can't quite believe how long those tails are going to become when you see it at this point.

  

Those tails just seem to keep growing and lengthening ....



I thought the camera was adjusted to the right distance, but those tails are so long, we had to pull back a little further to fit them in to the shot!



So there's the final side view, and just one more front view to show the moth fully emerged.  This one is a male - the females have shorter tails and less feathery antennae.


 

The process you can see here took around an hour in total.  Emergence can be a lot quicker in other moths, but those tails take a little while to fully extend.  The moths usually emerge in the morning and then sit quiet for the rest of the day, so that the wings have time to harden before evening, when they may well become active and start flying.

There are a lot of things that can go wrong and result in a moth with stunted, shrivelled or deformed wings - it can be due to the caterpillars being inbred or just not very healthy, eating bad quality food, or some disturbance at a crucial stage of its development whilst inside the cocoon, or being too cold or too dry at the point when it begins the process of emergence.  Knowing all the things that can potentially go wrong, makes it all the more satisfying to see the process when it goes right. 

Now, if one of those female mittrei would emerge, there might be a chance of pairing them!!

Eri Silk, Part 2

So my wet mass of silk fibres has dried, and with a little teasing out, it looks a lot better than it did last night.





















In amongst the fibres, there are some of the innermost layer of the cocoons still visible.  These don't always degum very well, they feel very papery.  I usually take the larger bits out during the process of carding - here are the fibres ready to card.



























And here is what they look like after carding.






















There are some nice long, silky fibres combed out, but lots of bits too - if I had more of the fibre, I could pull out the smoother, silky pieces and spin them up separately to produce a finer and more even yarn, but there's not that much fibre, so I don't want to waste it.  I'm going to spin the lot, so it will be a bit uneven and slubby.  That's what we call a textured yarn!  I decided to spin it on the hand spinner as there is only a small amount.  Here is the completed spun thread.


 

The next step is to ply it - I did this by cutting the thread in half and twisting the two strands together,  Plying makes the yarn stronger and evens it out a bit too.  So here is my finished yarn.  Its turned out a nice ivory colour, but silk takes up dyes really well so I'm not sure yet what this will end up as.  Its not a huge amount, but its not bad from just 14 cocoons.

Making Eri Silk

I decided today to process the cocoons of my Samia ricini x walkeri.  There are not that many of them, but they range in colour from bright white, through beige, to golden orange.  I really like the golden orange ones, but I wasn’t sure whether that colour would remain in the silk.  In some of the silkworm varieties with bright yellow cocoons, they still produce white silk, because the colour is in the sericin (the glue that holds the cocoon together) rather than in the silk filament.

 Here's what I'm starting with.

 

The first step is to clean out the cocoons.  Although the moths have emerged, this doesn't mean the cocoon is empty.  Inside is the shed skin of the caterpillar, and the empty pupal case.  Its a bit fiddly opening up the cocoons and removing all the detritus, but if you leave it in, then you end up picking bits out of the silk all the way through the process, so the cleaner the cocoons are at the beginning, the better. You can see some of what I’ve removed in this picture.

 

It doesn't really matter if you cut open the cocoons to remove the bits inside, because its not essential to keep the fibres unbroken.  I start the process of making the silk by putting the cleaned cocoons into a saucepan of hot water, with a bit of stergene and washing soda added.  I then push the cocoons under the water to get them really wet, bring the water to the boil and simmer very gently.  Some people say you shouldn’t boil the silk, but especially with the wild silk, nothing much seems to happen if the water doesn’t get sufficiently hot.   

 

 

The cocoons will start to soften and loosen, and if you push a kebab stick in, you can see the fibres unravelling and the cocoons breaking down into a mass of threads.

 

When they get to this stage, I rinse them out in warm water to get rid of the soap and washing soda, then give them a final rinse in some water with citric acid added to it (or you can use vinegar instead)- this is to neutralise the alkalinity of any washing soda that might be left behind.   At this point, it looks and feels really soft and,  well ... silky!

 

After rinsing, I squeeze the excess water out and leave it to dry.  It doesn’t look quite so appealing at this stage.  I am a little disappointed that I have lost that really bright orange colour -  its mostly a mix of pale gold, ivory and white.  

I am going to leave it now to thoroughly dry out, before moving on to the next stage, turning it into carded fibres and silk thread.

The most stunning silkmoth?

The postman brought me a great parcel today, it contained ten cocoons of the Madagascan Moon Moth, Argema mittrei.   The cocoons are silvery and netted, really pretty.  These ones have been cut open to check the pupae inside.  If you know what to look for, you can see not just if the pupae are alive and healthy, but also whether they are male or female, and whether they are close to emergence. 

 

There are four males and six females in my batch -  this pupae is a female.You can see the body of the moth, the feathery antennae curving downwards and the shape of the wings that are crumpled up inside there.

 

It may not be too long before some of these emerge, but in the meantime, here’s a photo of a male moth from a couple of months ago.  Its on my daughter’s hand, so you can get an idea of the scale.   

 

They are the most amazing and gorgeous creatures.  We managed to see these in the wild in Madagascar a few years ago.  As far as I know, the cocoons are not known to have ever been used to produce silk in Madagascar, but if you process the cocoons, it certainly looks like useable fibre.  Its a lot thicker and coarser than some of the other silks, but now I have a few more cocoons, I will have a go at spinning it up when they become vacant.

 

They don’t use the Argema silk in Madagascar, but I have since found out that there is another moth native to the island that has been used for silk production.  Its not a Saturnid, but a member of a different family, the Lasiocampidae.  When I looked up Borocera cajani online to find out what it looked like,  the caterpillar sounded very familiar and here’s my photo of it  - I didn’t realise at the time the significance of this caterpillar.   

Its very well camouflaged, but when disturbed, out come these four big, orange tufts of stinging hair.  In some parts of Madagascar, they are trying to reforest upland areas with native plants, including the foodplant for this caterpillar.  Harvesting the cocoons and turning the silk into scarves is making a real difference to the lives of the women of the villages involved in this conservation project.  They are getting the opportunity to earn an income sustainably, whilst improving native habitat.  If you are interested, take a look at the video at  www.feedbackmadagascar..org/eng/whatwedo/projects/proj_silk.php.  I’d love to go and see this for myself and find out about it firsthand.

And more moths ...

I still have a few caterpillars from my second lot of Samia of unknown race (possibly Samia wangi).  The remaining caterpillars are pretty big and it shouldn’t be long before they are ready to pupate.  The colours on them are fantastic.

 

Most have spun up already and I have a nice batch of cocoons.  I was wondering if they would go into diapause and I could have a break until the weather warms up and the vegetation starts growing again.  With the recent cold weather we have had, the privet really isn't the best and that has to have an effect on the health of the caterpillars.

But no, this morning I had a newly emerged female moth.  She is very pretty -  I’m guessing it may not be long before I have a male to join her.  I already have eggs from the ricini x walkeri batch.  Looks like I will be having a busy time again soon.  The good news is I won’t have to wait too long to process that silk ....

  

Moths

Well the question has been answered.  At least some of my pupae are definitely not in diapause: they have begun emerging, and they are wasting no time in finding a mate!  Within hours of emergence, these two have paired.  They will live only a week or so as a moth, so they have to be quick.  

 

You can tell the difference between the males and females fairly easily, especially when you have examples of both to compare.  The female’s body is much larger than the males, as you can see here.   

 

She is already full of eggs and once mated, she will start laying very soon after.   The faces of moths are much prettier than that of butterflies, and here is another way to tell male and female apart  - take a look at their antennae.   The female has long, feathered antennae.

 

  

But the male has wider and even more feathered antennae.

He uses these to smell -  there are a huge number of olfactory receptors in their antennae and this enables them to detect the pheromones emitted by a female from a great distance and to pinpoint her location very accurately.  That’s not really a problem for my moths ...

 

When will my moths emerge?

Apparently one of the most frequently asked questions when breeding silkmoths.  It is also one of the most difficult to answer.

In most parts of the world, apart from the wet tropics, a caterpillar’s food plant is actively growing and available for only part of the year.  As a result, many species of butterfly and moth have needed to develop some strategy to avoid having their caterpillars hatch in the middle of winter, or during a long, dry season.  One of the ways they can do this is for the pupae to go into diapause -  its a dormant stage, a bit like hibernation. 

So here is the dilemma with my  Samia cocoons  -  they are a cross between ricini and walkeri.  Now walkeri is the race that has been introduced into Italy and parts of the USA, and has successfully managed to survive in the wild there for many, many years.  It is able to do this because the pupae go into diapause and remain inside the cocoon over the winter, only completing their development and emerging when spring temperatures are warm enough.   But that’s not the whole story, because some moths are multibrooded - if the growing season is a long one, then the first batch of caterpillars produced might pupate quite early in the summer, and instead of going into diapause, the moths might emerge within a couple of weeks and produce a second generation of caterpillars that will pupate at the end of the summer, with these later individuals overwintering.   So walkeri pupae might go into diapause, but ricini are very different. 

Samia ricini are tropical and their life cycle is a continuous one, going from egg to caterpillar, to pupae, to moth, then pairing, laying eggs and the whole process continues.  It doesn’t give you much of a break when you are rearing them  -  in reality, by the time the last caterpillar has pupated, the first moths may well be emerging, ready to pair and lay eggs that will hatch a couple of weeks later.  It can become a bit of a chore and more than a little inconvenient if you want to go on holiday  - have you ever tried to get a petsitter for your caterpillars?

So there you are, when will my moths emerge?  Will they go into diapause?  Its just a matter of wait and see for now.  They are in the emerging cage, keeping warm for the moment.

 

I have some different cocoons that are in diapause.  These ones are Antheraea mylitta, the Tussah Silkmoth, producer of tussah silk.

 

These are tropical moths so they don’t want a cold winter, they are instead going through their dry season.  I am keeping them at room temperature, and then if all goes according to plan, in the spring I will put them somewhere warmer, in an enclosed cage with damp moss on the bottom, and mist them.  As long as it stays warm and humid, this will mimic monsoon conditions and encourage them to emerge.  Timing is important though, because once they emerge and pair, the eggs that they lay will hatch in another couple of weeks and by that time, I will need to have a supply of fresh oak leaves for the caterpillars to eat. 

 

The cocoons of mylitta are quite big, and they are really hard.  Its quite hard to believe that they will really break down into a mass of soft, silky fibres.    

With some cocoons it is possible to carefully cut them open and look at the pupae to check that they are still alive, and whether they are in diapause or forming up ready to emerge.  Its not recommended with these cocoons though, its too likely that you would damage the pupae by trying to open them, as well as making it very difficult for the moth to successfully emerge from the cocoon later on.  I am hoping that these are all still alive and will emerge at the right time, but there is never a guarantee.

Lots of Hungry Caterpillars

I have a few boxfuls of caterpillars at the moment, all busy eating and needing regular attention.   They are two types of Samia.  So time for a little bit of history - Samia cynthia is a species of silkmoth from China and Korea originally.  As a result of being used for silk production, they have been introduced to lots of different parts of the world and there are sufficient variations for them to be recognised as distinct races, but  they are still all the same species (unless someone has decided differently since I last checked, which is quite possible).  Ricini is the tropical form that is reared in India for eri silk.  I had some of these a couple of years ago and they produced big, fluffy, white cocoons. 

So, the first lot of caterpillars I am rearing this time are a cross between ricini and walkerii, which is the form that was introduced into Italy and now lives wild in some areas.  Most of  these caterpillars have already spun their cocoons, and they are a fantastic mixture of white, pale gold and bright golden orange in colour.  I am looking forward to seeing the moths when they emerge, because I got these as eggs. 

 

 

The other caterpillars I have originate from some Samia cocoons I got at around the same time.  I don’t know which race these are, but the cocoons are quite different, much smaller and tighter, and beige in colour.    Here they are pictured with some of my old ricini cocoons.

 

 The moths that emerged from these cocoons were really brightly coloured and laid lots of eggs, hence the hungry caterpillars.

The caterpillars are gregarious when they are small and all sit together on the underside of the leaves.  I am feeding them on privet, because as its winter there isn’t anything else in leaf that they will eat.  Here they are at different stages in their life cycle. 

 

 This one has just shed its skin, you can see the old skin stuck to the leaf behind it

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 Here's what they look like when they are full size caterpillars, with a hand behind for scale!

They are very colourful at this stage.

 

 And here, one has just started to spin its cocoon.  It takes a few hours to complete the process.

 

 

 

Although the cocoons don’t look very substantial, I have processed the eight empty ones I have so far.  After carding the fibre, it really looks quite pretty.  I am looking forward to getting enough to spin a reasonable amount of yarn