Wednesday 30 November 2016

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 ...

 

Sunday 27 November 2016

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.

Sunday 20 November 2016

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
 
 

Thursday 17 November 2016

Silkworms and Silkmoths?



Just to clarify matters, the silkworm is not a worm, but a caterpillar  - as a biologist, I consider these to be two very different creatures!  Most of the world’s silk comes from the domesticated mulberry silkworm, Bombyx mori.  This species has been selectively bred for around 5000 years and produces large, white, silken cocoons in which to pupate.  The caterpillar is an eating machine, not inclined to wander far, and although the caterpillars get quite large, most of their bulk is turned into that amazing silk cocoon, and the moth that emerges (if it gets the chance) is relatively small, quite plain and, although it has wings, it cannot fly. 
 
 

Silkmoth usually refers to a moth that is in the Saturniidae family - this is a pretty extensive family of moths, with examples in most countries worldwide.  All of them are quite big - some are huge, and most are tropical.  Confusingly, not all of them actually make silken cocoons, and where they do, the silk produced by the different species can vary considerably in quality and usefulness.   A lot of people breed these moths because they are absolutely stunning, and the caterpillars are often equally fantastic, so if they also produce useable silk, it’s an added bonus!
 

 Wild silk refers to the silk produced from any lepidoptera (ie a butterfly or moth) other than Bombyx mori and most wild silk comes from members of the Saturniidae family.  There are a few of them that are reared commercially and spinners will be familiar with tussah silk, which comes from Antheraea mylitta or sometimes from  the closely related Antheraea pernyi or Antheraea yamamai.    Wild silk does tend to suggest that these creatures are living wild and free, with their silk cocoons harvested from the forest - sad to say, I think this is probably pretty rare ....

Monday 14 November 2016

Where did it all begin?



For me, it started with the silkmoths.  Now I know that lots of people think moths are small, nondescript creatures that fly at night, but those people have obviously never seen tropical silkmoths!  My husband has been breeding these since he was a child, and so I have had plenty of opportunities to learn first hand about feeding, rearing and breeding them.  I still feel privileged when I get the chance to watch one of these small creatures emerging from its cocoon , to climb up and hang with shrivelled wings, slowly pumping them up to their full glory.  Of course, it’s not without its frustrations  - whether trying to find a suitable local substitute for some obscure tropical foodplant that will be acceptable to a fussy caterpillar or trying to persuade a female moth to emerge from her cocoon before the last male moth decides to die.  Over the years I have become familiar with the caterpillars and moths of a number of species, and found some of them in the wild in remote corners of the world, but more on that another time.

The spinning part came rather later.  After moving to Wales and being surrounded by sheep, I decided to learn to spin.  There seemed a certain romance about sitting at a spinning wheel turning fleece into yarn on a cold, dark winter’s evening, and so I bought myself a wheel - a secondhand Haldane purchased from Ebay.  I now cringe at the thought of what I could have ended up with, because this really isn’t the way to do things, but I was luck that my wheel was in working order, with all parts intact (and yes, it really was luck, and not judgement, on my part!).  So, with lots of practice and with the help of my local Guild, I have mastered the basics and can now produce some passable yarn from raw sheep fleece.


 

 
What to spin next?  Well, with an array of cocoons from various species of silkmoth, as well as some from the silkworms I reared last year, it was time to make silk .....

And so, two worlds collide -  the exotic moth breeder and the fibre spinner.