Thursday, 26 October 2017

Chinese Oaks Silkmoths Part 2

It was really good to get my caterpillars through to pupation, but I wasn’t sure how long it was going to be before the moths emerged.  It turned out that they went into diapause.  That wasn’t such a bad thing because I wanted to go away for a little while over the summer and whilst its not that hard to find someone to look after a cat or dog when you go on holiday, finding someone to look after your caterpillars is a little challenging!

As the summer wore on, the cocoons remained inactive.  I started misting them every day to increase the humidity, but still nothing.  In the end I had to put them in a plastic box with a shallow layer of water for a couple of days  - this was enough to fool them into thinking the monsoons had arrived, and soon after the pupae started to form up and I was really happy to see this.


Over the course of a few days, all the moths emerged and without much encouragement, they paired and laid eggs.  

I have no shortage of caterpillars now.  They are busy chomping their way through the oak leaves, which are rapidly losing their colour as autumn hits.  I am hoping to keep them going on the (just about) green oak leaves for as long as I can, but then they will have to start eating evergreen oak.  They don’t usually grow as big when fed on Holm Oak, but when you compare the tough, dry leaves with the lush new growth of the deciduous oak, its perhaps not a big surprise if its not as nutritious.  I will be very happy if I get these through to pupation and they go into diapause until the oak trees are back in leaf again. 

Chinese Oak Silkmoths

Antheraea pernyi are supposed to be one of the easiest silkmoths to rear, but I have had a few problems with them the past few times I have tried.  I think its because they are intensively reared in sterile conditions, with the use of antibiotics, to produce a type of tussah silk.  The caterpillars don’t develop a very strong immune system when they are raised in these conditions, and if you try to rear them at home, they don’t do very well.  Anyway when I saw some eggs being advertised for sale that were supposed to be from wild stock, I took a chance.  It turned out to be a good move.

The eggs hatched into tiny black caterpillars.  As the name suggests, they like oak.  They much their way through those leaves, shed their skins, carry on eating, and then at the next skin change, they turn bright green. 

They stay bright green for the rest of their life as a caterpillar, but get a lot bigger.  


That green doesn’t look like a great camouflage colour until you see them on some really fresh oak leaves, then you realise that they blend in very well indeed.

Every so often, they go quiet as they build up to shedding their skins.  Their new head grows behind the old one, and to shed their skin, they push off their old face and wriggle and pull themselves out of their old skin, leaving it behind fixed to the branch.  They don’t eat for a little while before shedding, so once they have gone through the process, they are pretty hungry.

Here’s one of my caterpillars just about full size, they really are quite impressive at this stage.  They are eating a lot now, because they won’t eat again once they are ready to spin their cocoons.  They need to consume enough food at this stage to produce silk, to give them the energy to pupate and then to emerge as a moth and survive for a couple of weeks, hopefully long enough to find a mate and produce the next generation.

Its very satisfying when you get to this stage -  freshly spun cocoons  - they are a beautiful pale gold colour and quite substantial.  Inside the caterpillar will shed its skin one final time and turn into a pupae.

Sunday, 8 October 2017

Madagascan moths

I love the caterpillars, so what about the moths that emerge.  Well, they certainly aren't a disappointment.  The males are more brightly coloured than the females, but both are pretty gorgeous creatures. 

Here's a close up view, sitting on a pile of cocoons in the emerging cage - and no, those are not Antherina cocoons.