Sunday, August 10, 2014

Silence of the Lambs and Out of Africa?

At the end of my penultimate update  I posed a question about the identity of the eggs in my photographs. This latest update will deal with one of those photos; why just one? Well because, as I write, nothing has yet emerged from the eggs in the second photograph, that will have to wait a little longer.

This then is the story of the little cluster of pale eggs in the second photo, that looked like this:



I would be surprised if anyone has been able to guess the identity of these as they are in fact a migrant species and can also be found throughout tropical Africa. 

The death's head hawkmoth (Acherontia atropos) is one of the UK's largest moths. The life-cycle has 4 stages: Egg, larva, pupa and adult. The eggs are pictured above and the first instar larvae look like this...


As they increase in size, they become greener...


The caterpillars are not very active and seem to move only when they need to get to another leaf, having eaten the one they are on. In the 2nd instar stage, the horn begins to shorten and turn yellow.  The body and horn become covered in minute pale tubercles...


By the time of the 3rd instar, the 7 lateral stripes are fully developed and are blue edged with white. The tubercles are now enlarged. This is a typical pose for the early instars, along the vein, underneath a leaf. As they grow they become too large to do this and have to rest on a leaf stalk or branch.




Here's a short video of one feeding (the usual reminder about needing to view directly from my blog to see videos, the e.mailed version won't show)...

video



Instar 4 sees the yellow tone becoming more vivid and the horn recurves further...


The 5th instar is the final one before pupating-here's a freshly moulted one...


Now the tubercles are lost apart from the horn, which is strongly recurved. The blue edge of the lateral stripes becomes more extensive forming a series of broad, V'shaped bands along the back...


The final instar larvae are huge; I measured one at 100mm and it was still growing. They consume an enormous amount of the food-plant (in this case privet) at this stage as well.

When they are fully grown they darken a little and begin to cover themselves with a saliva-like secretion just prior to pupating. The next video shows this but I've increased the speed to keep the size reasonable for the blog...and your patience...





It then wanders away from the food-plant and pupates by burrowing into the soil...






The video above actually show the largest of the larvae I have, starting the pupating process. I originally had 15 eggs, from which only 4 larvae emerged. I'm not sure if this is normal but somebody else did tell me that they had 15 also and only had 5 larvae. Right from the start I have been amazed at how the growth rate has differed. These all emerged the same day and withing a fairly short space of time and yet.....well here's a photo that demonstrates the differences...



The larger of the two here appears to be two instars ahead of the smaller one. And so now I have three more yet to pupate and I am wondering if they will then over-winter before the moths emerge. My friend Su Reed who also had some of these said that hers emerged after around 4-5 weeks but I guess it may be getting too late in the year for mine. Either way, that will be quite an exciting time as the moths are huge and squeak!




It would be remiss of me when talking about these mystical moths to not mention that iconic film poster. As any film buff will gladly tell you (something I am not by the way) the poster shows Jodi Foster's face with a large moth placed over her mouth. That film being of course, 'Silence of the Lambs'. This is supposedly the 'Death's head' moth from the film...


But if you take a closer look at the ambiguous skull in the image, you'll find it has been manipulated and actually comprises seven, female naked bodies....


The image originated in a photographic portrait of the artist Salvador Dali and this photo itself was inspired by surrealist Dali's gouache 'Female bodies as a skull' painting.

The true 'skull' on the moth should look more like this...


That then is the story to date and I will be watching for any moths that might emerge later in the year, failing that, next spring. Whenever it is, there will be images here for sure.

That's about all for this update, I hope to have news of the other eggs sometimes very soon, until the next time...


14 comments:

  1. Nice to see on a rainy morning

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  2. I recently discovered your blog through a google search for some insect (can't remember which now!). This post was very interesting - I like seeing all the instar stages of insects. I've never tried hatching moth eggs and watching the caterpillars, but I'd love to do it! I'm a bit put off by the responsibility though, and the fear of not providing enough food or whatever! Anyway, very interesting blog, will follow :)

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    1. Thanks for your interest Louise. Yes, the food is very important for caterpillars, after all they are basically eating machines. Just overnight without food could be enough to see them fail, but it's not difficult to ensure they have plenty.The rewards are plentiful too, I have learned so much about them and their life-cycle from observing in this way.

      I look forward to taking a look at your own blog sometime soon.
      Regards
      JJ.

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  3. Wow! A moth! And what a moth it is! Suppose being bug-brained I never thought about the eggs being a different family! The caterpillars are fantastic and it's fascinating being able to see how they develop and progress through the different instars! Brilliant!

    Interesting info on the Silence of the lambs poster too! Had never looked at it that closely!

    Maria

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  4. Hi Maria,
    Thanks for your lovely comments here. Yes, these are big larvae but fascinating too. I am hoping that when the moths emerge, I will be lucky enough to have both sexes.

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  5. So many different beautiful colours for same caterpillar! Very beautiful! Thanks for sharing.

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  6. Oh. My. God. !!!!! How on earth did you find those eggs and more importantly, how did you know what they were - or did you just decide to raise them and see what hatched out? What an absolutely magnificent creature this is in larval form. Each instar is just amazing!

    I've just had a read about it and see they lay eggs on potato leaves - well mine have been chopped back because they were blighted but it also likes physalis which I have lots of! I will have to go and look!!

    Apologies for all the exclamation marks but this is just incredible and I'm dead jealous. :-) Also interesting titbit about the image on the film poster.

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    1. Thanks for your great commenting Mandy. I have mailed you a full reply.

      Regards
      JJ.

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    2. BTW...if anybody knows why my replies keep appearing in these annoying grey boxes, please do let me know!

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    3. No idea, I haven't seen that before!

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    4. Ooooh! Now you're in the grey as well Mandy!

      I have no idea about this-it only happens if I use the 'reply' option. If I add a fresh comment, it doesn't appear. I have Googlyoogled it but couldn't find a resolution. Might have to ask Blogger direct? I notice it isn't happening on your Blogger pages...

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    5. It may just be the way it is on the template you are using. I don't think it is annoying and possibly it's used to make the reply stand out more? I shouldn't worry about it. :-)

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    6. Just thought I'd extend this lovely grey a little more! ;-)

      Thanks for your interest Mandy. Yes, I get why it's probably done but if it's just a part of the template, I can't understand how it has only just started to show, unless they have made alterations in Blogger? Anyhow, as you say it isn't really important ;-)

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Regards 'JJ'.

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Thank-you
JJ.