Thursday, September 29, 2011

Do Butterflies remember being Caterpillars?

Commitments and circumstances have conspired to keep me away from 'blogging' for, well too long really. But, as John Lennon famously said "Life's what happens whilst you're busy making other plans" I may have paraphrased him there but it was something very similar anyhow.


I mentioned in an earlier posting that I had some comma butterfly larvae that I was rearing and that I would do an update on their progress. This blog entry will attempt to fill you in on everything that's happened in the past few weeks concerning the little beasties.


It was late August when I acquired the larvae (Caterpillars) and at that stage, I would guess they were probably only first or second instars and no more than a few millimetres in length.


I collected lots of Hop, one of their favourite food-plants and they seemed happy enough and soon grew to a respectable size and with each moult, became more elaborately coloured.


Click on any photo for a larger view



By the time September arrived, they were pretty much fully grown at about 35mm.


I had noticed that although these were all from the same batch of eggs, they progressed at very different rates and some seemed almost ready to pupate at the same time as others were not even to the stage of a final moult. When I say, final moult, I am discounting the fact that the act of pupation is in itself a 'moult' and therefore should really be considered as the last one.


The first signs of imminent pupation in the larger caterpillars was when I observed a real increase in food intake. They seemed to be getting through the hops at an alarming rate and even worse, the evidence was there for all to see (and me to clear up) from the other end of the larva!


On September 7th, the first one left the area where it had been feeding for the past weeks and climbed to a stem some way above the leaves and attached itself by the 'Cremaster' (a cluster of minute hooks) in the classic, head-down position.



It remained in this position, motionless, apart from the odd twitch for sometime. On the following day at around 2pm it began to twitch again and the pupation proper had begun. I suppose it was around 26 hours from the first signs to the completion of the process.


video
This is around 10x faster than actual speed.



The body that's revealed when the caterpillar sheds it's skin for the last time, is the pupa or chrysalis. It no longer feeds of course but will still twitch in response to threats but is otherwise 'sessile'.
At first it's soft and skin-like but soon hardens and it's this shell that protects the butterfly whilst it transforms.


This stage lasts around 2 weeks for the comma butterfly but can vary greatly for other species. The pupa is light in colour at first...



        ... but darkens over time until it looks like this 



I won't go into the whole business of just what happens in complete metamorphosis because I touched on it in an earlier posting, but the complete transformation is known as 'Holometabolism' and I've heard it described as a kind of re-cycling! It's not the worst analogy I've heard. If you drop a plastic bottle into a re-cycling bin, it gets melted down and reformed as an entirely different shape.That's close to what's happening here.


The next stage to look out for as an indicator of the final steps towards emergence is a change in colour from the dark. almost black that they've acquired, to something that at last seems to reveal the amazing process that been happening, unseen for the past 2 weeks or so; the very clear sighting of the colours of the adult comma butterfly wings that are now showing through the walls of the pupa.
Confirmation that the journey is almost complete. This is what it's all been building to, the final countdown has begun! Nature is about to dumbfound me yet again.


The little video that follows, although isn't the best quality or colour, and does have some very 'rural' editing (I don't have great software for editing movies is my excuse), but is never the less the result of many hours spent caring for and observing these insects and what it shows is something that few have been privileged to witness.


Complete metamorphosis is nature at it's wide-eyed,gob-smacking, amazing best! Not very literary, I agree but sometimes less is more?


And so it was that 17 days after the first larva became a pupa/chrysalis and just 7 days following the final larva's pupation, I was lucky enough to be there and watch in awe as a beautiful comma butterfly made it's entrance...


video

I wish that I could find a way to share this as the HD-Movie that it was videoed in but I've had to reduce both size and quality to get it to display here. I intend to work on this for future videos and if anyone knows of a way to display them at a larger size/quality, I'd be happy to hear from you.

I was on a high for sometime having watched this action and leaving aside the complete joy at witnessing it, I have learned so much at the same time.

It had no idea for instance that the pupal shell is forced open by the butterfly using its feet. The wings were wrapped around the insect, again, I had no inclining that was the case.
What struck me above all else though, was the proboscis; it seemed  to be 'unfurled' and stretched the length of the body. Only when the butterfly had struggled free of the shell did it then recoil like a spring.

Some recent studies have shown it may be possible that butterflies can remember some of their lives as caterpillars.

When caterpillars were conditioned to avoid specific smells (did you know caterpillars could smell?) they seemed to remember to keep away from those scents as adults.


Meconium

During the emergence of the butterfly from the pupa, there is a substance secreted that looks for all the world as if it is blood. It isn't and there's no cause for alarm.



  • In biology, meconium describes the metabolic waste product from the pupal stage of an insect that is expelled through the anal opening of the adult upon eclosion from the pupa


  • Adult Butterflies are not able to fly until their wings gain blood circulation and completely unfold; this usually takes 1-3 hours depending on the type of butterfly and of course, at this stage they are very vulnerable.


    I took lots of photographs of the adult butterflies before releasing them in local woods. It was great to feel that I was doing something to help protect and conserve the population, especially in light of the fact that this year was particularly poor locally for commas. The weather has been superb for late insects and I'm sure they'll feed-up on whatever they can find before hibernating through the winter to emerge as breeding insects next spring.


    I'll add some more pictures in my next posting, but for now here's one of the adult that I followed right through from caterpillar to adult butterfly.


    Until the next time then...


    Comma Butterfly (Polygonia c-album)





































    Wednesday, September 07, 2011

    If the rain comes they run and hide their heads...

    I cribbed the blog title of course from what has been called The Beatles' finest B-side. It's the first line of the song 'Rain' for anyone who doesn't know it (Shame on you).


    It seemed apt as the weather here in darkest Kent U.K. over the past few days has been just that. 
    "Run and hide their heads" however, is less pertinent because I wanted to feature a Horsefly that was doing just the opposite one morning when I went out on my early (and rainy) walk.


    It was sitting in the open and was either cold due to the time of day and inclement weather, or, had been asleep.
    These big flies have fantastic eyes but the females are known to administer a very painful bite-and so it's not too often that I get a chance to photograph one that seems docile and poses little threat (hopefully).


    I've also been toying with the idea of doing some 'image-stacking' for sometime and thought this'd make for a superb subject.


    I had the 100mm macro lens on the camera and just to make things even more difficult (macro can be taxing at the best of times, throw in low light levels and it becomes even harder to obtain decent images), I found the  Raynox DCR-250 in my camera bag and added that to the macro to increase magnification. No tripod or monopod and so hand-held was the only real option. The insect was too high up to kneel down or brace myself against anything. I took this first shot.


    Click on any picture for an enlarged version.




    This was just a single frame/exposure and although the light isn't brilliant, or all that even, for a dull and rainy morning it could be worse!
    I took a few more similar photographs and then had the bright idea (no pun intended) of enhancing the light by holding a small, makeshift reflector underneath the insect; or at least, as far underneath the insect as it would allow without wanting to annoy her!


    This second photo is the result of that-as you can see, there's not too much difference other than the reflector was in shot, hence the lighter background to this shot. It has removed some of the darker areas at the bottom of the eyes to be fair; trying to balance everything wasn't fun though..




    Image stacking for macro purposes can be used as a tool to increase depth of field; a problem that we all suffer from. That is, by being so close to the subject being photographed, there is very little depth of field. Hence, almost inevitably, some part of the image will be out of focus.


    To try and overcome this problem, it's possible with digital photography to take a whole series of shots from a single position focusing on a different part of the subject with each fresh exposure. Perhaps, closest to the camera for the first shot ending up with the last frame being farthest from the camera.


    Then using software, the images are combined, or 'stacked' in order to form one final photograph that should have everything in focus. Well that's the (simplified) theory! Depending on which software is chosen for the job, it can be a little forgiving of any slight movement but really it's a sturdy tripod and focusing-rail job for best results.


    I've already mentioned I didn't have a tripod with me (in fact, I don't even own a decent one!) and so my only choice was to try a hand-held series of shots. I've seen some photos done this way and it can be achieved, armed with some previous advice from a 'flickr' contact (you know who you are) I tried for a series of around 8-10 shots. As far as I could tell by reviewing them on the camera's screen, they didn't seem too far off the mark.


    WRONG!  Well I know now that I've tried to stack those images that they weren't good enough for several reasons. It seems to me looking at the resulting photograph that the main one is the lack of good lighting that has culminated in a lot of 'noise' spoiling the image. Possibly the alignment isn't actually all that bad for a first attempt?


    8 image stack
    Whilst there is quite a lot more of the image in focus, more frames would have made such a difference. I'm not even sure that the detail is that much better either than the photo below that is a straight crop from a single-exposure photo taken at the same time?


    Cropped from a single exposure


    However, hindsight is a wonderful thing and at the time I felt it was worth a shot at say, 30 frames to try and get a nice, smooth transition between shots. I braced my arms tightly to my sides and got into position, all the time the rain was still falling, agreed, not as hard now but just to make me feel a complete idiot for even attempting photography in these conditions, the wind began to howl too. If this is beginning to sound like a poor excuse for a poor result, you could be right but what the hell; in for a penny in for a pound as the old saying goes.


    I managed 27 shots before giving in to the conditions and my aching arms. Once again I reviewed my handy-work on the camera's screen.
    Hmmm.... looked reasonable but then how often have I thought the very same thought, only to get home, download the images and view them on the P.C. only to be disappointed?


    The software and my ageing P.C. took quite a while to process the 27 images and even before  I had loaded them I realised that the chances of an acceptable resulting picture at the end of it all was, well, let's say less than certain. 



    Admittedly I only have free software for this operation and there are (much) better programmes available but even if I had available funds, I wouldn't want to invest in something until I knew that stacking would be something I'd take to and do on a regular basis. Moreover, even the best software is unable to cope with my amateur attempts at providing sensible raw materials to work with.


    And so here it is then, my hugely disappointing first real attempt at a 'proper' stack! 




    As you can see, the lighting is awful and one-sided, the frames aren't aligned correctly and the whole thing looks a bit of a mess. By the way, I didn't use the full 27 shots in the end.
    As usual I had jumped in at the deep end before learning to swim. What have I learned? Well, not to be so adventurous in future. Get back to basics before attempting anything as ridiculous as this again and try not to ignore the basic rules of image stacking. 



    I share this with you all in the hope that it will prompt anyone with greater knowledge than I (stop it) to offer advice/solutions and general criticism to aid any further excursions into 'stack-land'. 



    Until the next time then...























    Monday, September 05, 2011

    To everything- turn, turn, turn...

    As summer eases itself into autumn/fall, things are beginning to change. The days are shortening, at least the amount of light each day is a little less. The hedgerows are alive with berries and fruits and the green of high-summer that blanketed the countryside is starting to fade.

    All is not lost though, for associated with the loss of the emeralds comes all manner of delights that will soon form a new canvas to be admired; and what a palette it'll be.

    CLICK ON ANY IMAGE FOR A LARGER VERSION

    Rain on autumnal leaf.

    I didn't plan to get all poetic there! I do love the autumn months though; frosty mornings, spiders webs hung with dew, the patterns of warm breath as it meets with the cold air. Crisp, fallen leaves underfoot, the riot of colour amongst the ancient woodland trees. shafts of sunlight through increasingly bare branches, fungi, fabulous sunsets.....

    Setting sun behind Union Mill at Cranbrook.

    Sunset-complete with mini-whirlwind.

    Autumn skies

    The changing season hasn't adversely affected the bug-hunting (yet) in fact, the first few days of September have been quite productive.
    As I'd hoped, the numbers of dragonfly have increased dramatically with more sightings locally over the past weekend than probably the rest of the summer.
    Mostly Common Darters it has to be said but there are a few of the larger Hawkers getting about now and even one or two Emeralds.

     Common Darter Dragonfly

    Some of the shield-bugs that I've been seeing as nymphs I'm now sighting as adults. A few of them will soon be changing colour too as they acquire their winter coats. The Forest Bug (Pentatoma rufipes) that is a fairly common bug that can be seen locally on many deciduous trees, will probably be with us feeding on fruit and any caterpillars it happens to find until it becomes dormant from November through to next spring.

    Pentatoma rufipes.

    Another interesting creature that, as its name would suggest, becomes prevalent at this time of year is the harvestman. Harvestman (Opiliones) are closely related to spiders; unlike spiders though, the do not have segmented bodies and cannot spin a web,
    It catches it's prey with hooks on the end of it's legs; it can also shed a leg to escape capture. They will eat small insects, snails and worms.

    Interestingly, fossils have been found in Scotland that are in excess of 400 million years old and they show that the basic structure of the harvestman has changed little.

     Harvestman
    There is no song associated with the oak bush-cricket but they are fully winged.The cricket is nocturnal and not usually to be seen in the daytime (although my photo was taken mid-morning) and becomes more active at night when it can be attracted to lights and even found in houses or under street lights.This bush-cricket is restricted to woodlands of all types and hedgerows although it may also be found on garden shrubs.


     Oak Bush-Cricket (male)

    The best time to spot these little crickets? From now until wintertime.

     

    Lastly for this blog entry; I'm raising some Comma Butterfly larvae that fingers crossed will pupate to emerge as adult insects that I'll then be able to release into local woods that have had a poor year for these striking butterflies. It'll be my small contribution to the local population for years to come if all goes to plan.

    I plan to update the blog on my efforts to raise these caterpillars but for now I'll leave you with this splash of colour that is a comma larva photographed on hop, with bright red geranium flowers forming the backdrop.

    Comma Butterfly larva.



    A Comma Butterfly



    Until the next time then...

    Footnote: I apologise if some of the text in this entry is poorly spaced, it is down to blogger and not me! I've tried to correct it but been unable to.