Tuesday, December 27, 2011

Diary of a butterfly

Note: To all those who suffered the indignity of non-notification of new posts, followed by my attempts to notify you myself and then probably getting notification after all-I apologise and I am pretty sure I've fixed the problem now.

With British butterflies being in decline and 2011 not being a good year in general it was a real joy when out walking on April 7th to find my first Orange-tips (Anthocharis cardamines) a few females.

Orange-tips are a true sign of spring and one of the first species that does not overwinter as an adult to emerge.

These butterflies will use Cuckooflower (Cardamines pratensis) both as a nectar source and for egg-laying. I spotted the first Cuckooflower actually in-flower on March 20th, having already seen Violets and Wood sorrel.

On April 9th I saw my first  males. I had already come across Peacock, Comma and Speckled-wood butterflies by this time.

It's only the more-conspicuous male that has this orange tips to it's wings, with the female often being mistaken for one of the other 'whites' especially the small white.

The Orange-tip Butterfly (Anthocharis cardamines)

By as early as April 15th I was already finding eggs on the Cuckooflower. 2011 did produce an exceptional spring with some stunning temperatures and long-hot days, on the 7th for instance, I recorded 20 degrees.

When searching out suitable plants on which to lay her eggs, the female will initially locate a plant by sight before alighting on the plant and tasting it with her feet. If the plant is suitable, a single egg is laid on a flower stalk. Eggs are laid singly for good reason – the larvae are cannibalistic. As a result, it is uncommon to find more than one egg per plant and it is believed that the female is able to detect eggs that have already been laid.

The portion of text above in italics I gleaned from ukbutterflies.co.uk a great source of information, as with all literature on the subject though, it should be read as an overview and not a 'bible' as there will be deviations as in all of nature.

A recently laid Orange-tip ova
Eggs are a greenish-white when they are first laid, they then gradually turn yellow, to orange and then eventually colour-up further showing the larva colours,with the larvae emerging after anything between one and two weeks.
Interestingly, although according to U.K. Butterflies it is uncommon to find more than one egg per plant, I did find at least two eggs on some plants this year.
2nd & 3rd stage eggs
The photo above clearly (well not that clearly actually) shows two eggs on the same plant and at different stages of development and as I've read that females will deposit a pheromone to deter future females,wonder if these were actually laid by one individual on different days, or just developed at a different rate as larvae do.

The other thing about these eggs is that they were laid not on Cuckooflower but on Winter-cress (Barbarea vulgaris).

As I understand it, winter-cress is  biennial  and so it seems strange to me that the butterflies would choose it to lay eggs on, knowing that the larvae would feed on the plant after emergence and yet being biennial, would there be any plant to feed on?

Once the eggs become this brilliant orange colour the next thing that happens is the appearance of darker spots, as shown in the photo to the left. This particular shot was taken on the 18th April and shortly afterwards the egg changed again to a darker, mottled colour that was a sure sign that emergence of the larva was imminent. I'd been keeping an eye on these eggs for quite a while in the hope of being fortunate enough to catch a photograph or two of either the tiny larvae emerging, or perhaps the newly emerged, first instars (there are 4 moults in total), or even if I was really lucky, both. Providing of course that my skills with the camera would be consummate enough to capture anything this small worthy of sharing. 

Almost cooked

  Well I didn't have to wait too long, on April 19th when I did my early morning check on the eggs, some minute larvae had already emerged and were going about their business of finding food-something that would occupy them for the next 3 to 4 weeks.

A first instar larva
As you can probably tell from the photograph above, the thickness of the Cuckooflower stem the larva is on would be no more than a few millimetres wide and the caterpillar is only around one third of that and so obviously very small.
They are also on emergence this kind of translucent amber colour but will gradually change with each moult to the more recognisable green/grey of the adult larva. Once free of the egg, the young larvae will eat the eggshell and also in a cannibalistic manner, any other eggs in the vicinity. From observing them this year, I noticed for the first time that they will also eat the exuviae produced at the moult stage-this was particularly interesting to watch and record being a first for me.

A later stage caterpillar eating the moult

Notice how in this later stage caterpillar the colouring has already undergone a change towards green.
I continued to watch and record the caterpillars and noted that they seemed to feed mainly on the developing seed-pods as well as leaves and even the flowers.
With each new moult they seemed to be acquiring both the recognisable colour of the adults along with an increasingly good camouflage.
By April 14th I measured one at just a little over 25mm         


Once the larvae have reached maturity the feeding seems to increase until it seems to be just about all they do (well that and poo!) but eventually the frenzy abates and their metabolism seems to slow until they become less frenetic and begin to leave the food-plant in search of a pupation site.

The larvae are known to travel extensively in search of a good pupation site and that usually means a scrubby area with lots of low undergrowth where they can safely spend the winter.

The start of pupation showing the silk girdle

When the perfect spot has been located by the adult caterpillar it will climb a plant stem and begin the process of pupation by attaching itself to the plant with it's rear end by means of the cremaster, a cluster of minute hooks used to grip and then forming an arc, head-down.

Orange-tips belong to the family 'Pieridae' and all of this particular family use a silk girdle sewn by the caterpillar itself to hold the pupa steady.

Soon the caterpillar begins to undergo some amazing changes-this is a truly absorbing thing to watch as the head-end morphs into a completely different creature that on one hand somehow reminds me of those fabulous eastern jade figures, and yet on the other, even at this early stage, there are clear signs of the butterfly taking shape.

In the above close-up shot, the head,wings and what will be antennae are already clearly defined; just amazing to me, how can something change shape before your eyes? It's not even like the final process where the old body of the larva gets broken down into a kind of soup and then reforms within the chrysalis, I can understand that to some extent. If you stood and watched long enough, you could actually watch this take place.

Orange-tip pupa
Eventually the caterpillar is completely transformed into a pupa and it will now remain in this state through the rest of the season, right through winter and into next spring before a butterfly emerges to start the whole process over.

A mature Orange-tip pupa

Over time, as the pupa hardens it begins to change from green to cream/white, a colour much better suited to the winter surroundings and therefore increasing it's chances of survival.

And so that's where we must leave the story of the Orange-tips for this year. It was actually a good year for this species locally as it was for Ringlet but numbers of Common Blue and Comma were well down.
I would very much like to be able to photograph the emerging butterflies next spring to complete the whole process of metamorphosis but right now, that's over 3 months away, we have winter to contend with first.

Until the next time then...

Friday, December 23, 2011

The Beetles...

Every once in a while something unexpected turns up and makes my day.
Such was the case today when I discovered a small beetle that even though I have been photographing beetles since around 2008 I have never seen before.

Here's the information:

Scientific name: Cassida nobilis
              Order: Coleoptera
             Family: Chrysomelidae

Cassida nobilis is around 5mm long, it's body is broad, somewhat flattened and oval. It hides both it's head and legs, sitting close to the plant surface and the large, flat neck shield and elytra make the beetle difficult to detect when at rest.

Cassida nobilis (Gold-striped Tortoise Beetle)
I've been unable to establish exactly how many species of Tortoise Beetle are present in the U.K. but I'm sure it's at least six-possibly seven and could be more.

I have found a couple of others and look how different C.nobilis looks to C.viridis...

Cassida viridis (The Green Tortoise Beetle)
And then C.rubiginosa that appears similar to viridis at first glance...

Cassida rubiginosa (The Thistle Tortoise Beetle)
C.nobilis is listed as widespread but very local in England and seems to be more common at the coast.

The beetle is listed as a Notable B. species, meaning that it is a nationally scarce insect.


I was really pleased to find this one. Not only because it's another to add to my list of finds but more importantly, it means we have some scarce beetles living right on our doorstep.

I think it's a stunning little creature and probably the most impressive of the tortoise beetles that I've found to date; even though it's the smallest with the others being between 7-10mm.

Although this beetle also has the name of gold-striped tortoise beetle, in actual fact the stripes on this example appeared to me to be more mint-green, moving towards yellow in different lighting conditions. But then, I suppose 'gold' has oft been used with a little bit of artistic licence to represent yellow.

I would have loved the opportunity to take some natural light shots of this one but a dull and overcast late December day, with rain threatening isn't really conducive to macro photography; however, I did take just one, not fantastic because of the problems that I've referred to but here it is anyway...

Natural light shot of C. nobilis
All of these photographs were taken using a Canon 100mm macro lens with a Raynox M-250 attached.

Tortoise Beetle larvae in general are strange creatures that carry the excrement they produce on their backs.....

A tortoise beetle larva
That is Cassida nobilis-The Gold-striped Tortoise Beetle then. A fabulous find that I wanted to share.

Until the next time then...

Sunday, December 11, 2011

The most abundant microscopic animal in the world?

Orchesella villosa

Collembola season is here again with the onset of winter. By that I mean that those of us who chose to spend time hunting down these little creatures, when really we should be tucked-up safe inside our warm houses like any other sane person are once again finding that there isn't much else about to interest the macro photographer at this time of year.

These shy but often charming little creatures will be beyond the knowledge of most folks I guess, not because they are unworthy of a place in the world we all share but by virtue of their size (between 1-7mm) meaning that for the most part they are overlooked.

I don't want to get into a fact-file here of scientific detail, there are numerous sources available for that but here's a general outline of just what Collembola or Springtails as they are sometimes more commonly called are.

They are in fact not insects but wingless hexapods. There are currently around 8000 species that we know of worldwide.
They are soil and litter dwelling creatures, preferring damp conditions but can be seen on flowers in daylight.

I don't normally like quoting from Wikipedia but that's where this comes from:
Most species have an abdominal, tail-like appendage, the furcula, that is folded beneath the body to be used for jumping when the animal is threatened. It is held under tension by a small structure called the retinaculum and when released, snaps against the substrate, flinging the springtail into the air. All of this takes place in as little as 18 milliseconds.

Pogonognathellus longicornis

The springtail pictured above is probably our largest in the U.K. and also seems to have the longest name? I wonder if springtails play scrabble!

A few more of my recent Collembola finds...

As you can see from the pictures above, there are a huge variety of these beasties to be found. They do seem to come in a tremendous selection of colours and markings. It's very easy to become hooked on finding a fresh species, that is new to me, although it is quite possible that there are still new to science species to be discovered right here in the U.K. and in fact I do know of somebody that's done just that.
There's a really interesting video of springtails taken from the BBCs Life In The Undergrowth series and you can access it

Sminthurus viridis
Sminthurus viridis is one of the globular springtails and is also known as the clover springtail for obvious reasons.
This particular species was accidentally introduced into Australia where it is now considered a pest.

Symphpleona species

The colourful collembola above represents some of the problems I have trying to capture images of these tiny things. When I saw this one I knew I had to get a photo but didn't have the macro kit with me and so struggled to get any kind of picture and even then, had to resort to a large crop.

I normally would use a mixture of reverse lens techniques, along with the use of extension tubes and microscope lenses, all of which have their own problems-depth of field-lighting and focusing being the main ones.
This springtail is one of my latest finds and an exact identity has yet to be confirmed.

This ultra macro of a Dicyrtomina saundersi shot from above shows the articulated neck.

Sminthurinus igniceps
This one in the photo above measures less than 1mm and provided, well let's say something of a challenge to photograph.

Heteromurus nitidus
Heteromurus nitidus is a widespread species found in a variety of habitats including caves. 

I think my finds of these interesting creatures by way of different species totals around 35 or so at present but no doubt I shall be adding to the tally any day now.Of course 35 only represents about one tenth of the known U.K. species and if I am to get anywhere near that (little chance) then I have a good number of stones to turn and logs to look under yet.

Bourletiella arvalis
Bourletiella arvalis is yet another of the tiny springtails that although common is rarely recorded. This one is also under 1mm and looks a little like a miniature lemon on legs! I've only ever found one example and that was scurrying around the garden amongst the plants.

That's springtails then-the most abundant microscopic animal in the world, found in nearly every habitat and yet most people have and probably never will come across them.

Until the next time...