Sunday, September 30, 2012

Caterpillars preparing for winter...

As things start to wind down for winter, any of the species that hope to survive the season are now making final preparations. I have been watching a reasonably large collection of Buff-Tip Moth caterpillars over the past few weeks as they furiously feed up before pupating...

They live gregariously until the final instar and will often twist around each other on a single twig, as in the photo above. Fully grown they can reach 60mm in length and look very impressive, as does the damage they can inflict on the host plant-in this case oak.

When they undergo a moult, they seem to be able to do so in the same position and more-or-less at the same time...

The remains of a mass-moult
The black spots on a bright yellow or orange background make this caterpillar very conspicuous and also of course, warn of its poisonous nature.

If that wasn't enough to deter any unsuspecting predator, it also has an unpleasant smell. The mature caterpillar has this striking yellow inverted 'Y' on its head.

Through last week the feeding became a lot more frenetic as the time neared for pupation. I've noticed when observing other species that just before pupation takes place, the feeding will become very intense. I also witnessed  how the group was dispersing, and saw several individuals strip an oak branch of its leaves in no time and would then be left dangling from what remains...

Although these caterpillars can be around until into October  this particular bunch have in fact now all pupated. This involved leaving the host plant/tree and once they reached the ground, bury themselves in the earth, just below the surface where they will spend the winter before emerging as the adult moths next springtime.

This is one of the last photographs I took before they all disappeared below ground...

This photo below demonstrates how the process begins, it was taken a few days after the caterpillars left the tree...

The whole transformation into a pupa seems to take quite a while in this species, especially compared to butterflies, which I've watched pupate in less than half an hour.

From looking as though they have died in the early stages, the next photograph shows how fantastic they look at the second stage...

Then finally, as the whole process is completed, they attain the darker colours that will help to camouflage them throughout the winter months should they be unearthed, or come to the surface for any reason...

I look forward to being able to bring you shots of the adult moths next year.

Until the next time...

Sunday, September 23, 2012

I reveal just how hoverflies keep fit...

I recently had to search through some older images that I have stored on the P.C. for a particular few shots and happened upon a couple of unused photos from earlier in the year.

And so now, they are at last seeing the light of day, as I'll start this update by adding them here...

A Weevil (possibly Stophosoma?)

This large weevil was one that I remember finding in mixed woodland on one of my many walks.

The varied carpet beetle (Anthrenus verbasci)
The little beetle pictured above was one that I found in the garden on a white daisy and photographed using a broken lens that had no front glass!

A couple of days ago, my other half said that she'd saved a large beetle that had somehow got itself in an argument with the hoover and lost. Rather than bin it, she had thoughtfully wrapped it in a sheet of kitchen towel, in case I might like to photograph it first?

On unwrapping the towel, I found the beetle you see pictured below-as you can see, it sustained several injuries but I decided it would make an ideal subject for focus stacking....

Lesser Stag Beetle (Dorcus parallelopipedus)
After much consideration, I went for the lesser stag beetle as an identity. Based on the shape of the pronotum and the spine on the tibiae. The other choice would have been a female stag beetle.

I recently posted a photo on flickr of some Sawfly Larvae that were still inside the eggs. It was a shot taken using flash to get as much detail as possible- but I also took a few more natural light photos that give a better overall impression of how they looked in relation to the leaf I found them on...

 Click on photos for a larger view

You can see just how destructive these can be to the host plant, in this case willow. They have only just emerged and yet are demolishing the leaf already.

On the same day I discovered these little things, I also came across some more eggs. This time bug eggs:or at least, bug eggshells, as I think the occupants of these had long gone..

I love those little hinges (or are they catches?) on the eggs. Whichever they are, I am sure they're purpose is to allow an easy exit when the time comes.

I had a second chance to create a focus stack of an insect when I happened upon a lacewing that had somehow managed to fall into a cattle-water trough. At least, I assume it fell in? I certainly didn't push it! In fact, I scooped out several deceased bugs and insects that I may also use for the same purpose.

I photographed these two at x10 mag.

I really will have to try and update the microscope objective from my £1 edition at some stage-it really doesn't have much going for it apart from it is useful to practice with and I suppose, to even get these results is O.K.

Now that most of the summer wild-flowers have finished for this year, it's left to the flea-bane to attract the insects and it does seem to be doing just that. I found a good number of hoverflies on flea-bane in local woodland and even managed to photograph one doing press-ups...

I have included a couple of focus stacked images in this blog entry and this next photo is a good example of how things can go wrong when attempting a hand-held stack in the field.

There's not doubt in my mind that this photo is sharper than a single image would have been, without using a tripod- but there are only two shots that comprise this stack:the third that would have completed it as intended and would have resulted in both wings being in focus, unfortunately was just a little too far out of line to use.

The only other thing to report in this entry is the return of the harvestmen. As you would expect at this time of year, they are emerging in numbers and a variety of shapes, sizes and colours right now...

Dicranopalus ramosus
Until the next time then...

Tuesday, September 11, 2012

Don't ask stupid questions, unless you want a stupid answer...

`It seems hard to believe but my stats tell me that I've had this blog since November 2010 and in that time I've had close to 10,000 views.

The map below also shows how it now gets read in an ever growing number of countries too, with the green shaded ones being where folks are kind enough to read these missives.

Time then to thank everyone that's either been here from the start or has joined along the way. I'm very grateful that you're there for me, it would all seem a little pointless without you.

Let's crack on with the latest update then...

A couple of things to tie-up from the last entry:in fact, this relates to the previous one as well-the shieldbug nymphs that I've been finding on alder recently.
I've been observing how the nymphs are progressing and today found something rather special.

This was one of those 'Wow' moments that leave you feeling that you have been privileged to be an observer of nature at its most remarkable...

These tiny nymphs were mid-moult when I found them and were struggling to free themselves from their old skins. I was transfixed by this and somehow felt sorry for them, unable to help. It seems such a hazardous thing to have to undergo and to think they have to do it several times before becoming an adult.

I've only been lucky enough to photograph this behaviour once before,and never with this species. It really made my day.

Once the nymphs had fully emerged I could see that underneath there was an adult parent bug. There also seems to be a hawthorn shieldbug nymph looking on.

Hawthorn Shieldbug nymph
Whilst I seem to be compiling quite a nice little set of shieldbugs and their nymphs, here's another to add to the count...

Final instar Woundwort Shieldbug nymph

I hinted in my last update that the rare sawfly larva I'd found wasn't the only uncommon find and I can reveal that my other rarity was...well, have a look at the following photo...

By the way, before I tell the identity of this beetle (if you haven't already guessed that is) why does it always seem to be that when something of real interest like this turns up, you can bet there will only be just one chance of getting a photo and then you'll probably mess-up?

This is not the best shot you'll ever see of this small beetle, but it is the only shot I managed!

Platycis minutus is an 8mm beetle that has a Notable B. status in the U.K.
Looking for all the world like a miniature cardinal beetle but identifiable by amongst other things, the buff antennae ends.

Angle Shades Moth
A couple of moths now:always a pleasure to see these beautifully marked moths. This one was resting on teasel as you can probably tell.

 It has also reminded me of something else that could be considered another unwritten law of macro photography-why is it that just as you settle down to take a photo, in what appears to be total solitude, as soon as your finger hovers over the shutter button, somebody materialises out of the ether and insists on either telling you their live history, or asks the immortal and familiar question..."What are you doing?"- "I'm fishing! What does it look like I'm doing pointing a camera at a moth?" Well that's how the reply goes in my head sometimes, I've not been brave enough to voice it......yet!

The Herald
Clock this one! Scoliopteryx libatrix or The Herald to you and me. This is possibly where I should add the usual bit about clicking on any photo for a larger view, you won't regret it with this stunning insect. If there's a more beautifully marked moth then...well O.K.There are so many moths that chances are there will be, but still, what a beauty and fresh as a daisy.

I seem to be skipping from one species to another here- It's just not cricket is it? But next up is member of the Tettigoniidae family. 

Oh! It is cricket after all! To be precise, a female oak bush-cricket. (I'm never quite sure as to whether I should use caps for species names?) Nothing too remarkable about finding an oak bush cricket on oak of course, a couple of things struck me about this individual though.

The first obvious one was the wing position. I've not seen them being held in this way before. and what about that dodgy antennae too? Then (and now might be an opportune moment to do that 'view larger' thingy again) I noticed something strange about the 'knees'.

I think this may be in the early stages of succumbing to the fungus that takes over its host and encourages it to climb to a high point, in order to spread the wind blown spores over as wide an area as possible?

Enough of the grizzly side of nature-time for an arty spider shot. Taken from quite a distance this one, I liked the way the seeds from the nearby willow herb had settled in the web.

I'm thinking that one more species might well be enough for this update and so I'll leave you with a mollusc...

I was really pleased that this shot turned out as well as it has because the little snail here is only around 5-6mm and I didn't use flash. I haven't been able to put an i.d. to it but I really like it-it reminds me of the coloured glass marbles we used to have as kids.

Until the next time...

Finally,finally! No news to impart regarding the African snail eggs I'm afraid-have given up hope now.

All photos taken with Canon 40d Canon 100mm macro lens and natural light.

Thursday, September 06, 2012

Possibly a first for Kent...

Having allowed a few days to pass since my last update, I re-visited the spot where I located the shieldbug nymphs. I was hoping to perhaps find some parent bug instars this time.
These little nymphs are quite impressive in their stripped waistcoats and having found adults, I was optimistic...

Elasmucha grisea
My enthusiasm may have been a little misplaced, as I only found one individual today, but I was pleased with one and surprised at how much detail I managed in a natural light shot of it. 

Here's where the story got interesting for me, and why I wanted to link this blog update with the last.

What did I originally find here? Well, a Birch Shieldbug and a Parent Bug. Both of these species are associated with the birch tree. I have to admit to not examining the bark of the tree but did look at the leaves, and yes, they looked like birch.
A reasonable assumption would be that it was a birch tree then?

Well yes, but then when I returned a few days later I found a cracking little sawfly larva on the same tree...

Cimbex connatus
And what's so special about this particular sawfly larva? Actually quite a lot!
It seems that it's something of a rarity:at least, until recently anyhow.

The U.K. status is listed as follows: Once thought to be extinct in Britain, it was re-discovered in Wiltshire in the 1990's and has since spread through southern England.

Here's an NBN Gateway map for the species...

As you can see, there only a couple of records .Probably under-recorded to some extent, but still a nice find with no records in my area at all.

A Large Alder Sawfly larva
I've given this dorsal view its common name to illustrate how all this fits together.

And so this is an Alder Sawfly-not associated with birch then? So now we have on the same tree, two species correctly associated, and one not. O.K. no problem, it's quite common for a species to be found on a plant or tree other than the preferred choice. 

If the discovery of this sawfly larva was noteworthy for its rarity value, then my next find must be considered equally of merit for different reasons and top of the list would probably be something along the lines of 'what the heck...'

Eriocampa ovata

These larvae can grow up to 2cm long and are covered in this white powdery substance. This is supposed to protect them from predators who mistake them for bird-droppings. The white camouflage is easily rubbed off and in the final instar, when feeding is complete, the white powder is lost and the larvae adopts a pale green colour...

This sawfly larva is less rare than the previous, with at least a few records for Kent but most of the sighting do seem to have come from the south of the country.

And what's the common name for this species? The Alder Sawfly or sometimes The Woolly Alder Sawfly. we have two species assoc. with birch and two alder, all of which were found on the same tree.

Time to check this out then! Back for another, better look at the tree and the surrounding habitat.

Result: There are other alder trees close-by, alder are often found beside water (as this was) and on closer inspection the leaves have hairs on the underside. 

Conclusion: this was indeed an alder tree and not birch after all. Why then are two species of shieldbug closely associated with birch feeding on alder? I've not heard of, or indeed found this before but a safe guess would be that alder and birch actually belong in the same family of 'Betulacae'

I have to admit to finding this fascinating and really enjoyed the research into finding identities etc. I have yet another uncommon insect that I found this week, but I'll use this one as a little teaser to my next blog entry, which should be along any day.

Until the next time then...

Monday, September 03, 2012

How many shieldbugs make an autumn?

September means that even if we don't want to admit that autumn is here, it's certainly on its way. Autumn can be a good time to spot some of our native invertebrates though-dragonfly numbers are peaking and adult shieldbugs can be quite numerous, including Sloe Bugs, Forest Bugs, the tree dwelling 'Troilus luridus' and the ever present Green Shieldbug.

One of the smaller shieldbugs that seem to be quite numerous around early autumn time, is the Birch Shieldbug (Elasmostethus interstinctus) and both the nymphs and adults are quite striking...

Click on any photo for a larger view

I think these two pictures above show what are probably 3rd instar nymphs of the Birch Shieldbug. They were quite small and reasonably fast moving.

A slightly larger nymph

A final instar nymph
All of the nymphs featured here were found in the same spot, a birch tree beside a local pond. Some were underneath the leaves and others quite easy to spot against the darker upper-side of a leaf.

There were also a number of the adult insects on the same tree...

The adult

As you can see, they are very colourful little bugs. These shots have not been enhanced in any way either; it was a dull day and had been raining before I took these photos, hence the sheen some of them have but other than reducing the size to upload to the blog, this is exactly how they looked.

The birch tree in question seemed to have a thriving little shieldbug community as I also found a couple of parent bugs as well...

A Parent Bug

I shouldn't have been surprised I suppose at finding this bug-after all, it is associated with birch as well. Once again these are beautifully coloured bugs and like the green shieldbugs, hibernate through the winter months.

This one may be lucky to make it to winter, as those white spots on it's back are parasites. I've seen this species with the same parasite before and I think they are Tachinid fly parasites:they are laid in this position where it is almost impossible for the bug to remove them.

The parent bug gets its name from the females habit of sitting on her eggs and nymphs to protect them from parasites and I've often wondered if she has become the target rather than her offspring?

Troilus luridus
Troilus luridus is another tree dwelling shieldbug and is quite a bit larger than both the birch and parent bugs. It is also a predatory bug, rather than feeding on plants.

This photo shows a final instar Troilus luridus nymph feeding on a large caterpillar. I watched this take place and the caterpillar had no chance of escape-it was busy feeding when the nymph sidled up to it and inserted its proboscis before the larva could do anything at all;although, even given time, I'm not sure what it could have done?

Those then are some of the recent shieldbugs that I've found whilst out walking locally-in case you are thinking of trying to locate some for yourself, here's a snap of the tree and habitat where I found most of mine...

Until the next time then...

All photos in this blog entry taken with the 100mm macro leans and natural light only-I used my Canon 40d camera.