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Sunday, April 25, 2010

Multipedal Creatures cannot count

The other day I was cleaning out some timber which was left over form my house building project (the original project was to re-build the house after it was moved in to Robertson from Sydney).

Anyway, I foolishly just threw some bits of good "3x2" hardwood (which had been used to reinforce the house during the original move) under the house. I figured that as they would be dry under the house, everything would be OK. Of course, "dry" is a relative term in Robertson, and anything in contact with the soil here will not be completely dry, ever. That means potential mould, potential insect attack, potential disaster.

Local wisdom has it that termites do not like Robertson's rich red basalt, so they are not a threat (supposedly). But why take the risk? Plus, in the Post- Marysville-Kinglake Fires era, it is obvious that an open-sided, under-house area (the house is built up at the deep end on brick piers) is a potential fire hazard. One should not discount the fact that I have local rainforest on the south-west of the house. It is not Eucalypt Forest. Local rainforest is established, historically, to be far less likely to burn (than Eucalypt forest), and if it does burn, it tends to burn slowly, not "explode".

All that aside, I have decided to clear out the under-floor area completely.

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I made a start by pulling out the rubbishy bits of timber and spare "weatherboards" which I no longer need as spares, in view of the fact that I am replacing the timber boards with Hardiplank (in a profile matching the original Weatherboards, to suit the styling of the era of the original house).

Then it came to pulling out some really long boards of hardwood (those 3x2s I mentioned). I had used these long boards to strap down the tarpaulin which the removalist had supplied. He had made a supposed attempt to weather-proof the house after he had moved it here. His tarpaulins were really cheap and nasty and could not withstand the wind (firstly) and then the rain of that season. We had 12 inches of rain in February and 15 inches in May, that year. It nearly destroyed my little house before I could get the roof rebuilt. Fortunately, I got the roof re-built - properly, eventually, and then replaced much of the damaged interior plaster. Not a drop of moisture has entered the house since the newly rebuilt roof was completed.

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What has all this got to do with nearly microscopic creatures?

Well, while I was under the house, pulling out the timber I noticed some signs of insect damage to the timber. Alarm bells rang in my mind. Were these Termites?

I quickly called my brother Brendan, (who is the builder doing most of the reconstruction work on the re-cladding project) and we examined these insects microscopically (courtesy of the camera's excellent new 105mm "Micro" lens). I could see immediately that they (whatever they were) had lots of legs. Termites have 6 legs (only), as they are classic "insects". So that was ruled out. But what were these little white creatures?

A "gorgeous Symphyla" according to Bob Mesibov.
I agree, now that I know it and its friends are not going to eat my house.
Click to see the full details of this tiny creature, and its very fine antennae.
Fortunately, last year I had met Australia's leading Millipede expert (or should that be Australia's "sole" Millipede expert?) - Bob Mesibov of Tasmania.

I sent Bob a message yesterday, with a photo and a query.

From several websites he runs, on behalf of the Tasmanian University, I had already worked out that my little creatures were likely to be a class of tiny "multipedes" known as Symphyla.

I knew it wasn't a Millipede (single legs, not paired) but when I went searching for Centipedes I found Bob's page on Tasmanian Multipedes, http://www.qvmag.tas.gov.au/zoology/multipedes/mulid.html
which led me to this statement:
  • Symphyla have unbranched antennae, 12 pairs of legs and 2 tail-like appendages (cerci) at the rear end (below centre). Centipedes have at least 15 pairs of legs as adults. Some juvenile centipedes have fewer than 15 pairs of legs, but these juveniles can be distinguished from Pauropoda because the antennae are unbranched, and from Symphyla because the rear end lacks cerci.
I then found his page on Tasmanian Symphyla, which tells me:
  • "Symphyla are small, blind, fast-running multipedes which can be very abundant in soil and forest litter. They are generally white, but dark-coloured gut contents can often be seen through the body wall. Not much is known about the biology of Australian native Symphyla. They occur in a wide range of macrohabitats and are believed to feed on soil microbes, both 'free' and attached to decaying wood and vegetation."
  • http://www.qvmag.tas.gov.au/zoology/multipedes/tassymph/symintro.html
Bob kindly sent me the following reply, late last night.
    Hi, Denis.

    Gorgeous Symphyla, great picture, not a threat to anyone's house!

    Cheers,
    Bob
    --
    Dr Robert Mesibov
    Honorary Research Associate
    Queen Victoria Museum and Art Gallery, and
    School of Zoology, University of Tasmania
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According to the texts, Symphyla generally have 12 pairs of legs, and unlike millipedes, they have a single pair of legs per body segment (Millipedes have legs in double pairs). That makes these creatures closer to tiny Centipedes, but Centipedes tend to have more legs (except in their immature stages).

And what is my point?

Well, several days ago my Blogging colleague, Martin, objected to the idea of re-classifying Fungi as their own separate Kingdom of creatures (separate from Plants). Fair enough, I grew up with the notion of certainty involved in the classic 3 classifications of Nature: Animal, Vegetable and Mineral. So I can sympathise with Martin in his loss of certainty.

I feel similarly disturbed by the idea that there are creatures out there - tiny creatures which we hardly even notice - which might have 11 or 12 pairs of legs, or that their larval stages might have fewer than the standard number.

What's wrong with these creatures? Haven't they read their own "Manual", which would tell them the proper number of legs for them to have?

We all know that "animals" (quadrupeds) have 4 legs (except in Humans, our "front legs" have become known as "arms", but we do have 4 limbs). Insects have 6 legs, Spiders have 8 (as do Octopuses), and Squid have 10 legs). These creatures known as Symphyla, supposedly have 12 pairs of legs, Centipedes might have up to 15 pairs (not 50 pairs despite their name) and Millipedes.... well, who knows? They do have "two pairs of legs on most posterior body segments". It seems the number of "body segments" might vary, depending upon their level of maturity.

Anyway, I find the casual attitude of many creatures to the number of legs they have quite disturbing. I just learnt that Mites have 8 legs, and so earn a place in the order Arachnida (Spiders and their allies). That's fine, but in their nymph stages of some species may have 6 legs, not 8. There's that casual attitude to Natural Design again. Can't these creatures count?

So, my little Symphyla appears to have 11 pairs of legs (not 12 that I can see). But I would have to say that it has a very handsome set of antennae, which were being waved around very actively.

The fact that this little creature was so active, and so small (I estimated it to be 3mm body and 2mm antennae) meant that it was a challenge to get a decent photograph. I was operating on the maximum close-up range of my "Macro Lens", and as I have to use the optical view finder, (not a digital preview screen), that means I have to get my head in there, and hold both my head and the camera steady (to within a few millimetres) or else the tiny creature goes out of focus. And while I am struggling to get it in focus, it runs under a piece of dirt - and I start all over again.

Its hard work taking clear photos of such tiny creatures. And it does not help the amateur naturalist, when he gets a clear photo (eventually) and looks up the appropriate references, to discover that the creatures themselves cannot count the correct number of legs on which to walk about - in the dirt and detritus which they so love.

But it is a cute Symphyla, as multipedes go!
I hope you agree with me.

7 comments:

mick said...

I am intrigued with the breadth of your knowledge! - Plus I always find your posts interesting! However, I must admit that the most 'intriguing' part was imagining you down under the house, in the dirt, with your face a few cms from these little white wriggling creatures!!

Flabmeister said...

Denis

Zooming in to the image shows an astonishing level of complexity in the antenna. Very we;; [peresevered to get it.

While super-sized I also looked closely at the leg arrangement and it seemed to me that the left leg was missing from the 7th segment and the right leg from the 8th. This reminded me very much of the occasional unipedal gull and makes me wonder whether your animalicule had received external assitance in failing to have the correct arrangment of legs?

Denis Wilson said...

Bob Mesibov has sprung to the defence of the Multipedes, following my attack on their apparent inability to count.
He has sent me the following message:

Hi, Denis.

They can too count!
It's just that your pictured animal is a juvenile. Symphyla start off with 6 pairs of legs and add more pairs as they moult, the last juvenile stage having 11 pairs.

The technical name for sequentially adding legs in this way is anamorphosis The opposite is epimorphosis, in which juveniles are born with the full adult number of legs.
.
All millipedes, all Pauropoda, all Symphyla and some centipedes (the ones with 15 pairs of legs as adults) develop by anamorphosis. Epimorphic centipedes have *more* legs than anamorphic centipedes: 21-23 pairs in one group, and more than 27 in the other.
I realise this is counter-intuitive, but such is life.

Interestingly. the man who first clearly explained how Symphyla grow was the Australian O.W. Tiegs:

See this Wikipedia link

Best wishes,
Bob

So, there we are.
My tongue in cheek comment (title of the Post) has both been verified and discredited in the one comment.

My observation was correct (11 legs), but the reason has now been explained!
.
How many new words did you add to your Lexicon today?
I got at least 8.
A good days, work I reckon!

Many thanks to Bob Mesibov, a scientist with a sense of humour. And above all a man who loves his tiny multi-legged creatures.

Cheers
Denis

Denis Wilson said...

Hi Martin
I pondered, and counted and recounted the legs many times.
.
I suspect that the middle segments (3,4,5,6, & 7) actually have a double shell, and so it appears that there ought be a leg (or two) more than there are.
.
Bob's explanation is simpler.
.
Re what is happening on the far side, it is hard enough to tell what's going on on the near side.
I cannot get an X-Ray machine that small.
Electron Microscopes come into their own for anything smaller. But of course, there is a "cost" (for the specimens) in lining them up to sit still for the EM machine.
.
My little guy escaped with his life. The ones Scientists "collect" do not.
.
But my brother has pointed out privately that, just to be on the safe side, I did waste half a bottle of Turps in the nest under the house.
.
But I am sure there are hundreds, if not millions of these little guys in the rainforest next door.
.
Next time I encounter them, I will be more respectful.
.
It is just that I was in a seriously "negative" frame of mind with regard to little white creatures which eat timber, having just rebuilt a corner of my house in order to repair pre-existing Termite damage.
.
That is not funny! Hence what turns out to have been an over-reaction. It seemed reasonable at the time, because having moved the timber away, I assumed they would relocate their nest. And if they were at all dangerous (to the house) I did not want them doing that.
.
Perhaps I shall light 11 candles (or 12) in their honour!
.
Cheers
Denis

Denis Wilson said...

Hi Mick
Well I cannot claim any great knowledge on this subject, but my friendly contacts have helped me greatly.
I did not reveal that the Symphyla was on the back of a piece of wood which I dragged out from under the house, as I could see it had been chewed into to a small extent.
As it turned out, it was minor external damage, probably mostly fungal activity, if the truth be known.
But at that stage I was taking no chances.
That's why I dragged the wood out, and studied it in good light. Photo was flash assisted, even in daylight. It helps with Macro images. That's how the details of the nodes on the antennae etc, come up so clearly.
As for "knowledge", don't underestimate your knowledge of tides and waders and Terns, and all sorts of coastal stuff either.
Cheers
Denis

Mosura said...

An interesting post. I don't think I've actually seen a Symphylan.

Denis Wilson said...

Hi Mosura
Glad you found it interesting.
Look for tiny little white wiggly things in dirt and plant humus.
Quite active.
Cheers
Denis