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Monday, 30 April 2012

Some thoughts about insects

Well, the new book is out tomorrow, and today I tramp the media trail, yacking about it on radio.

As a goodly part of Australian Backyard Naturalist is about insects, here are some odd thoughts on insects from my quotes file. It will be two or three days until I have time free to do regular posts here.
I believe that our very concept of beauty, necessarily relative and cultural, has over the centuries patterned itself on them, as on the stars, the mountains, and the sea.  We have proof of this if we consider what happens when we examine the head of a butterfly under the microscope; for the greater part of observers, admiration is replaced by horror or revulsion.
— Primo Levi, 'Butterflies' in Other People's Trades, p. 7

Happiness is like a butterfly which appears and delights us for one brief moment, but soon flits away.
— Anna Pavlova (1881-1931), Russian ballerina.

 It is said that the famous British biologist, J. B. S. Haldane ... asked by a churchman what his concept of God was, answered: 'He is inordinately fond of beetles'.
 — Primo Levi, 'Beetles' in Other People's Trades, page 14

It appears, by the dung that they drop on the turf, that beetles are no inconsiderable part of their food.
— Gilbert White (1720 - 1793), The Natural History of Selborne, (1789), Letter XXVII, about hedgehogs.

March 28.  A neighbour complained to me that her house was over-run with a kind of black-beetle, or as she expressed herself, with a kind of black-bob, which swarmed in her kitchen when they get up in a morning before daybreak.  Soon after this account, I observed an unusual insect in one of my dark chimney-closets; & find since that in the night they swarm also in my kitchen.  On examination I soon ascertained the Species to be the Blatta orientalis of Linnaeus, & the Blatta molendinaria of Mouffet.  The male is winged, the female is not; but shows somewhat like the rudiments of wings, as if in the pupa state.  These insects belonged originally in the warmer parts of America, & were conveyed from thence by shipping to the East Indies; & by means of commerce begin to prevail in the more N. parts of Europe, as Russia, Sweden &c.  How long they have abounded in England I cannot say; but have never observed them in my house 'till lately. [They had probably been there since late in the 17th century]
— Gilbert White (1720 - 1793), Journal, (1790), MIT Press, 1970.

 When the servants are gone to bed, the kitchen-hearth swarms with minute crickets not so big as fleas.  The Blattae are almost subdued by the persevering assiduity of Mrs. J. W. who waged war with them for many months, & destroyed thousands: at first she killed some hundreds every night.
— Gilbert White (1720 - 1793), Journal, (1792), MIT Press, 1970.

And you should never own to a mosquito.  I once unfortunately stated to a Queensland gentleman that my coat had been bitten by cockroaches at his brother's house, which I had just left.  'You must have brought them with you then,' was the fraternal defence immediately set up.  I was compelled at once to antedate the cockroaches to my previous resting-place, owned by a friend, not by a brother.  'It is possible,' said the squatter, 'but I think you must have had them with you longer than that.'  I acquiesced in silence, and said no more about my coat till I could get it mended elsewhere.
— Trollope, Anthony, Australia and New Zealand, London: 1873 and Brisbane: University of Queensland Press, 1967 (edited by Edwards and Joyce), page 67.
  And some taxonomy thoughts:
 Taxonomy, the most underappreciated of all sciences, is the keystone of historical disciplines.

— Stephen Jay Gould, The Flamingo's Smile, Penguin 1991, 19.

All flying insects that walk on all fours are to be detestable to you.  There are, however, some winged creatures that walk on all fours that you may eat: those that have jointed legs for hopping on the ground.  Of these you may eat any kind of locust, katydid, cricket or grasshopper.  But all other winged creatures that have four legs you are to detest.
Holy Bible, Leviticus, 11:20-23, New International Version.

The fact that we are able to classify organisms at all in accordance with the structural characteristics which they present, is due to the fact of their being related by descent.
— Ray Lankester (1847 - 1929)

There are really only individuals in nature, and genera, orders and classes exist only in our imagination.
 — Georges Buffon (1707 - 1788).

I suspect much there may be two species of water-rats.  Ray says, and Linnaeus after him, that the water-rat is web-footed behind.  Now I have discovered a rat on the banks of our little stream that is not web-footed, and yet is an excellent swimmer and diver. . .
— Gilbert White (1720 - 1793), The Natural History of Selborne, (1789), Letter X.

Modern biologists sometimes do less than justice to the genius of the men who, behind the bewildering variety of morphologies and modes of life of living beings, succeeded in identifying, if not a unique 'form', at least a finite number of anatomical archetypes, each of them invariant within the group characterized.  It was of course not difficult to see that seals are mammals closely related to carnivores living on land.  It was much harder to discern the same fundamental scheme in the tunicates and the vertebrates, so as to group them together in the phylum Chordata; and it was still more a feat to perceive the affinities between chordates and echinoderms; yet it is certain, and biochemistry confirms it, that sea urchins are more closely related to us than the members of certain much more evolved groups of invertebrates such as the cephalopods, for example.
 — Jacques Monod (trans. Austryn Wainhouse), Chance and Necessity, Fontana 1974, p. 100.

A plant should be mutually known from its specific name, and the name from the plant, and both from their proper character, written in the former and delineated in the latter.
 — Carl von Linné (Linnaeus) (1707 - 1778), The Elements of Botany (1775), quoted by Francois Jacob, The Logic of Life (1973).

It is a folly to use a great many where few words are sufficient.
— Carl von Linné (Linnaeus) (1707 - 1778), The Elements of Botany (1775), quoted by Francois Jacob, The Logic of Life (1973).

Life has come to be regarded by the majority of biologists as forming one vast genealogical tree, the roots of which are buried deep down in the lowest fossiliferous strata, and the tops of whose branches, constituting the life that now exists on the globe, are alone seen above the surface.
— John Gibson, 'Fossil fishes of Scotland' in Science Gleanings in Many Fields (1884).

... each pollen was very beautiful and specific: one could distinguish its separate granules, delicate and elegant architectures, small spheres, ovoids, polyhedrons, some smooth and shiny, others bristling with ridges or thorns, white, brown, or golden.
— Primo Levi, 'The Invisible World' in Other People's Trades, page 50.

Sunday, 29 April 2012

Plague germs in Melbourne

This is out of the normal run of things, but this is too good a yarn not to share.

For reasons that I won't elaborate on here, I have been looking at the bubonic plague outbreak that happened in Sydney at the start of the 20th century, when fast steamers were able to carry plague rats to a number of Pacific and Asian ports.

To get some good background, I started wading through reports from the start of 1897. I read of tick plagues, rabbit plagues, rinderpest, grasshoppers and more, because I had chosen the blunderbuss approach of searching just on plague. Using this method slows things down a bit, but ensures that I don't miss any gems.

I was working in my favourite resource, the Trove digitised newspapers collection at the National Library of Australia, and the 133rd article that I looked at was the one in the clipping on the right (or possibly above, depending on your browser and its settings).  If you want to read on (and I hope you will), here is a link to the whole article.

The skinny: Dr. Haydon had indeed brought back plague bacilli (interestingly, the story uses all three common terms: microbe, bacillus and germ).  He refused to hand them over, as he wanted to carry out experiments.

The authorities found they had no power to seize the bacteria, but then came a twist that W. S. Gilbert would have loved:
Microbes are not dutiable, and there is no law to prevent their importation, but the Secretary of Trade and Customs states that everyone coming to the colony is technically bound to report everything in his possession. Mr. Williams, at the interview with Dr. Wollaston, suggested that an officer of the Customs Department should be sent to seize the germs, and that Dr. Haydon, instead of being compensated; should be prosecuted for secretly importing the germs of a horribly dangerous disease.
Mr. Williams favored desperate measures, but as soon as Dr. Wollaston heard that the microbes had been imported in gelatine, he saw his opportunity to proceed in a legal manner, for gelatine is subject to a duty of 3d per lb, and, as Dr. Haydon had not paid the duty, the department was entitled to seize the gelatine; Mr. Williams gleamed with satisfaction, and Dr. Wollaston hastened to give effect to his intention.
And so it came to pass, in due course, that Detective-Inspector Christie, expert seizer and destroyer of illicit whisky stills, contraband cigars and the like, hastened off with Dr. Gray, seized the vile bugs and promptly consigned them to the fire.

Naturally, I suspected a leg-pull, but there was wide coverage over many years. Dr. Haydon was apparently Dr. Leonard G. Haydon.  Moreover, he had discussed his actions with officers of the Public Health Department, and they had seen the cultures.

Haydon offered a spirited defence of his actions in The Argus on November 14, and by his explanation and after tracing has later career (my search in Trove was on Haydon AND plague), I conclude that Haydon was in the right and the authorities were in full knee-jerk panic mode.

In fairness, there had been an outbreak in Vienna in the previous month, when several staff at a medical institute died of bubonic plague, and the method of transmission was yet to be worked out, so the fear was understandable.

But nothing can take away from the ploy about unpaid gelatine duties. What a pity only three other reports mention that aspect of the yarn.

Oh dear!  I think I may have been taken in by a bit of journalistic embellishment, corroborative detail, intended to give artistic verisimilitude to an otherwise bald and unconvincing narrative.

Remind me again: who was it that said that?

Addendum: after many years in South Africa, Leonard Guscote Haydon retired to Australia and died in 1941. Here is a link to an obituary.

Saturday, 28 April 2012

The mysterious cloven-hoofed animals of Australia

No hoof here: this is a 2-metre
portion of a snake's track, left
on a fire trail near Sydney.
I was going to write about tracks in the next few entries, and indeed I will, but first, a bit of history that stems from a current early-stages writing project which has me back looking at the records of exploration in Australia, and early impressions of Australia.

The other day, I came across a reference from the 1880s to two early explorers who reported that they had seen the tracks of an animal with a cloven hoof, like a buffalo. (I don't have a picture of this to share, but if you search in Google Images on buffalo spoor, you will soon get the idea.

One of the two who claimed to have fond these tracks was George Grey, who was commonly regarded (with some justification) as an idiot because of his dangerous and stupid decisions, so I didn't take much notice of that.

(That's aside from the fact that I don't have time for explorers who get other people killed, or explorers who, having been abject failures, abuse their power to belittle successful explorers like Edward John Eyre and Charles Sturt. Just take it from me, Grey was both a fool and a swine, though he lacked a cloven hoof.)

Anyhow, today, having had the brainwave that I will come to in a moment, I checked Grey's journal and found this quote from 1838:
… I have still to record the remarkable fact of the existence in these parts of a large quadruped with a divided hoof: this animal I have never seen, but twice came upon its traces.
George Grey, Journals Of Two Expeditions Of Discovery In North-West And Western Australia, Volume 1, chapter 11.
The other report came from Lieutenant William Dawes, a rational and sensible man, but as a First Fleeter who spent something like three years here, he had less chance to realise that what he claimed was an impossibility. Sadly, Dawes left no journal, but prosaic David Collins recorded Dawes' reported find in December 1789.
During his toilsome march he met with nothing very remarkable, except the impressions of the cloven feet of an animal differing from other cloven feet by the great width of the division in each. He was not fortunate enough to see the animal that had made them.
David Collins: An Account of the English Colony in New South Wales, (end of Chapter VIII).
Exhibit 1: Wallabia bicolor track, West Head, Ku-ring-gai
Chase National Park, near Sydney.
Over the years, I imagine a lot of people have puzzled briefly over these reports, muttered something like "well, they got that wrong, then" and moved on. It was just luck that led me to be sifting through my track shots, looking for some to use, soon after reading G. B. Barton's report of the two findings.

Exhibit 1 is the track of a swamp wallaby, Wallabia bicolor, taken close to Sydney on a sandy track.  This is a characteristic macropod track from a hopping beast: two hind feet, each with two toes, side by side.

Exhibit 2, unidentified wallaby track, Wilpena Pound. Can you
see the vague similarity to a cattle hoof?
Exhibit 2 is another wallaby of similar size, but I took this near Wilpena Pound in the Flinders Ranges, north of Adelaide.  This was the shot that made me realise what Grey and Dawes may have seen.

I have enhanced the second picture a bit to make the small toe show up better, but this was the best track I could find one early September morning, a couple of years ago.  Most of the tracks failed to show the small toe, and because I didn't know about the "cloven hoof" theory, I ignored them.

It was just that I had seen Barton's comment two days before I pulled up these shots and now, as I looked at my Wilpena Pound shot, I could see what they must have seen.

Of course there was a great division in the "hoof"—it was really two feet, side by side on ground that was reasonably hard!

A few things that I will come back to: why you should always try capturing animal track shots early or late in the day, how to get them and how to identify the animal that made them.

Friday, 27 April 2012

Sundews


Sundews (Drosera sp.) are insect-eating plants, found in swamps and marshes in much of Australia. Their leaves have sticky hairs that hold drops of protein-dissolving enzymes.

When an insect sticks to a leaf, the enzymes break the insect's protein down to amino acids, and this stimulates the leaf to curl over, slowly, bringing more hairs into contact with the insect, holding it better and dissolving it more.

The process generally takes several hours, so this would be a good case for time-lapse photography.

Gentle people can try feeding a sundew on tiny bits of cheese or meat, but if you are growing a sundew in a pot, you need to grow it in very pure sand, and never add any fertiliser, because these plants won't produce the sticky 'dew' if they can get enough nitrogen and phosphorus from the soil. Don't overfeed them.

Sounds like a science project? I thought so as well.  Congratulations on having such an excellent idea!

There are three other genera in the family Droseraceae: the Drosophyllum of the western Mediterranean, Dionaea, from the Carolinas (USA) and Aldrovanda, described in one of my reference books as "widespread in the Old World".

Here are some things to explore:

  • Do the plants 'react' faster in a warmer temperature? 
  • Do sundews like sugar?
  • How would you find out? 
  • How do different species compare? 
  • There is less protein in cheese: does this produce a slower reaction? 
  • Do they react to small pieces of metal or glass?

Just a note in passing: be careful how you speak. At one stage, I was teaching a bunch of teen-agers who were a bit wild.  We got on fairly well, because I used to be a wild teen-ager myself (more in thought than in deed, if the truth be known, but I understand the mind-set).

Anyhow, one day, I told them I had found some carnivorous plants in the school grounds, and that we were going to leave the classroom to go and see them.

Off we went, and one of the wildest and most switched-off ones was amazingly excited and animated.  It took a while to learn that he thought we were going to visit some cannabis plants!  The good news: he took just as excitedly to the carnivorous plants, finding them food and going back to check them.

There's one thing I haven't worked out yet: why are the leaves often red? Is it some response to its own enzymes, or a defence against them?

Here are some pictures of a few different species.  I need to take some more time to photograph them, but mainly, I need to go out, equipped with a ground-sheet to lie on, given that these things are always in swampy country!

The coin in the first shot is an Australian $2 coin: it is 2cm (0.8") across.
 

Wednesday, 25 April 2012

Seeing inside a shell


This exploration involves making something called an endocast (that means a cast of the interior) of a snail shell. In nature, endocasts can form when a shell or a skull fills with mud before it is buried. Later, ground water sometimes removes or dissolves the shell or bone, just leaving the internal cast.

The real process takes ages, but you can make a much quicker inside cast of a shell by filling it with plaster, and dissolving the shell with acid. Plaster of Paris can be messy stuff, so be careful always to work in the middle of several large sheets of newspaper, and be sure to clean up after yourself. Better still, use a large plastic bowl as your work space.

You also need to talk with an adult about a safe place to leave the acid, and you should get some help in diluting the acid and pouring it. Remember that acid spills are best treated with lots of water, so keep water handy, and work in a place where you can splash water around if you need to.

Get a triangular or flat file, a hand drill with a fine (no more than 2 mm) bit, some snail shells and/or sea shells (try to get some variety!), plaster of Paris, an old yoghurt container, water, an old teaspoon, gardening gloves, rubber gloves, hydrochloric acid, and some safety glasses.
Endocasts of a garden snail shell (left) and a sea snail shell. I had
decided early in the book not to include this project, so I have no

shots of the process to offer, and only this one 20-year-old slide
of the results— and that had to be scanned, hence the quality.

Start by making a scratch at the top of the shell with a triangular file or the corner of a flat file, so the drill has somewhere to grip. Then working very carefully, put on a gardening glove, hold a shell and drill a small hole in the top.

This hole is there to let the air escape when you stuff the shell with wet plaster through the main opening. Drill each shell and test the holes by pouring water into each shell with a wash bottle, then put the drilled shells to one side while you get the plaster ready.

Spoon some plaster powder into the container, pour in a small amount of water, and stir gently, trying not to get any bubbles in the plaster. Mix the plaster and water carefully, until it is about as thick as cream, then try to move any air bubbles to one side, out of the way. Keep adding water until it seems about right; if you add too much water, use a dry spoon or spatula to add a small amount of extra plaster.

When the plaster is ready, use your fingers to push the wet plaster into the opening of the shell until a small 'worm' of wet plaster starts to ooze out the drill hole. Wipe the 'worm' away with a damp tissue and leave the plaster to set. Fill all the shells with plaster, and then go outside and wash the implements you used. Tip the leftover plaster into a hole in the garden or into a container to go in the bin, not down the drain!!

When the plaster is hard, you can put the shells in a beaker (a glass jar will do for this, and so will a plastic yoghurt container), and add some dilute acid. Pool acid or muriatic acid (both are really hydrochloric acid) will be fine, but remember that the acid you buy is strong, so you need to break it down, one part of acid to about nine of water. Strong acid will foam and spit dangerously. As the shell reacts with the acid, bubbles and foam may overflow, so don't fill the beaker more than half-way, and sit the beaker in a large plastic bowl.

For your hands' sake, wear the rubber gloves, for your eyes' sake, wear the safety glasses! With weak acid, you may need to wash out the container and add more dilute acid on the second and third day. Put everything in a safe place (think about pets, small brothers and sisters, unaware adults, wind gusts, and think about what the acid will spill onto if the container tips over).

Wear the rubber gloves when you take the plaster out, once all the shell has gone. What you do now with your trophy is up to you, but you may wish to look, to see if the inside is completely smooth.

Plaster of Paris is a dried-out form of gypsum, which has one molecule of water for every two calcium ions and two sulfate ions, giving us the formula (CaSO4)2.H2O. After you add the water, the plaster forms a solid mass of highly insoluble gypsum crystals, CaSO4.2H2O, with four times as much water, two waters to every calcium sulfate. Plaster expands slightly as it sets, which explains why plaster makes such accurate copies of a surrounding mould. The acid does not affect the plaster, but it does react with the shell, which is mostly calcium carbonate.

You could try making a collection of shell moulds of related species and comparing them, or you could collect some skulls, and make casts of their brain cavities. Hydrochloric acid, diluted with about six times as much water, will take away the hard calcium phosphate of the bone over several days. It is many years since I did this, but three days should reduce the bone to soft cartilage that you can scrape away carefully.

Safety note: unless you are used to handling acid, and maybe even then, give some thought to safety. You need protective goggles and rubber gloves, and anything that has been in acid should be both rinsed and soaked in large amounts of water. Keep pets and small children away!

The technical name for a cast like this is, as I sad at the start, endocast. One of the most important fossils ever found was an endocast of half of the brain of a juvenile Australopithecus africanus, found in the 1920s by (Sir) Raymond Dart. He took one look at the brain cast, and knew that the owner of that brain had walked upright, because he could see where the brain stem left the skull, underneath the brain, rather than at the back! The specimen is often referred to as the Taung baby.

This is a fascinating tale, well worth reading up on. I recommend Lucy: The Befinnings of Humankind by Donald C. Johanson and Maitland A. Edey, Penguin (my edition is 1981).  The ISBN-10 of that edition is 0-14-013935-4.

Monday, 23 April 2012

Twining in creepers: more left and right


Is this twining plant, seen here climbing a
she-oak, right-handed or is it left-handed?
 
This is just a short one, because life is getting a bit hectic: I have a book coming out next week, as I have said before, but I have also launched into something rather different, which has the title Curious Colonists. (Note inserted in August 2013: It actually saw the light of day in October 2012 as Curious Minds.)

I explained the basics of this in My Silence Has a Reason in late February. Yesterday, I drafted The Man Who Lost a River, but that's a side issue, except that it means I'm busy.

Now let us return to our moutons.  Snail shells have two forms, left-handed and right-handed, as explained in Handedness in shells.

Any helix can twist in the same two ways. An ant going up a right-handed helix standing on its end, moves to the right as you watch it, until it disappears around the back of the helix, while an ant going up a similar left-handed helix moves to the left as it crosses the front of the helix.

Ordinary bolts and screws are right-handed, but gas fittings have left-handed threads. There is a good reason for that, relating to safety, which I leave it to the reader to work out.

Every climbing plant must twine one way or the other to get a grip as it climbs. If it twined first one way and then the other, it might unwrap.

Two brilliant British comedy performers, Michael Flanders and Donald Swann, wrote and performed a song called Misalliance. It was about a love affair between the right-handed honeysuckle and the left handed bindweed.

A web search on <Flanders Swann Misalliance> will turn up several versions. To get the original, add the word hat, because the song was featured in a show called At the Drop of a Hat. Here is a link to a Youtube version.

Listen to their song, then wander out into the garden or the bush and look for twining creepers. Check to see which handedness is more common, and see if any species can twine both ways, maybe even on different stems of the same plant.

Footnote 1
Some many years ago, I checked thousands of Australian shells, both on coasts around Australia and Indonesia, and also in the public displays in the Australian Museum in Sydney, where I was working at the time. This was part of a grand scheme for a holiday workshop on handedness.  The dull minds that supervised me could not see the value in this, so in the end, I gave up, in part because I failed to find a single left-handed shell, though I could find tendrils of both handednesses.

Some years later, I was maintaining a general weed-and-pond-life tank and while giving it a clean-up, I realised that the pond snails in the tank, probably introduced with some aquarium weeds that I got from a friend, had left-handed shells.

Why are most Australian shells right-handed, while the northern hemisphere ones are often left-handed?  Could it be Coriolis forces, the ones often invoked when the myth is trotted out about sinks, plugholes and toilets in the southern hemisphere?  (The myth is UNTRUE!!!).  Could it be related to the wat the sun's shadow travels, below the equator?  Our sundials have to be reversed from those used in the north...

I can't really see it, but there's an interesting and very challenging research problem there.

Footnote 2
I am indebted to John Berriman, who emailed me in August 2013 (when I came in and edited a few bits of this) to draw my attention to an article that was published a year ago.  It is S.J. Gerbode, J.R. Puzey, A.G. McCormick, L. Mahadevan, 'How the cucumber tendril coils and overwinds', Science 337, 1087, 2012. As you can see, there is a link to the article in that sentence.

The supplementary material published by AAAS includes movies of tendrils twining which you can see at this second link.

Brainbuster question

How does a plant "decide"?

Sunday, 22 April 2012

Handedness in shells

Most 'snails' have a spiral shell, but not all of them. Slugs have no visible shell, and the shell of a mature limpet is a flattened cone, like an upside-down wok. (A wok, if you do not know what it is, is like a large upside-down limpet.)

Actually, most "spiral" shells are helical, not spiral, but let's stay with the common word.


Left-handed shell on the left, right-handed shell on the right.
(Confession: the left side of the picture is a fake,  produced 
by my digitally reversing the image of a right-handed shell.)
This image has been created from Dover copyright free  art.
Spiral shells come in two kinds, right-handed and left-handed, just like creeping plants (see my next entry when I get around to it). Some of the spiral snails come in left-handed spirals only, some come in right-handed spirals only, and some come in both forms.

The easy way to identify the 'handedness' of a shell is to hold the shell, with the top pointing up, and turned so that you are looking into the entrance hole. If the entrance hole is on the right, the shell is right-handed, if it is on the left, the shell is left-handed.

In one odd example, Sir Theodore Cook (Theodore Cook, The Curves of Life. New York: Dover, 1979), describes a beach at Felixstowe in Britain, where a snail called Fusus antiquus may be found living on the beach, and fossilised in the cliffs behind the beach. Cook said that 99% of the living specimens were right-handed, while all the fossil specimens were left-handed.

Some twenty years ago, I examined several thousand Pacific shells, and several hundred Indonesian shells. They were all right-handed, and so were all the shells on display at the Australian Museum, and the shells of Australia and New Zealand that I examined in several reference books. Even the Australian Museum's fossil shells were all right-handed! I decided to give up my hunt.

Then one day I was cleaning out an aquarium tank. The snails that I kept in the tank to clean the glass were all left-handed! I suspect the snail is an import from overseas, but the lesson here is to never give up looking!

So collect a range of snail and shellfish shells. Sort your shells into species, and into right-handed and left-handed forms (if any). What conclusions can you draw, and why?

While you are at it, look at your snails, and see if you can find any differences within a species. If they are striped, do all of them have the same size stripes? If they have knobs on their shells, are all of them just as knobby, or are some of them smoother? Are they all the same colour?

How could you explain the difference between the fossil Fusus antiquus snails which were left-handed, and the modern ones which are nearly all right-handed? How could such a change be driven by evolution? Right-handed snails go counter-clockwise when mating, and left-handed snails go clockwise, so the two types cannot mate.

If snail species vary in numbers over time, this might explain why a species becomes entirely of one form or the other, just by chance. How could it work across species? Could some predators find left-handed shells easier to attack? Why?

Or could there be another explanation? Maybe the right-handed form has a real advantage, but they used to be eaten by an animal which is now extinct, or the shells dissolved more easily, or the shells of dead right-handed or left-handed animals rolled away into deeper water. See how creative you can be in generating interesting hypotheses.

You can't leave it there, of course. Design a good scientific test which could be used to test your hypotheses.

Helical playwiths
The first man of science was he who looked into a thing, not to learn whether it furnished him with food, or shelter, or weapons, or tools, or playwiths, but who sought to know it for the gratification of knowing.
— Samuel Taylor Coleridge, (1772-1834)
  • Crazy speculation: Martin Gardner ( Ambidextrous Universe, 2nd edition. Ringwood: Penguin Books Australia, 1982) claimed that left-handed shells are quite common. As a North American, he was writing in the northern hemisphere. Could there be a difference between the handedness of snails in the two hemispheres? Could it relate to Coriolis forces, maybe, or the way the sun's shadow goes around a vertical stick? Develop your own hypothesis, and draw up a plan to test it. (By the way, I don't really believe the Coriolis idea. There may be something in the sun theory, but even that strikes me as profoundly unlikely. There isn't a lot to be gained in science from clinging to wacky ideas, but equally, there isn't a lot to be gained from rejecting wacky ideas without savouring them a bit first.)
  • Oddity: There is a television sequence showing an 'alien' being dissected, supposedly back in the 1950s. You can tell that the dissection is a fake, because there is a phone in one shot which has a coiled lead—phones did not have coiled leads in the 1950s!
  • Curiosity, a bit daft at the end: When I first got interested in this question, computer keyboards and telephones all had helical cords, and I found that you could usually deduce the country of origin by looking to see if the twist went to the left or the right. Helical cords are now less common, but look out for them, and see which way they go. Make a study of these leads, and where they were made. See which handedness is favoured in which countries. Does it correlate with the side of the road cars drive on? (Indonesians, Japanese and Malaysians all drive on the left.)
  • Useful line of enquiry: What conclusion should we make from the lack of left-handed shells in the southern hemisphere? There is the basis of a good project here for somebody. Collect information from a wide range of sources, comparing east coasts and west coasts, northern and southern hemispheres. Use real shells, photographs and drawings, and be wary of accidentally reversed images in books and on the web!
By the way, I have a whole website full of science playwiths. It's a bit tired and in need of a good dust and polish—and I'll get there one day, but if you ignore the primitive layout, you may find some amusement there.

It began about 15 years ago when I was teaching computing in a high school, and whipped the first page up for a workshop for teachers from the primary 'feeder schools'. It kind of growed, but the design is putrid.  After all, my web-authoring software was the incredibly sophisticated Notepad!

Final note: the two books cited in this entry were also mentioned in http://oldblockwriter.blogspot.com.au/2012/04/phi-and-spirals.html and I think it is worth having a look at that as well. The next entry looks at twining plants, which are also "handed".


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This blog covers quite a few different things, so I tag each post. I also blog about history, and I am currently writing a series of books called Not your usual... and the first two have been accepted by Five Mile Press, The offcuts appear here with the tag Not Your Usual... . For a taste of Australian tall tales, try the tags Speewah or Crooked Mick.   For a miscellany of oddities, try the tag temporary obsessions. And language us covered under the tags Descants and Curiosities, while stuff about small life is under Wee beasties.



Friday, 20 April 2012

A different ANZAC story


Mehmetciğe Derin Saygı Anıtı
(Respect for Mehmetçik monument)
A closer view of the statue, in one of the Turkish war cemeteries.
In Australia and New Zealand, we are about to celebrate ANZAC Day, the Gallipoli landings of 1915, and the carnage that ensued.  Few nations celebrate a defeat, but we do.  It's an amazing story, and in 2002, I visited Gallipoli, though I will probably never write a book about it.

I should, because there are little-heard stories that deserve telling, like the big Turk who, sickened by the suffering, strode out into No Man's Land to a screaming British soldier.  As the men on both sides saw him and what he was doing, the firing must have stopped.

He picked up the 'Johnnie', carried him gently to the trenches of the invaders, laid him gently down where his own people could retrieve him and care for him, and then turned back to his own lines.

The undeclared cease-fire must have held until he was safely back in a trench, because legend has it that he survived the day.  (Full marks, by the way, to our then Governor-General, who was, by 1967, Lord Casey. He had been there and witnessed the incident, and his1967 description of it inspired the statue.)

Sadly, if there were scraps and tatters of decency, little of that war was glorious.

Just recently, I have been looking into a little-known* versifier called 'Dryblower', because he used to write popular verse in the mould of Robert Service, Rudyard Kipling and many, many Australian bush balladists.  He had escaped my notice until I came across his celebration of the rescue of an Italian gold miner, trapped in an air pocket, deep in a desert gold mine in Western Australia.

The tale of Modesto Varischetti, how a flash flood in a desert trapped him, a thousand feet (330 metres) underground in an air pocket, and how divers were used to rescue him, kept Australia riveted for a week in March 1907, and 'Dryblower' celebrated the rescue in verse.  I wondered who he was.

A bit of digging revealed that Edwin Greenslade Murphy was 'Dryblower'. He was a Perth journalist, and, I quickly discovered, celebrated mainly for a poem written during the Great War, alias World War I, called 'My Son'.  It describes a father's feelings when his son goes off to war.
I have given you unto the Empire;
  You will follow its battle flag;
You will hear the sound of slaughter
  In valley, on plain and crag.
I have taken you out of the playground,
  From many a merry mate.
To send you, a stripling soldier,
  Out to the field of fate.
But when the good work is over,
  And your share of the strife is done
I shall be proud of the lad I lent,
I shall be proud to say that I sent.
             My son,
                          My son.
They have come in their thousands lusty;
  But the gaps still cry for more;
They have come from the bushland lonely,
  From the scrub and the sounding shore;
They have come from the desert dreaming,
  From out of the rolling range,
From the verdant placid pastures,
  From the hills that never change.
From out of the alleys squalid,
  Where the days are drear and dun;
With pride I have heard their footsteps ring,
And so I have sent, to serve my King;
             My son,
                          My son.
They have gone in the teeming troopship;
  They have fought the fight, and fell;
They have felt on their fearless faces
  Draughts from the deeps of hell;
Thinned by the hidden horror.
  Drowned, in the shot-swept blue,
They have closed up the gaps of glory,
  Steadied and thundered through!
And into that mounded country
  Where the deadly work was done,
Where the bloodstained trenches blur and blend
With no wav'ring weak'ning sigh I send
             My son,
                          My son.
Did I fall in a father's duty.
  Did I keep him with mine and me,
How would he face the question
  In the darkened days to be?
Could he walk in such public places?
  Could he do what all good men do
When the patriot women shunned him
  When it came to his time to woo?
If he took not to-day his bayonet,
  His khaki brave and gun,
I would see his brothers in shame abide,
I would see them pass on the other side
             My son,
                          My son.
God of our destined duty,
  Of our Country, Flag, and King,
Keep him in courage lofty
  When the hell-made missiles swing.
And if he must prove an Abel,
  Killed by another Cain,
Give him, O Lord, at parting
  No portion of Calvary's pain.
Let us write over his slumbers
  The glorious words, "Well done!"
For whether our Flag shall wilt or wave,
Let us remember He also gave
             His Son,
                          His Son.
                                           —DRYBLOWER. 
A bit more digging, and I found that this was Dryblower's reflection on his own oldest son, Harry, signing up, and I wanted to know what Harry's fate was, whether he had survived the war.  There was a good chance that early recruits either died, or if they returned, had been maimed for life.

Harry Mansfield Murphy, No. 1018, 32nd battalion, and most probably in C Company, I think, signed on as a drummer, and I thought that sounded like a less than glorious occupation to be the subject of his father's poem, but drummers were still in the front lines, so I didn't write him off.

Then I found that Harry had returned to Australia in July 1916: this usually meant that he had been wounded, but it appeared he was unharmed.  That took a bit more digging, but I found that he became a jazz drummer and xylophonist, and was a sergeant-drummer in a concert party in World War II.

Harry Murphy, Perth Mirror,
28 August, 1926, p. 6.
In 1917, when Harry was drummer in a recruiting band, he was identified both as a returned soldier and an 18-year-old.  Like many others, he had falsified his age, and his proud father had stood aside as a 16-year-old went off to war.

Harry is quite widely documented (by me) in the Trove historic newspapers collection, so readers who wish can find him by looking for the tag <Harry Mansfield Murphy> (or just use this link).

You will find conflicting information: one contemporary account refers to him going on patrol in 1916, but a later story, written in 1935 by somebody who served with him, claimed that he was sent back from Egypt when his age was discovered, and that he never saw active service—but his father had approved of his joining up.

That's why I don't write military history any more.  I did, once.  My Kokoda Track: 101 Days was a basic and slightly simplified telling of a riveting story of the time in 1942 when two threadbare, unsupported, ill-equipped militia battalions held off a far larger Japanese force, long enough for seasoned troops to be brought into the line, and in the end, to force them back into the sea.

There was another tale, one that I muted, a story of bungling stupidity by the Brass.  It dominated the first draft, which I threw out.  Because my own minimal military experience was survived by emulating Jaroslav Hašek's Good Soldier Švejk (with traces of Yossarian), there was a human note to what I wrote in my second draft.

I didn't glorify war, but I gave an even-handed account, and that interested another of my publishers, who immediately asked me to do a particular campaign for him.  I gently declined, on the ground that when you do military history, you meet with an  awful class of people.

I prefer not to celebrate a world in which fathers could watch proudly as their 16-year-old sons went off to war, not bewailing the fact, but exulting over doing duty to country, flag and king.

The poem continued to live on, after the war, and after Dryblower's death in 1939, though the only copies I can find on the internet come from old newspapers of that era, three in Australia and one in New Zealand.  Well, I have changed that, by putting the clean text online. [Post script: I have since come across a clean version from the West Australian Bush Poets.]

The watchword of ANZAC Day is 'Lest We Forget', but equally, we should make sure we don't forget the butchery and the madness of war, especially the madness that allows a man to urge his first-born on to seek death or glory.  I won't write about it.

But I have a responsibility to write of it.

* Note added May 7: I have amended my description of 'Dryblower' from "lesser" to "little-known", after a W.A. bush poet sent me some of the 'Dryblower's' other stuff.  I now concede that I was judging 'Dryblower' by what appeared in the daily press.  This was often stuff penned on the spot to plug a gap in a page. After reading Going East (1903), I declare him to be an excellent poet. To see some of his other poems, use this link.

Note added, April 2015: I have just added an account of the first Anzac Day, held in October 1915, and pinpointing the second, on April 25, 1916.

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This blog covers quite a few different things, so I tag each post. I also blog about history, and I am currently writing a series of books called Not your usual... and the first two have been accepted by Five Mile Press, The offcuts appear here with the tag Not Your Usual... . For a taste of Australian tall tales, try the tags Speewah or Crooked Mick.   For a miscellany of oddities, try the tag temporary obsessions. And language us covered under the tags Descants and Curiosities, while stuff about small life is under Wee beasties.




Thursday, 19 April 2012

Entry number 100

A small celebration is in order, methinks.

Here is the first review of my new book, Australian Backyard Naturalist, which will be released in ten days from the date of this post.

The nice people at Needtoreadthis created the review to be found in this link, and which I will quote from below: the clever reader may be able to detect that I'm delighted with the comments.

... a fantastic collection of facts, photos, illustrations and projects, as well as notes from the authors own experiences ... 
The graphic design is varied and interesting with no large chunks of text to discourage reluctant readers. Photos of deceased animals and close ups of fly eyes and maggots, as well as the array of fun facts will keep children turning the pages. The projects are user friendly and include checklists and easy to follow instructions using mostly every day materials.
At 222 pages it is a substantial resource for a classroom or library. It would make a lovely gift, especially for boys. My own sons were quick to grab this from the pile of review books and anything that encourages them to get away from the computer screen and discover nature is a hit with me!
 I think the reviewer worked out what I was trying to do, though given that my grand daughter is the biggest fan of praying mantises that I know, I'm hoping girls will be given copies as well!

That's enough about me, though, because I am aware that many of this blog's readers are from outside Australia, and this book is only being released in Australia at this stage.

Monday, 16 April 2012

Phi and spirals


This gets a bit more complicated, but it is still possible to play with this, without too much brain work—it's all about perception.  Still, we decided to leave the mathematical bits out of a book where they might discourage some readers from the main message, which is that poking around nature is fascinating.

The golden mean, or golden ratio, was known to the ancient Greeks. This is a number, represented by the Greek letter "phi", which can be defined as a number which, when you take one away, is its own reciprocal. In algebra, if you understand that, (phi-1) = 1/phi.

A few quick trials on a calculator will give you a value of about 1.618 for phi: if you try, you may even get a better value than this. A line can be divided to make two segments, A and B. If the division is at the "golden ratio" point, then A is to B as A + B is to A. In mathematical notation, A:B = (A+B):A. The Greeks used the golden ratio quite a lot in architecture and art, and so do we: modern televisions and monitors have an 8:5 ratio, which is 1.6, very close to phi.

The curious thing is that phi can be used to draw a spiral. Not only that, some of the most beautiful spirals in nature seem to be based on phi as well. Snails and sunflowers cannot do complicated arithmetic, but the "phi" pattern is there for us to discover in the snail's shell, or the sunflower's seeds.

Here is how to draw an approximation of a logarithmic spiral with just a straight edge and a pair of compasses. Draw the lines first, and then add a series of quarter circles as shown.

Start by drawing a large rectangle with a phi ratio for the two sides: try 18 cm by 29.1 cm, which just fits on an A4 page.


Draw a square (18 cm x 18 cm) at one end, and you will produce a smaller golden ratio rectangle at the other end.

Turn the paper 90 degrees, and make another square. Keep turning the same way, drawing smaller and smaller squares in the same way, and then use a pair of compasses to join the matching corners as shown in the sketch.


Each curve is part of a circle, but the result is very like a proper logarithmic spiral, like the one you can see in a nautilus shell, or in a fossil ammonite, like the one above, which I bought in Morocco, last May.

(A tip for would-be fossil buyers in Morocco: these ammonites are very common, cheap as chips and hard to fake, so they will typically be the Real Thing. Buy one of these as soon as you can and get used to its feel—and the sound it makes when you tap it with a fingernail.  Then, when somebody tries to sell you a trilobite, you are more likely to notice the differences between stone and resin castings.  Sadly, most of the trilobites that you will be offered, especially the fancy ones, are fakes.  There are a couple of photos of a poor-quality fake in my blog entry Simulating a fossil part 1.)
Some amusements

* The Fibonacci series (1, 1, 2, 3, 5, 8, 13, 21 . . . covered in the last entry) can be used to generate phi. Just divide each successive term of the series by the term before it to get a set of numbers that converge on phi. Try any other "cumulative series" beginning with any two numbers, and see what happens. (Two examples to investigate: Lucas numbers and Q numbers.)

* Search around for information on the "golden ratio" or "golden mean", also called "tau". You could also look for information about a Greek artist called Pheidias, who was interested in phi.

* The logarithmic spiral is the only spiral which does not change its shape as it grows: does this explain why the spiral is so common in nature? Can you see a link with fractals?

* Can you use a cumulative series, Fibonacci or your own, to draw a spiral?

Just to prove that the age of the book isn't quite over, here are two references: (Sir) Theodore Andrea Cook, The Curves of Life. New York: Dover, 1979 and Martin Gardner, Ambidextrous Universe, 2nd edition. Ringwood: Penguin Books Australia, 1982.)

I pick up this theme again in Handedness in shells.


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This blog covers quite a few different things, so I tag each post. I also blog about history, and I am currently writing a series of books called Not your usual... and the first two have been accepted by Five Mile Press, The offcuts appear here with the tag Not Your Usual... . For a taste of Australian tall tales, try the tags Speewah or Crooked Mick.   For a miscellany of oddities, try the tag temporary obsessions. And language us covered under the tags Descants and Curiosities, while stuff about small life is under Wee beasties.


Phyllotaxis and shade


Have you ever wondered why you can get such good shade under some trees in summer? Gum trees are less shady because their leaves hang down on edge, avoiding the hot sun, but other plants arrange their leaves to catch as much sun as possible. When they do, a remarkable mathematical pattern emerges, and once again, it often involves the Fibonacci series.

Now we have had a mad fad for The Da Vinci Code, I probably don't need to explain this, but I will.  The Fibonacci series was first worked out in a text book on the "new" Arabic numerals, and turned up in a worked calculation on breeding rabbits.  Look it up if you need more.

The series goes 1, 1, 2, 3, 5, 8, 13, 21, 34 ... where each term is the sum of the two terms before it.  It has interesting mathematical features, but is is also interesting because it turns up quite a lot in nature. In this entry, I will deal with plants, just briefly.

When you look at the leaves coming out of a stem, they often form a spiral pattern. Choose a leaf near the bottom, and give it the number 0. Then number the leaves up the stem in order until you come to one that is directly above leaf zero. This will usually be leaf 5 or leaf 8.

Then if you count the number of times an ant would go around the stem, walking from the first to the last leaf, the number will usually be the previous Fibonacci term (3 or 5). The ratio 3/5 or 5/8 is called the phyllotaxis of the plant.

What you do with this is up to you. There must be a good practical reason for the way the Fibonacci numbers bob up, but what is it? And do different species in the same genus (or in the same family) have the same phyllotaxis?

Incidentally, if you look at the number of petals on a flower, the number is very often a term in the Fibonacci series. I have an idea about why this might be, but I will only say that Goethe would probably have agreed (that's a weird hint which is probably no use at all!). You work it out!

This theme continues in Phi and spirals.


Saturday, 14 April 2012

Collecting bones



Easy choice: You can always go and collect bones in the bush, but they will usually be scattered by scavengers.

My children (they are grown-up now and still talk to me) helped me round up these wombat bones from a 50-metre radius of the actual death spot, which we identified by finding a fair number of bones and teeth in one place, along with some hair and fur.

We carried the other bones back to there. Look carefully for the tooth near the bottom of the picture: no scavenger bothers to carry teeth away.

In some parts of eastern Africa, geological deposits of the past few million years can be reliably dated by searching for pig teeth, because an expert can identify a pig tooth down to an actual species, with a known date range.  To the biologist, teeth can be very interesting.

This kangaroo was probably a roadkill, found just off the road in the Margaret River area of Western Australia.
This shot appears (reversed) on page 6.

At the time, I was looking for lizards and wild-flowers, and keeping a wary eye out for snakes.


Be careful where you collect bones, because even collecting dead bones can be risky!

This dugong mandible was on Thursday Island, in a place set aside for butchery, ad the remains attract sharks when the tide is in, and crocodiles all the time.


At the time, the tide was out, so we were half-safe, but that's not really enough, so it;s better to do your own bone-cleaning at home or near home, where the risks are less.

What you need: A dead vertebrate (birds and mammals are the easiest, reptiles can be harder to work with, and snakes have very fiddly ribs). There are lots of ways to clean away the meat, so read the details below, and make up your own list of needs.

Let;s stay now, for a while, with this exercise that didn't make it into the book, because I took short-cuts: I was about to go to Western Australia (where I got the kangaroo above), when I found the bandicoot seen here, on September 1.

This shot was used in the book, in the flies chapter, page 89.
I moved it off the track where I found it, and weighed it down with a couple of stones. If you click on the picture to see a larger version, you will see that the ants were already moving in.

It was four days before I could get back, and by then, the flies were there in force.

You have to be a little bit tough in this sort of job.  I used tolls, sticks, and where necessary, bare hands to get the body into a wire bag. I strongly recommend taking gloves!

You cab see the main tools here: a bag made from a folded-over piece of chickenwire, fine-nosed pliers and medium-gauge galvanised wire.

Just stitch the dead animal in like this, but being wise in rerospect, it would be a good idea to contain it first in a fly-wire bag, or if you can't do that, leave a flat board and rocks over it, to fend off large birds!












 You see, the problem was that while I had my bag tethered to a tree, something, probably crows (Australian ravens) came and pecked through the wire, smashing the bones and ripping most of the bits out.

When I came back from Western Australia and hurried out to the site, all I had left was one forelimb, a shoulder-blade and part of the cranium (skull), plus a bit of fur, and a failure that couldn't go in the book.


Still, it's good enough to go here, if only to show you what not to do!   If you ignore my warnings, you will end up with a poor showing like mine.  Trust me, there are better ways to do it!


In museums, bones are usually cleaned by the larvae of dermestid beetles, often referred to as "museum beetles". The grubs eat all the flesh from the bone without harming any bone parts. They are really useful if you want to preserve the fine bone structures in the nose area of a mammal skull.

There is one drawback: museum beetles can get loose and attack stuffed animals, insect collections and other precious items. Around the home, they may eat your shoes, bags and belts!

Some people enjoy cleaning and mounting a skeleton for display. This often means using sharp knives and dangerous solutions—and handling smelly things. If you are young and want to try this, get advice at each stage, because you may be at risk, pets and younger children may be at risk, and the smells can definitely upset adults.

The first task, if you want to prepare a carcase yourself, is to get rid of the excess skin and meat. Cut away as much of the flesh as possible, making sure that you don't scratch the bones. Take care also that the ligaments, the strings that attach bones together, are not cut, so you know what goes where.

Young readers: if you are using a knife, seek adult advice on safety first: simple things like always cutting away from yourself, and using a cutting board—and don't use the best board in the kitchen to slice up a smelly dead animal! If you have a digital camera, take lots of shots from different angles so you can see later how the bones connect.

You can clear the rest of the meat from larger animal bodies by burying them (if possible, 'sewn' with copper wire into a piece of plastic fly-screen to stop large animals eating the whole body). Mark the spot with a stick so you can return for the bones at a later date. Small dead mammals such as mice will be clean bones and skin scraps after two or three weeks if they are stapled into a small fly-screen bag, and left under a small amount of leaf litter in a damp place, or even under a board and rocks.

While that has worked for me in the past, I recommend putting that in a chickenwire wrapping or bag. To stop scavengers carrying the bag away, wedge one edge of it securely under a rock or pin it down with a spike. Better still, surround the bag with bricks and put other bricks over the top leaving tiny gaps that keep larger animals out but still let the small animals in. You can also tether the bag to a tree: I recommend doing this.

Older tadpoles can also do a good job of cleaning up a skeleton, but you need to change the water every day. Small fish are more effective.

Warning: boiling, which you will see recommended, is slow, it scatters the bones, and often shrinks the bones slightly. Older books often suggest using "sulfurated potash" (potassium sulfide). This is a fire hazard which causes toxic fumes, so if you have a book that suggests this method, try another book, fast! Older books may also suggest using carbon tetrachloride or benzene to get rid of the grease. In one word, don't, because these chemicals are dangerous!

If you want to display the skeleton later in a life-like pose, you can leave the ligaments in place, thread a wire down the spine, and use wire to support the skull at the end of the spine, but you need to decide early, and plan ahead. Take photos and put tags on some of the larger bones. Write notes on sheets of paper to put under the bones when you take photos.

You can leave the skeleton in water for several days, then brush the remaining meat away with an old toothbrush, leaving the ligaments in place. To remove the ligaments, soak the skeleton in dilute sodium hydroxide solution in a plastic bucket, but take the bones out as soon as the ligaments come away. You will need gloves and goggles and somewhere safe to leave the bucket. Get advice!

Bones can be bleached in hydrogen peroxide or in any household bleach, but they need to be de-greased first, and that means using nasty chemicals. It's better to leave the bones unbleached. Most museum skeletons still have their natural colours. You can reduce the smell by putting clear varnish on the bones, but this spoils the look a bit.

Larger skeletons should be fully separated and rejoined with wires. Just drill small holes near the ends of the bones and thread fine wire through. You can learn a lot by going to a museum and looking to see how professionals do it. Smaller mammals such as bats can be mounted on a piece of varnished board, using an epoxy glue such as 'Araldite'.

You can also try collecting the bones from a cooked chicken and reassembling them, but you will usually end up with a headless chook that has no feet.  (If you aren't Australian, look chook up, or think about it for a moment.)


Monday, 9 April 2012

Storing dead specimens


There is a time and a place for taking animals, killing them and storing dead specimens, but as a rule, I think it's best to leave things where they are. I will find them, catch them if I really need to, but where possible, I try to let them go where I found them.

Flinders ranges dragon: note its camouflage.
I have a few dead animals in Australian Backyard Naturalist: one was a mummified lizard that I found in my garage; another was a freshly dead bandicoot which will appear in the next blog entry in a starring role.



Notice the pattern there: I collected them dead. There was also a huntsman that I found dead: I suspect that somebody had sprayed it, because it was freshly dead and undamaged.  I will come back to that in a moment.


Under normal circumstances, when I found a dragon like the one on the left, I would leave it where it was, photograph it (as I did), and walk off.

In this case, I was with a party in the Flinders Ranges who would be interested, and I needed a close-up shot taken it show how a lizard is held safely, gently and firmly (that's safe for the lizard: you can't see the tail in the lower shot, because it's being used to lash me!

Under normal circumstances, this next shot is far nicer than a dragon in a cage or in a pickling bottle!
One of our local water dragons in Sydney.
Would you believe that this was a dead cicada, found on a path?  Well it was!

There are times when it is right and proper to collect live specimens to kill and store for reference or study purposes. If you end up working in this area as an adult, then you will spend a great deal of time catching and preparing specimens. As a hobbyist like you, I urge you to just collect with care and thought. Here is what can happen when collectors go mad.
Hunting the last great auk
We know a great deal about the last of the great auks. These Icelandic sea birds were collected to death, so poor hunters could sell the bodies to rich "amateur" collectors. A set of islands called the Geirfuglasker Skerries, sank after volcanic activity in 1830. This left the auks with just a single home, the island of Eldey, off Iceland. The collectors kept collecting.
On June 3 1844, an expedition of 14 men sailed to Eldey. Sent by an Icelandic bird collector named Carl Siemsen and led by a Vilhjälmur Hakonarsson, they wanted to get specimens before the last auks died out.
Only three men actually landed on the island: Sigurör Islefsson, Ketil Ketilson and Jón Brandsson, and they only found two great auks. Both birds ran away, but slower than a man could walk. Jón cornered one of them and Sigurör trapped the other. Ketil walked back to the place where the birds had been, and found an auk egg, but it was broken, so he left it there.
The last great auks left Eldey dead. Vilhjälmur Hakonarsson went back in 1846 and again in 1860, but he saw no great auks on Eldey. A species had been snuffed out in the name, not of science, but to feed an amateur mania for unusual and rare specimens.
Sadly, I couldn't get an auk to come to the camera, but here are some puffins from Lunga in the Hebrides.
If you are collecting lots of moths or butterflies, you will need a relaxing jar, a spreading board, storage boxes and entomological pins, but I won't deal further with those here, because I have little experience with them. I can, however, discuss relaxing as I practised it on my dead huntsman spider.

When thing die, muscles tighten, the body contorts, and it generally ends up drying into a contorted shape. The spider was beginning to contort, so I put it in a jar that contained a wet tissue and a piece of aluminium foil. Sorry, I wasn't planning to write about this in the book, so I didn't photograph the jar.

Anyhow, the idea was to keep the spider in 100% humidity until it became loose, so I could then pin it into place on a piece of foam like this. None of the pins goes through the spider: they all just hold the limbs in place while it dries and "sets".

Notice how the pins support and constrain the limbs, so they dry and set in a like-like pose.
You can keep dead insects, pinned in drawers or boxes, but if you want to preserve them, you will need to seal the containers and keep some mothballs in there, or other insects will eat your prizes. Another possibility is to use a preservative solution.

The most common solution is 70% alcohol, a mix of 70 mL of alcohol (methylated spirits) and 30 mL of water (scale this up or down, keeping the proportions constant). Over time, some of the alcohol will evaporate, so if you need to keep your specimens for a long time, you need to pour off all the liquid and replace it every couple of years.

Some specimens slowly bleach over time in 70% alcohol, but I cannot say if this is caused by light or the fluid. One drawback with methylated spirits: it contains some poisons to stop people drinking it, and when you add water, it often goes cloudy for a while, but after a while, it goes clear again.

Photographs are probably a better way to record your finds. Just ask this centipede, which I brought inside and then released under its flower-pot where I found it.

Anybody who knows my Facebook page will recognise this beastie.



Sunday, 8 April 2012

Making a Secchi disc

Some years ago, I was researching a book on the way science changed in 1859, the year that Charles Darwin published On the Origin of Species.  In many ways, 1859 was an annus mirabilis, a year of miracles, and one of the threads I pursued was the matter of weather observation and weather forecasting.  This science had been gathering pace during the 1850s, and really came into its own around 1858–1860.

That was when I came across a well-known name, but in an unexpected context. First, I learned that the scientist I knew only as Secchi, who invented the Secchi disc, was Angelo Secchi, but more than that, he was Father Angelo Secchi.  He was a Jesuit priest who had been made director of the observatory at the Collegio Romano at the Vatican in 1849, after two years studying physics at Georgetown, Washington D.C.

By 1859, he had made the interesting observation that there were "atmospheric waves".  Think of the situation where a "high" moves.  It was this movement that Secchi said could be detected.  He added that these waves could travel from Rome to London in about 36 hours.

He is remembered today for suggesting the classification of stars by their spectra and for his Secchi disc, used to assess turbidity (if you like, you can say in water.  I have to confess that I knew him only for the Secchi disc.

Turbid water, muddy water, is a problem for living things.  Plants need light to grow, and all animals depend, directly or indirectly on plants for food.  The problem in the 19th century was to find a reliable way of comparing turbidity in water.

Creating a scale was too hard, but at least, with a Secchi disc, you can get a comparative measure of different turbidities.  One lot of water, you can still see the disc when it is three metres down, but in muddy water, the disc may disappear when it is only 10 or 20 cm below the surface.
The completed Secchi disc. home-made variety, Mark I and only.

The basic idea was to lower a standard object (the disc) into water until it just disappeared, note the depth at which the happened, using marks on the line with which it is being lowered.  Then as a control, the standard object is lowered further, and then hauled in until it is just visible.  Once again, the depth is measured, the two depths are averaged, and there is your turbidity measure.

There are a few catches there: you need to have shade over you to cut out dazzle that might make it hard to see the disc.  An umbrella is good for that: look to the right.

And in shallow water, you may need to use a mirror on a stick, like the illustration on the left-hand side.  Just improvise as you see fit!


People looking for science projects: think about comparing the animals and plants in turbid water and clear water. It won't be easy, but you will most certainly need a Secchi disc, and as they are hard to buy, it is easier to make one.

You need an old paint tin lid (or something similar), a drill, a ring-bolt, some string, and either a pen or some bits of cloth to mark the depths.

I made mine many years ago by drilling a hole in an old paint tin lid that I had painted white. I spray-painted two quarters of it black before drilling a hole in the middle before fitting a ring-bolt in place.
The red colour just happens to show
that the lid came from a 4-litre (or
1-gallon) paint tin. Only the black and
white pattern on the top matters.

While the official design (see the diagram on the left) has a dangling weight below the disc, I found that all I needed to do was put a couple of extra nuts on the base, and everything worked perfectly.  You can see those on the right.

Then I tied some reliable twine to it, with pieces of coloured rag tied into the line as reference markers, one at each metre from the surface of the disc. You can vary this design as you wish.