MV Blog

DISPLAYING POSTS FROM: Apr 2014 (9)

Why we can't give a stuff

Author
by Alice
Publish date
29 April 2014
Comments
Comments (1)

The Discovery Centre receives heaps of enquiries from budding enthusiasts eager to learn the art of taxidermy – it’s no surprise because Museum Victoria holds the largest collection of taxidermy mounts in the state.

behind the scenes Rows of taxidermy mounts hidden behind the scenes of the Melbourne Museum.
Image: Alice Gibbons
Source: Museum Victoria
 

Taxidermy is but one of many tasks performed by the multi-talented members of our preparation department. The preparators work purely on museum projects, combining skills in taxidermy, moulding, casting and model-making to enhance the state’s collections and research.

reptile moulds Reptile moulds and casts hand made by the preparation department.
Image: Alice Gibbons
Source: Museum Victoria

 

Seal model Sculpting and modelling a seal for permanent display.
Image: Alice Gibbons
Source: Museum Victoria
 

Only a fraction of the work that the preparation department performs makes its way to the public displays, with the majority of their work residing behind the scenes. Most animals coming into the museum join the research collections and don’t need to be prepared as life-like mounts; 90 per cent of the specimens prepared at the museum have data and tissue samples collected and are preserved as study skins and skeletons. These specimens become priceless tools in assisting scientists identify and compare new species, better understand the evolution of species over time, and research how we can conserve our fauna into the future.

Study skins Study skins used in the research collection.
Image: Alice Gibbons
Source: Museum Victoria
 

Skeletal remains Skeletons prepared for the research collection with the assistance of dermestid beetles.
Image: Alice Gibbons
Source: Museum Victoria
 

Due to the busy workload of our preparators, we are unable to provide personal advice to individuals about taxidermy. We are, however, bringing out our experts for the next Smart Bar to focus on the history, methods and tools of the craft. This Thursday 1 May, from 6-9pm our experts will explore the inside story of taxidermy with pop up talks and demonstrations.

Koala moulding Tools and measurements used in making a koala cast.
Image: Alice Gibbons
Source: Museum Victoria
 

exhibition maitenance Ongoing maintenance of exhibition material such as this interactive component from Think Ahead is a large part of the preparation departments workload.
Image: Alice Gibbons
Source: Museum Victoria
 

For those unable to attend, there is plenty of information available online through supply websites, online tutorials and forums. Commercial taxidermists can also be found in the Yellow Pages, and you may be lucky enough to find one who is willing to discuss their tricks of the trade. Formal tutelage in taxidermy is almost non-existent in Australia but getting involved in online forums and clubs is a great starting point to meet likeminded people and gain expert advice. Most of our preparators started out reading taxidermy books for beginners, many of which can still be found in local libraries.

Keep in mind that in Australia there are strict licencing protocols surrounding practicing taxidermy on native animals. For more information visit the Department of Environment and Primary Industries website.

Links:

Smart Bar: Stuffed

So many specimens

Bugs within bugs, part 1

Author
by Patrick
Publish date
28 April 2014
Comments
Comments (1)

To support our collection of almost 100 invertebrate species on display at Melbourne Museum, Live Exhibits staff must occasionally collect bugs from the wild, and some of these can hold unwanted surprises inside.

Chalcid w A Chalcid wasp, newly emerged from the cocoon of its host caterpillar.
Image: Patrick Honan
Source: Museum Victorai
 

At least one in every ten insect species is a parasite on other insects. In Australia this adds up to several tens of thousands of parasitic insect species, all living their lives on the outside or, more commonly the inside, of other insects. Most of these parasites are wasps and flies, and most of their hosts are butterflies, moths and beetles.

Tachinid fly eggs on beetle Tachinid fly eggs on the outside of a doomed Leaf Beetle larva (Paropsis species).
Image: Patrick Honan
Source: Museum Victoria
 

Parasitic insects usually lay their eggs directly onto or into the body of their host, but may lay eggs on a food plant in the hope that they will later be ingested by a potential host. Once inside, the parasitic larva consumes the host’s internal tissues while the host continues to go about its business. The parasite usually avoids the vital organs until the last minute – then polishes these off and finally kills its host.

Aphid ‘mummies’ Aphid ‘mummies’ – aphids that have been parasitised and glued to the leaf by Braconid wasps. When fully developed, the wasps will cut a perfectly circular hole in the back and emerge as adults.
Image: Patrick Honan
Source: Museum Victoria
 

Parasitic wasps are able to find their hosts no matter where they might hide. In order to lay eggs on its host – Sirex Wood Wasp (Sirex noctilio) – Megarhyssa (Megarhyssa nortoni) can drill through 9cm of solid wood with its ovipositor (egg-laying organ). Megarhyssa females find their hosts using infrared detectors on their antennae; the outer bark of a tree is 0.5oC warmer where a larva lies underneath.

female Megarhyssa A female Megarhyssa (Megarhyssa nortoni) drills through a pine tree to deposit an egg on the Sirex Wood Wasp within.
Image: Patrick Honan
Source: Museum Victoria
 

A parasitic wasp will sometimes inject venom that paralyses the host but keeps it alive, allowing the wasp to hide it away for its offspring as a sort of living larder. A large wasp dragging a larger, paralysed, huntsman across open ground is a familiar sight during summer.

Pompilid wasp drags a huntsman A Pompilid wasp drags a huntsman (Isopeda species) from its hiding place under bark, before paralysing it and inserting an egg.
Image: Patrick Honan
Source: Museum Victoria
 

A caterpillar can sometimes dislodge a parasite’s eggs with its mandibles, but wasps usually lay their eggs just behind the caterpillar’s head where they can’t be reached. Many hosts are able to ‘encapsulate’ a parasite already inside their bodies, localising its damage and starving it of oxygen. When more than one parasite is laid inside a host, the larvae fight to the death within the host’s body for the rights to its organs.

wasp cocoons inside the empty shell of a Cabbage White Butterfly caterpillar Thousands of parasitic wasp cocoons inside the empty shell of a Cabbage White Butterfly caterpillar (Pieris rapae). Each cocoon will soon produce a tiny wasp that flies off to find other caterpillars to parasitise.
Image: Patrick Honan
Source: Museum Victoria
 

Parasites are themselves subject to attack from hyperparasites, insects that lay eggs inside an already-occupied host. The emerging larva seeks out the parasite in residence and burrows into its body. These in turn may be parasitised by superhyperparasites, and so on.

“Great fleas have little fleas upon their backs to bite 'em,

And little fleas have lesser fleas, and so ad infinitum…”

Augustus de Morgan (after Jonathan Swift)

Cork Colosseum x-ray

Author
by Kate C
Publish date
17 April 2014
Comments
Comments (0)

An x-ray machine usually employed for mammography examined an unconventional patient earlier this year: a model of the Colosseum made from cork around 1800. Thanks to generous assistance from Lake Imaging in North Melbourne, object conservator Sarah Babister now has a view inside one of our most curious objects.

Four people discuss photograph Conservators Sarah and Dani show radiographers Jeff and Ghazia a photo of the Colosseum model.
Source: Museum Victoria

cork Colosseum model The facade of the Colosseum model. (HT 24386)
Source: Museum Victoria
 

Radiographer Ghazia adjusted the settings of the mammography machine to accomodate this unusual material—cork is much less dense than human tissue—and produced wonderfully clear and informative images of several pieces of the Colosseum.

Woman with x-ray machine Ghazia placing a piece of the Colosseum on the mammography machine.
Source: Museum Victoria

Woman with computer Ghazia adjusting the levels of the x-ray to best show the hidden structure within the cork Colosseum.
Source: Museum Victoria
 

We think that our Colosseum was built by English model-maker Richard Du Bourg (or Dubourg), but in the absence of a signature, Sarah is looking for characteristic materials and construction techniques that could confirm its maker. Further research by historian (and the museum’s Head of Humanities) Richard Gillespie and genealogist Neil Gill is fleshing out the intriguing story of Du Bourg and his models; Richard recently visited similar objects in overseas collections for comparison. Sarah and Richard will present a talk about the model and its story next month as a part of the History, Cultures and Collections seminar series.

From 1775 to 1819, Du Bourg’s models of classical ruins were the height of fashion and his a well-known London exhibition. “He’s a fascinating character,” says Sarah. Notoriously, his working model of Vesuvius destroyed an entire exhibition when its eruption set fire to all the other models on display. “He lived until he was in his early 90s and even though he’d been very famous he was living in poverty.”

Sarah explains that cork models “were really popular at a certain time and were kept as tools to teach students. Then they fell out of fashion and a lot of them were disposed of.” This may explain Du Bourg’s impoverished old age, and is the reason why the museum has this model at all – in 1929 it was sent from the Science Museum in London to the Industrial and Technological Museum in Melbourne.

cork Colosseum detail Sarah holding a large piece of the Colosseum model.
Source: Museum Victoria
 

The model is over a metre wide and in poor condition. The base it sits on is cracked and the gesso applied to the perimeter is flaking, and several sections of wall have broken off. These broken sections are a mixed blessing, since without them there could be no x-rays, which reveal the lead pencil marking lines, and pins and nails used to hold the pieces of cork together. This information may help confirm whether Du Bourg made the model, but will also help Sarah reattach the broken pieces.

X-ray image of a piece of the cork Colosseum X-ray image of a piece of the cork Colosseum. The metal pins, and decorative carvings covered in lead paint, appear white.
Image: Lake Imaging
Source: Museum Victoria
 

“Most of the pieces are there so the model would be virtually complete with the exception of a few small columns which might need to be replicated,” she says. “I’d love to put it back together so it can be viewed how it should be viewed because it’s such an amazing object. The level of detail in the carving is wonderful, and cork lends itself so well to representing that ruinous state.”

To learn what the x-rays revealed, come along to Richard and Sarah's free seminar on 14 May, titled For the Nobility, Gentry & Curious in General: Richard Du Bourg’s Classical Exhibition, 1775-1819.

Links:

Cork Colosseum model on Collections Online

Full moon funnies

Author
by Meg
Publish date
16 April 2014
Comments
Comments (0)

Last month I was asked if the museum experienced a spike in the number of “unusual” (read “weird”) enquiries during a full moon. My initial reaction was to dismiss this theory as light-hearted superstition – then I stopped to think on it for a bit… and my subsequent reaction was to dismiss this theory as light-hearted superstition. However I also resolved to undertake a simple survey of the enquiries database to see what the cold hard stats had to say about it.

 

Close-up of Planet Earth with Moon in background. Close-up of Planet Earth with Moon in background.
Source: NASA
 

The “lunar effect” phenomenon – the belief that the lunar cycle influences human behaviour – remains a significant feature of some human cultures, present as far back as the Ancient Greeks and Romans, and even earlier, through to modern adherents to the Wiccan tradition, or Neo-Paganism more broadly.

It has long been suspected that the moon and its phases have an effect on mental health – indeed the term “lunatic” is derived from the Latin lunaticus, “of the moon.” Lunar effect mythologies include, for example, lycanthropy (werewolves), increased fertility and birth rate, and weather events and natural disasters, among others.

So what of the lunar effect on museum enquiries?

On each of the four full moons so far this year Discovery Centres took an average of 22 new enquiries for the day, of which one, or two at the very most, might be broadly categorized as unusual. On the full moon of January 16, we received a comment about one passenger’s recollection of a man-overboard incident that occurred during his migration to Australia on board the Johan Van Oldenbarnevelt, and a question about the significance of the role of thongs (what???) in nineteenth-century Victorian construction. Meanwhile, during the full moon of March 17 we were contacted for advice by the concerned owner of a French bulldog who had been the unfortunate victim of a scorpion attack in the bad ‘burbs of Adelaide. Outside of these, the rest of the enquiries were pretty standard fare: image requests, spider identifications, tractor donations, etc…

On the full moon of February 15, however, we did receive three [spam] emails in a row offering heavily discounted supplies of Viagra – suggests there may be some truth to the fertility claims?  

Death by coitus

Author
by Alice
Publish date
14 April 2014
Comments
Comments (0)

The other week I attended Isabella Rossellini’s comic and educational monologue Green Porno, a fascinating lecture on the sexual escapades of the natural world. It really got me thinking about the various and bizarre methods of animal reproduction that I've encountered since commencing my role at the Discovery Centre. We see an intriguing array of specimens brought in to be identified and in some cases even added to the collection. Many of these animals would be well-deserving of a feature episode on Isabella’s show, but none have captivated my attention more than our recent acquisition of a male phascogale. 

Phascolgales belong to the same group of marsupials as the Tasmanian Devil and the quolls. But unlike their relatives they have managed to keep a very low profile. Considering that male phascogales live fast, die young, and have such a frantic sex life that it kills them, I was really surprised that the first time I became aware of this genus was through the arrival of a neatly wrapped frozen specimen.

  Mount of Phascogale tapoatafa, Brush-tailed Phascogale  Mount of Brush-tailed Phascogale
Image: Benjamin Healley
Source: Copyright Museum Victoria 2003
 

Phascogales are among a rare breed of mammals that practice suicidal reproduction, or semelparity, where one or both sexes die after a single episode of mating. This strategy is seen in some invertebrate and plant species, but is extremely rare in mammals, only occurring in a few marsupials native to Australia, South America and Papua New Guinea. In Australia the male Phascogale, Antechinus, Dasykaluta and Parantechinus are the only mammals where the males literally mate themselves to death.

Mating season for these dasyurid marsupials lasts only a few short weeks, during which promiscuous females and anxious males copulate for hours at a time (Antechinus have been known to go at it for up to 14 hours!). During this concentrated period of breeding the males’ levels of testosterone and stress hormones become so extreme that even their muscles start to break down to help fuel the act. The intensity of prolonged mating causes the males' bodily functions such as their immune system to shut down, exposing their exhausted bodies to infection, internal bleeding and disease shortly after. The males will not even get to see the fruits of their labour, as they all die before their young are born.

Phascogale tapoatafa: Brush-tailed Phascogale Brush-tailed Phascogale from J. Gould's Mammals of Australia, 1863, vol 1, pl 31
Image: Artist: John Gould; Lithographer: H.C. Richter
Source: Out of Copyright
 

So why do you think male phascogales have been programmed to pursue such a life ending labour of love?

The answer lies in their sperm. For phascogales sexual selection occurs after copulating, where the sperm compete inside the female for fertilisation. Rather than fighting to gain access to mate with a female, males need to put all of their energy into fertilising as many females with as much sperm as possible. This also explains the lengthy duration of the mating spree – the more time one male spends mating with a female, the less opportunity other males have at gaining access to her. Combine this with the promiscuous frenzy of their breeding period and many females may nurture offspring from multiple fathers. 

I can only imagine the field day that Isabella would have illuminating the fascinating science behind the phascogale's reproductive biology. A glimpse at any of her online videos will give you an idea.

Links:

Diana O. Fisher, Christopher R. Dickman, Menna E. Jones, and Simon P. Blomberg (2013) Sperm competition drives the evolution of suicidal reproduction in mammals Proceedings of the National Academy of Sciences, published ahead of print 7 October 2013: doi:10.1073/pnas.1310691110

Two eclipses for April

Author
by Tanya
Publish date
11 April 2014
Comments
Comments (1)

Not one, but two eclipses will occur this month and both are partially visible from Melbourne.

Just before sunset on the 15th April, the Moon will rise already totally eclipsed. It should look quite eerie to see a red moon rising above the eastern horizon and it's always amazing how bright the Moon appears as it moves out of the Earth's shadow and returns to its usual splendour. While you are watching the eclipse, be sure to take a look at Mars, which will be just to the left of the Moon and the bright star Spica (in the constellation of Virgo) that will be found just above.

Lunar Eclipse The progression of a total lunar eclipse in August 2007.
Image: Phil Hart
Source: http://www.philhart.com/
 

Two weeks later on the 29th April, the Moon and Sun will come together in the sky and we'll see a partial solar eclipse. The eclipse will begin during the afternoon and reach its maximum point just before sunset. At the height of the eclipse 64% of the Sun's diameter will be covered by the Moon. The Sun will still be partially eclipsed as it sets below the western horizon.

Solar Eclipse The Moon takes a bite out of the Sun.
Image: Phil Hart
Source: http://www.philhart.com/
 

The timings for both the lunar and solar eclipse can be found from the Planetarium's monthly newsletter – Skynotes – which is a great guide for finding your way around the night sky.

Importantly, lunar eclipses are lovely to watch and you don't need any special equipment. Solar eclipses, on the other hand, require a bit of care and planning. Never look directly at the Sun.

There are safe ways to watch a solar eclipse and the easiest is to purchase special eclipse glasses. They are available from the Scienceworks shop and will allow you to watch the event, while protecting your eyesight.

You can also create a simple "pinhole" projection. It's as easy as making a small pinhole in a piece of paper or cardboard. Do not look through the hole, but allow the Sun to shine through and project an image onto a second piece of cardboard. Even a blank wall or a clear patch of ground can make a good surface for projection.

And as I've mentioned previously on the Museum's blog, sometimes nature helps out too. If you can see sunlight travelling through the leaves of a tree, you’ve got yourself some ready-made pinhole projections. Check the ground and it might be covered with little crescent Sun images, just like this great example from the Astronomy magazine website.

About this blog

Updates on what's happening at Melbourne Museum, the Immigration Museum, Scienceworks, the Royal Exhibition Building, and beyond.

Categories