Live Exhibits

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Live Exhibits

The Live Exhibits team look after all the living things on display at Melbourne Museum, from the trees and birds in the Forest Gallery to the thousands of invertebrates in Bugs Alive.

Venom and phobias at SmartBar

Author
by Kate C
Publish date
23 July 2012
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SmartBar is returning to Melbourne Museum by popular demand! On 26 July from 6pm, the second adults-only SmartBar will focus on Mind and The Human Body. The Science and Life exhibitions will be open after dark with talks, displays, activities and music to boot.

The Live Exhibits crew were very popular at the first SmartBar and they are back again with a look at creatures that bite and sting, how venom interacts with the body, and how our minds can turn healthy wariness of venomous animals into debilitating phobias.

Australia is notorious for its venomous wildlife. Even our cute furry Platypus carries a poisoned spur that causes excruciating pain for any unfortunate human on its receiving end. But did you know that venom can have positive effects on humans too? The field of bioprospecting is uncovering new compounds from the venom of snakes, scorpions, centipedes and spiders that may help to treat cancer and many other diseases.

glowing scorpion Scorpions glow when viewed under ultraviolet light due to fluorescent chemicals in the cuticle. The bulb at the end of the tail can inflict a nasty sting.
Image: Patrick Honan
Source: Museum Victoria
 

Arachnophobia – the fear of spiders – is the most common phobia in western society. You might think it's simple evolutionary common sense to fear something that can harm you. However, the lives of the truly arachnophobic are governed entirely by their relationship with spiders, leading some to risk their lives by jumping from moving cars and out of upper storey windows. For others, every daily decision, from the car they drive to where they live, is based on avoiding eight-legged critters.

Huntsman spider on screen door Huntsman spider on your screen door - a welcome friend or nightmarish visitor?
Image: PG Palmer
Source: Image courtesy of PG Palmer, as licensed under CC BY-SA 2.0 Generic.
 

MV's manager of Live Exhibits, Patrick Honan, likes spiders – especially the big black hairy ones. He has helped people face their arachnophobia through cognitive behaviour therapy, followed by a controlled process of desensitisation called exposure therapy. He'll be speaking at SmartBar about the root cause of our fear of spiders, and whether it's justified. Whether you're fond or fearful of spiders, Patrick's stories are not to be missed.

SmartBar's Brain, Mind, Eyes, Drinks and DJ event is on for one night only on 26 July 2012. For more information or to buy tickets online, head over to the SmartBar What's On listing.

Links:

MV Blog: First SmartBar round-up

Bug of the month - Steel Blue Sawfly

Author
by Patrick
Publish date
1 July 2012
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If you're out in the bush or a local park during winter, you're likely to happen across a group of 'spitfires' clinging to the branch of a gum tree in the cold. These insects are technically called sawflies, a group of insects closely related to wasps. There are more than 200 species of sawfly in Australia, but the local species is the Steel Blue Sawfly (Perga dorsalis).

sawfly larvae A small clutch of sawfly larvae clinging to a branch.
Image: Patrick Honan
Source: Museum Victoria
 

The name 'sawfly' derives from a 'sawbench' under the abdomen of the female with which she lays eggs. Female wasps, in contrast, use a pointed ovipositor to lay eggs and in some species this doubles as a sting – adult sawflies do not sting and both adults and larvae are completely harmless.

Patrick Honan Female Steel Blue Sawfly.
Image: Female Steel Blue Sawfly
Source: Museum Victoria
 

Female sawflies use the sawbench to cut the upper surface of a leaf and deposit 60-70 eggs into the leaf tissue. The larvae hatch and feed on gum leaves, grouping together for protection in a rosette pattern, similar to the head-outwards stance adopted by Bison when under attack. This is known as a 'ring defence', or cycloalexy. As the larvae grow, they collect in larger groups around branches during the day and spread out to feed at night.

sawfly eggs A raft of eggs cut into a gum leaf by a female Steel Blue Sawfly.
Image: Patrick Honan
Source: Museum Victoria
 

Like their cousins, the ants, bees and wasps, sawflies show some social behaviour but only in a primitive way. When feeding at night, larvae tap the branch to keep in constant communication with each other. If an individual becomes lost, it will tap more rapidly until it receives an answer from the rest of the group – if an individual becomes completely separated it will not survive long on its own.

Detail of sawfly larva abdomen. Sawflies grouped together on a branch. The pale tips of the abdomen are tapped on the branch to keep in touch.
Image: Patrick Honan
Source: Museum Victoria
 

The activities of a group of sawfly larvae are governed by a few select individuals that become in effect the leaders of the group. They lead the rest out to feed at night and, if they run out of food, lead the group across the ground to other trees. When large numbers of sawfly larvae are present they are able to defoliate small gum trees, but in general are not a major pest.

mass of sawfly larvae A mass of sawflies resting during the day, the result of the merging of several smaller groups.
Image: Patrick Honan
Source: Museum Victoria
 

When ready to pupate, the larvae leave the host tree and burrow down to make mass cocoons in the soil. Here they sit through spring and summer to emerge in early autumn. Adults have no mouthparts and do not feed, living only for a week or so.

pupating sawfly larvae Sawfly larvae in their pupal cells underground, preparing to pupate.
Image: Patrick Honan
Source: Museum Victoria
 

Not all emerge, however, as many succumb to parasitic flies. These flies, about the size of a blowfly, will lay eggs in the sawfly larvae and the fly maggot literally eats its host from the inside out, eventually emerging from the sawfly's cocoon.

parasitised sawfly larva An opened pupal cell showing the consumed sawfly larva on the left, and the engorged parasitic fly larva on the right.
Image: Patrick Honan
Source: Museum Victoria
 

Sawfly larvae have an unusual defensive mechanism that has given them the name 'spitfires'. They store eucalyptus oil in a small sac in their gut, and regurgitate this oil when under threat. Despite their nickname, they are unable to actually spit this fluid and the oil itself is harmless unless eaten (like all eucalyptus oil). In fact it has a very pleasant eucalytpusy smell.

sawfly larva mouthparts A large blob of frothy regurgitate in the mouthparts of a sawfly larva.
Image: Patrick Honan
Source: Museum Victoria
 

Australia is one of the main strongholds of Symphyta, the suborder of insects to which sawflies belong. The Steel Blue Sawfly is one of the few insect species active in Victoria during winter, so next time you're in the bush take the time to stop and smell the sawflies.

Bug of the Month - the earthworm

Author
by Tim Blackburn
Publish date
1 June 2012
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June's Bug of the Month is certainly not a bug, but the integral role that the earthworm plays in many terrestrial ecosystems is why I've selected it this month. The famously influential Charles Darwin studied earthworms at great length. His 1881 book, The Formation of Vegetable Mould Through the Action of Worms, With Observations on Their Habits, sold more copies than On the Origin of Species. Darwin commented, "...it may be doubted if there are any other animals which have played such an important part in the history of the world as these lowly organized creatures."

Earthworms belong to the phylum Annelida which incorporates all the segmented worms, including the marine worms and the leeches. More than 3,000 species of earthworm, ranging in length from one centimetre to two metres, are found right across the planet in a diversity of habitats – including Melbourne Museum's gardens.

Earthworm An earthworm, showing its long segmented body.
Image: Tim Blackburn
Source: Museum Victoria

Earthworms inhabit moist, rich soils and emerge at night to feed on decomposing organic matter. They possess bristle-like hairs called setae which form a ring around most body segments. The setae help the worm to sense its environment and to grip the soil as the earthworm moves around. They do not have a skeleton, per se, but possess a fluid-filled body cavity (a coelom) against which their muscles contract. A swollen band towards their anterior (front) end, called a clitellum, secretes an egg-filled cocoon soon after mating.

Earthworm The bulge visible toward the anterior end of this earthworm is the result of the peristaltic (wave-like) contraction of its muscles against its hydrostatic skeleton. The swollen, orange band around the body is the clitellum.
Image: Tim Blackburn
Source: Museum Victoria
 

earthworm clitellum A close-up of the earthworm's clitellum
Image: Tim Blackburn
Source: Museum Victoria
 

Earthworms play an important role in stabilising soil structure and maintaining soil fertility. They are instrumental in the decomposition of organic matter and the associated replenishment of soil nutrients. Charles Darwin estimated that earthworms add a 5mm layer of nutrient-rich soil to English pastures each year.

Earthworms have a lower optimal body temperature than most invertebrates and prefer damp soils, since they must keep their cuticle moist to be able to respire through it. Earthworm activity will be high in Melbourne during June as temperatures plummet and evaporation decreases. I found a dense population of earthworms while digging up one of the garden beds in the Milarri Garden this week. The worms seem to be breaking down much of the leaf litter that accumulated during autumn, thereby returning nutrients to the soil.

Trees in autumn The current view of Carlton Gardens, looking out from the Millari Garden. Earthworms and soil microorganisms will break down the autumn leaves within a matter of months.
Image: Tim Blackburn
Source: Museum Victoria
 

The benefits that earthworms provide for soil are due to their burrowing habits and their methods of feeding, digestion and excretion. They swallow much of the soil and organic matter they encounter and deposit it as nutrient-rich faecal casts. The waste products and mucus secretions of the worms provide nutrients for many microorganisms, which improve soil fertility through further decomposition. Earthworms' burrowing actions also aerate and drain the soil, preventing it from becoming compacted and waterlogged.

These animals are essential components of both natural and human-dominated ecologies, and they've also influenced human history. For example, the migration and settlements of early humans were limited by the productivity and fertility of soils. The role that earthworms have played in the burial of ancient buildings over millennia was studied at length by Charles Darwin, a phenomenon which illustrates just how closely human societies are intertwined with earthworms. The world's diverse ecologies, agricultural systems and expansive cities owe much to the largely unnoticed action of earthworms below ground.

Links

Infosheet: Giant Gippsland Earthworm

Via Darwin Online: The Formation of Vegetable Mould Through the Action of Worms, With Observations on Their Habits

Hairy but not so scary

Author
by Chloe
Publish date
2 May 2012
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Chloe is a keeper with Live Exhibits at Melbourne Museum.

Who knew that within Melbourne Museum there are two rooms not considered to be in Australia?

Every year Australian Quarantine and Inspection Service (AQIS) officers confiscate thousands of objects being brought illegally into the country through the post, airports and seaports. These items include food, drugs, plants and even live animals.

King Baboon tarantula (<em>Citharischius crawshayi</em>) King Baboon tarantula (Citharischius crawshayi)
Image: Alan Henderson
Source: Museum Victoria
 

Such illegal items can pose a significant risk to Australian wildlife. Tarantulas are a long-lived spider which can produce thousands of eggs each year. If they were to become established in the wild exotic tarantulas would have the ability to decimate populations of small native animals.

In 1996 a population of Mexican Redrump tarantulas (Brachypelma vagans) was discovered in a citrus field in Florida, America. The population is believed to have stemmed from one gravid (carrying eggs) female who was released after she was no longer wanted as a pet. Over 100 individuals were found in a single survey of the 40 acre property. The Mexican Redrump tarantula is not native to Florida but has been imported for the pet trade since the 1970s. It is thought that this incidence of releasing an exotic pet has alone caused devastating effects on local fauna. With Australia's warm climate it would be easy to find ourselves in a similar situation to Florida if we didn't enforce strict quarantine measures.

Mexican Redrump tarantula (<em>Brachypelma vegans</em>) Mexican Redrump tarantula (Brachypelma vegans)
Image: Alan Henderson
Source: Museum Victoria
 

Tarantulas with their unique markings, behaviours, and basic husbandry are popular pets in Europe and America. Many species are illegally transported around the world with collectors willing to pay hundreds of dollars for specimens. In Australia there are numerous species of native tarantulas that can be kept legally as pets.

Venezuelan Sun Tiger tarantula (<em>Psalmopoeus irminia</em>) Venezuelan Sun Tiger tarantula (Psalmopoeus irminia)
Image: Alan Henderson
Source: Museum Victoria
 

Queensland whistling tarantula (<em>Selenocosmia crassipes</em>) Queensland whistling tarantula (Selenocosmia crassipes)
Image: Alan Henderson
Source: Museum Victoria
  

But what happens to the items AQIS confiscate? Many items are destroyed to protect Australia's precious ecosystem. However, some lucky spiders are spared. They get used by museums and zoos to act as educational aids.

Quarantine room enclosures off display at Melbourne Museum Quarantine room enclosures off display at Melbourne Museum
Image: Chloe Miller
Source: Museum Victoria
 

Melbourne Museum is home two quarantine rooms where we house 14 tarantulas that were confiscated by AQIS. These spiders are housed under strict conditions which meet AQIS standards. These standards include the treatment of objects leaving the rooms such as waste, water, uneaten food and other implements. These items must be double bagged, recorded and frozen at minus 20 degrees for six weeks. The quarantine room is not considered to be in Australia territory but a grey zone within Australia.

Bugs Alive! Quarantine room at Melbourne Museum Bugs Alive! Quarantine room at Melbourne Museum
Image: Chloe Miller
Source: Museum Victoria
 

One quarantine room at the museum is located within the Bugs Alive! gallery and allows visitors to see its inner workings through a glass viewing wall, while the other room is located behind the scenes.

Our display spiders are fed every fortnight on Saturdays. One of our 'behind the scenes' spiders is fed weekly on Fridays at 3pm live on the web.

Tarantula feeding live on the internet Tarantula feeding live on the internet
Image: Chloe Miller
Source: Museum Victoria
 

Currently on display via the webcam is a Brazilian Salmon Pink tarantula (Lasiodora parahybana). Brazilian Salmon Pinks are the third largest species of tarantula with a leg span reaching 25cm.

Brazilian Salmon Pink tarantula (<em>Lasiodora parahybana</em>) Brazilian Salmon Pink tarantula (Lasiodora parahybana)
Image: Alan Henderson
Source: Museum Victoria
 

Equipped with urticating (stinging) hairs to flick at predators, she only uses her fangs as a last resort. This girl is a keen feeder, often climbing up the keeper's forceps to get to its prey.

References:

Brazilian Salmon Pink fact sheet from WAZA

Brazilian Salmon Pink Birdeater from Australian Reptile Park

Mexican Redrump Tarantula fact sheet [PDF 179KB] from the University of Florida

1996 Florida Mexican redrump tarantula incident

Southern Grasstree

Author
by Brendan
Publish date
1 April 2012
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Exhibition horticulturalist Brendan Fleming is turning April's Bug of the Month post into Plant of the Month. He is one of the Live Exhibits staff that tend the plants in the Forest Gallery and Milarri Garden.

From an early age I have enjoyed bushwalking within the Grampian Ranges in western Victoria. One particular plant species found there that fascinates me is Xanthorrhoea australis, the Southern Grasstree. X. australis is the most widespread of the genus of 30 odd species and subspecies. It is found down the eastern coast of Australia.

Southern Grasstrees A spectacular display of Southern Grasstrees following a bushfire in the Grampians.
Image: Brendan Fleming
Source: Brendan Fleming
 

Its appearance is unlike any other indigenous plant. Older grasstrees have a blackened, sometimes gnarled elevated trunk, with bluish-green whorled leaves that seem to explode from the crown and drape down to skirt the stem.

The Southern Grasstree is very slow-growing. It grows approximately one to three centimetres per year, reaching a height of three metres in about 100 years. It has a shallow root system and is found in even the poorest of soils. Whilst not generally occurring in areas with less than 250mm rainfall, it does best in areas exceeding 500mm per year. Southern Grasstrees are found in the understorey of woodlands, heaths, swamps, and rocky hillsides.

Grasstree species are mostly distinguished by the shape of their leaves in cross-section. X.australis has a diamond shape, and with the leaves being softer than other species.

apex of a Southern Grasstree Close up of the apex of a Southern Grasstree in Milarri, showing a single diamond-shaped leaf in cross section.
Image: Brendan Fleming
Source: Museum Victoria

From germination it takes about seven years to reach maturity, and although sporadic flowering and fruiting can occur thereafter, X.australis generally flower following fire. It is not well understood why fire stimulates reproduction, but cutting off the leaves can also initiate flowering. Application of ethylene, which is present in smoke, has a similar effect, indicating that flowering is stimulated from a hormonal response to leaf removal.

I found an extraordinary scene following bushfires several years ago in the Grampians National Park. Thousands of flower spikes up to 3m high as far as the eye can see, even curly ones, evoking some Leunig illustration!

Grasstree flower spikes Although most flower spikes are perfectly vertical, I occasionally see odd shapes at the Grampians.
Image: Brendan Fleming
Source: Brendan Fleming

The flowers are highly scented and produce much nectar, prized by birds, mammals and insects which pollinate the flowers. Each stalk can produce up to 10,000 seeds.

Southern Grasstree flower spike Close-up of the Southern Grasstree flower spike showing individual flowers.
Image: Brendan Fleming
Source: Brendan Fleming
 

Southern Grasstrees are quite susceptible to Phytopthora cinnamomi (root rot), often being the first plants to show symptoms. Hence they are a good indicator of the presence of the disease.

Drenching Southern Grasstree roots with Phosphonate Drenching with Phosphonate is a good way to boost the Southern Grasstree's defences against the Cinnamon Fungus Phytopthora.
Image: Chloe Miller
Source: Museum Victoria

Xanthorrhoea australis is not difficult to propagate. Seed germinate readily in just a few weeks, with no pre-sowing treatment required. Just be patient though - growth is very slow. A grasstree I germinated from seed was well-established but still trunkless after 10 years, and made a handsome addition to my garden.

Grasstrees feature heavily in Indigenous culture. Uses include weapons and fire sticks from flower stalks, sweet drinks from flower nectar, and edible leaf bases.

I don't have to go to the Grampians to enjoy grasstrees. The Milarri Garden at Melbourne Museum displays these remarkable plants right in the heart of Melbourne. Exit the Forest gallery to the North terrace and meet Milarri from its western end. It really is a dramatic entrance to the Museum's Indigenous garden.

Grasstrees at the entrance to Milarri Walk Grasstrees at the entrance to Milarri Walk from the North Terrace during autumn.
Image: Brendan Fleming
Source: Museum Victoria
 

References:

Flora of Tasmania

Wrigley, J. & Fagg, M., 1983, Australian Native Plants, William Collins, Sydney, 512pp.

Bugs for Brunch

Author
by Adrienne Leith
Publish date
28 March 2012
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Adrienne creates and presents public programs at Melbourne Museum.

What do you eat when you are having bugs for brunch?

Well, scorpions for starters, followed by BBQ-flavoured mealworms. Or perhaps you prefer your mealworms simply roasted with a dipping sauce? And would you like crunchy crickets with that?

A plate of roasted mealworms and crickets. A plate of roasted mealworms and crickets.
Image: Tom Pietkiewicz
Source: Umkafoto
 

More than 3,000 ethnic groups in 113 countries eat insects and other invertebrates, and in many places they are preferred over beef, pork and lamb. Producing insects generates fewer greenhouse emissions than for other forms of meat production and you get more for the same effort: less feed produces more protein. This means a high-protein and low-fat food source that leaves a smaller environmental footprint. While eating insects makes environmental sense, it's pretty confronting to many of us.

Developed as a children's program for the Melbourne Food and Wine Festival, the Bugs for Brunch events ran over four days and tickets sold out fast. Surprisingly, there were just as many young adults as children (with their parents) who came along learn about – and taste - edible bugs. They wanted to do something different, something fun, something with their friends and family. But were they ready to eat bugs?

Most declared they were slightly squeamish and only a few had ever eaten a bug. After being shown how many bugs are already in our food, they were even more grossed out.

But with tastes of bug vomit (delicious honeycomb from Mount Dandenong) to sweeten them up, and up close and personal viewings of all kinds of edible bugs from Bogong Moths and bardy grubs to scorpions, grasshoppers and Chilean Rose tarantulas (Grammostola rosea), people's opinions shifted.

Woman holding beetle grub A bardy grub (beetle larva) at Bugs for Brunch.
Image: Tom Pietkiewicz
Source: Umkafoto
 

After seeing lots of images of people eating bugs, looking through bug recipe books and watching a Pad Thai being made with mealworms, they were ready to eat! Lollypops with bugs in them and mealworm chocolate chip cookies gave them a soft approach to the "whole bug in mouth" experience. But by the end, those roasted toasted whole bug snacks were being scoffed. They couldn't get enough and every plate was empty by the end.

Pad Thai with mealworms. Pad Thai with mealworms.
Image: Tom Pietkiewicz
Source: Umkafoto
 

The Bugs for Brunch program was developed and delivered by Patrick Honan and Rowena Flynn from the museum's Live Exhibits team and Adrienne Leith from Education and Community Programs. The insects at the Bugs for Brunch event came from one of the country's few consumable insect producers and were bred under hygienic conditions that comply with Australian Food Standards.

Links:

Edible Forest Insects, Food and Agriculture Organization of the United Nations

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

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