Kate C

DISPLAYING POSTS BY: Kate C (172)

Kate C

Kate is MV's online writer and editor. Her job is to dig up great stuff to put on the museum's website. Kate loves shiny things, cake and creepy crawlies.

Alpine frogs and chytrid fungus

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by Kate C
Publish date
17 January 2014
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Frogs were an important focus for the Alps Bioscan survey in Victoria's Alpine National Park in November last year. The deadly amphibian chytrid fungus, Batrachochytrium dendrobatidis, thrives in cool environments, meaning high-altitude frog populations are particularly susceptible.

Dr Katie Smith, Collection Manager of Vertebrates, led the frog-hunting team at the Alps and explained why this fungus is so insidious. "It's a major contributor to global amphibian decline. Lots of frogs worldwide are affected," she said. "It penetrates their skin and leads to death in some species and individuals, while some are able to survive it and act as carriers."

View this video with a transcript

The museum's frog team searched for frogs in several sites in the Alps and collected skin swabs from every frog found. The swabs will be tested for the presence of chytrid (pronounced 'kit-trid') as part of ongoing monitoring by researchers from the Arthur Rylah Institute for Environmental Research. "We need to know what populations have it and whether this leads to changes in those populations, such as whether there's lower species diversity in areas where chytrid fungus is present."

The chytrid fungus has a free-living stage called a zoospore and a reproductive stage called a zoosporangium. Zoospores can live several weeks in the water until they find a host frog to infect. Once settled, the zoosporangia cause the frog's skin to thicken and slough away. There are a few hypotheses as to how the chytrid fungus kills frogs. One hypothesis proposes that a frog with a heavy chytrid infestation can't maintain its salt balance. Sodium and potassium levels, essential for normal muscle and nerve function, drop significantly and the frog dies from cardiac arrest.

froglet A froglet found during the Alps Bioscan. Froglet species seem to have some resistance to chytrid fungus, and may act as carriers between water bodies.
Image: David Paul
Source: Museum Victoria
 

Researchers believe that the fungus arrived in Australia in the 1970s, and is linked to the sudden decline (and in some cases, extinction,) of several local species, including the Southern Gastric Brooding Frog and the Southern Corroborree Frog. There are a few theories about how it got here, but the most likely culprit is the international trade in African Clawed Frogs for use in pregnancy tests. In the 1930s it was discovered that injecting one of these frogs with the urine of a pregnant woman caused the animal to produce eggs. Hundreds of thousands of frogs were brought into Australia from Africa for this purpose and probably, with them, the chytrid fungus. While the fungus was first identified in 1998, retrospective examination of historical specimens found the earliest known chytrid infestation on an animal collected in 1938. This African Clawed Frog specimen, held by the South African Museum, supports the theory of African origin.

Once loose in a new environment, chytrid fungus can spread rapidly. "It can be spread by frogs – anything that moves through those water bodies, even other animals that visit those areas and researchers themselves," explained Katie. "You might walk into one site, jump in the car and accidentally transfer it to a healthy population."

You can help prevent the spread of chytrid fungus in a couple of ways. Firstly, says Katie, "never move a frog, tadpoles or eggs that you find in one area to another area, because you don't know which populations may have the chytrid fungus." Frogs are protected in Australia which means that you cannot legally catch, remove or relocate them; the threat of chytrid fungus is another good reason to leave them where they are. Frogs often hitchhike from Queensland in bunches of bananas, so if you find a stowaway in your supermarket, follow the instructions of the Victorian Frog Group and never release the frog into the wild.

Katie continued, "secondly, if you're moving between water bodies, wash your shoes really well and anything else you put in water." The Alps Bioscan teams bleached and scrubbed shoes and equipment between each aquatic field site, and Katie's frog team wore fresh surgical gloves when handling each frog.

The results from the survey and chytrid tests will be available later this year once the researchers have completed their analysis.

Links:

Ché Weldon, Louis H. du Preez, Alex D. Hyatt, Reinhold Muller,and Rick Speare. Origin of the Amphibian Chytrid FungusEmerg Infect Dis. 2004 December; 10(12): 2100–2105.

David Hunter, Rod Pietsch, Nick Clemann, Michael Scroggie, Gregory Hollis and Gerry Marantelli. Prevalence of the Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis) in Populations of Two Frog Species in the Australian Alps. 

Summer visitors build LEGO mosaics

Author
by Kate C
Publish date
3 January 2014
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This January we have The Brickman in residence at Melbourne Museum! Ryan McNaught is LEGO® Certified Professional - and yes, that means his job is to play with LEGO®.

Ryan created two mystery mosaics for our visitors to construct over the summer holidays. Thousands of coloured plastic bricks, plus the support rig that holds the mosaics, arrived just before Christmas and the fun began on Boxing Day.

Men unloading from truck. Ryan's crew unloading the pieces of the framework designed to support the mystery mosaics.
Image: Rod Start
Source: Museum Victoria
 

Man assembling frame Assembling the mosaic frames. And what do you use to hold LEGO® baseplates together while you bolt them down? Bits of LEGO®, of course!
Image: Rod Start
Source: Museum Victoria
 

Men with LEGO® Ryan unpacking hundreds of little numbered square plates, which form the mosaic when covered in LEGO® pieces.
Image: Rod Start
Source: Museum Victoria
 

Bits of lego Each of the plates are numbered, colour-coded, and correspond to a space on the mosaic frame.
Image: Rod Start
Source: Museum Victoria
 

visitors doing lego activity in foyer Visitors began constructing the mystery mosaic in the Melbourne Museum foyer on Boxing Day.
Image: Rod Start
Source: Museum Victoria
 

You can come and help fill in the mosaic between 11:00 and 3:00 every day until 26 January as part of the Summer holiday program at Melbourne Museum.

Great White Sharks at IMAX

Author
by Kate C
Publish date
2 January 2014
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William Winram is a champion freediver and a passionate advocate for the protection of marine ecosystems. He uses his freediving abilities to help monitor shark populations, and he visited Melbourne Museum recently to talk about Great White Shark 3D, a new IMAX film that features him doing exactly that.

William Winram William Winram
Image: Michele Monico
Source: William Winram
 

Most divers use SCUBA breathing apparatus, but freedivers like William reach similar depths while holding their breath. This is a very different way to interact with sharks, as William explains. "When you hold your breath, your heart rate reflexively slows. There's a whole shift, physiologically, that doesn't happen in SCUBA diving." He believes that freediving makes him less intrusive, because "with SCUBA, you're entering as an alien. You're taking apparatus from the surface world, so right away your relationship is totally different." Freedivers can also move more freely in the water column, and don't generate noisy bubbles. "For a lot of species, bubbles are a sign of aggression," says William.  "If a male sea lion is getting upset, he blows bubbles and barks at us. That's how he shows his dissatisfaction."

William Winram preparing William Winram preparing for his world record freedive attempt in September 2013, Egypt.
Image: Alice C. Attaneo
Source: William Winram
 

William describes the sharks he encounters – Great White Sharks, Hammerheads, Tiger Sharks and others – as "shy, curious and cautious predators", quite unlike the killing machines of media and cinema. "Sharks are not obsessed with or addicted to killing, but they do need to eat. They know that we're not their normal diet, so they don't typically eat us." His calm, respectful approach to the world's largest predatory fishes means he is able to tag sharks harmlessly, unlike some other tagging techniques that often kill the animal.

"It's like you're walking down the hallway and I hit you in the rear end with a hypodermic needle. Afterwards you have a little bruise but you're fine." He and his colleagues aim for the thick muscle at the base of the shark's dorsal fin and use a specially modified spearfishing gun. All that's left is a small dart and tag – and these tags are allowing scientists to learn about the feeding behaviour and global movement of sharks. Tagging has also shown that Great White Sharks head for a mysterious area in the middle of the Pacific known as the Shark Café. No one is quite sure what the sharks do there, but it is clear that the animals have complex annual migratory patterns.

He sees Great White 3D as an opportunity to address the misunderstandings about sharks and encourage interest in their conservation. "We like to demonise sharks and we like to glorify other creatures, and all of it is false. People want to have this fantasy, an unreal world where things are either beautiful or ugly, nice or not. Sharks are easy to exploit because they're not cute and cuddly," he says. 

William Winram freediving William Winram freediving with a Great White Shark in Isla Guadalupe, Mexico.
Source: Still from Great White Shark 3D
 

Like all apex predators, Great White Sharks are found in relatively low numbers, yet they are vital in moderating populations of other species. Ecosystems suffer when they lose their apex predators, so the decline in sharks from human activities worries William very much. "We need to understand that we are part of an ecosystem. 50 per cent of the oxygen that we breathe comes from the sea.  At a certain point, if you kill them all off, the sea is done. It's time to respect your position and your role in your ecosystem."

Great White Shark 3D is now playing at IMAX Melbourne Museum.

Links: 

William Winram's website

ABC Science: Great whites hang out in 'shark cafe'

'In deep water' by Tim Winton for the Sydney Morning Herald

Burrowing bees

Author
by Kate C
Publish date
18 December 2013
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No biologist worth their salt will stumble across a burrow in the ground without having a good stickybeak. And museum biologists are definitely worth their salt*.

So when the Alpine National Park Bioscan team found several hundred small burrows in one spot, they couldn't just wonder if they were made by crayfish or perhaps mole crickets. This hypothesis needed testing. Colin from Live Exhibits got to digging.

hut in the Alps Burrows in the foreground and Davies Plain Hut in the background.
Source: Museum Victoria
 

He stuck a blade of grass down the burrow and used a spoon to carefully dig around it. About 30 or 40 cm down he found, not a cray or cricket, but a little bee. It was no coincidence; a second excavation turned up another bee in the next burrow.

Colin digging holes Colin digging up burrows with a spoon.
Source: Museum Victoria
 

The bees belong to the subfamily Halictinae, which happens to be the speciality of museum entomologist and bioscan participant Dr Ken Walker. He collects most of his study specimens as they are out foraging and rarely sees the burrows. And he'd never seen burrows in such high density –about 400 in one small grassy area.

Ken explained that the bees belonging to the genus Lasioglossum and subgenus Parasphecodes. "Lasioglossum is one of the largest genera in Australia, doing most of the work of pollinating." These burrows are where the female bees brood the next generation.

Halictine bee The halictine bee responsible for the burrows.
Image: David Paul
Source: Museum Victoria
 

"They're a semi-social bee," said Ken. "In a single nest there can be six to ten females, which are all queens. They all lay their own eggs, and they all help excavate that main tunnel but each one of them then makes a lateral tunnel by themselves. At the end they build a group of cells each lined with saliva, and they put in a pollen ball mixed with a little bit of nectar, and they lay an egg and close the whole thing up."

But that's not the end of the story, because the bee larva isn't alone in the cell. Looking closely, Ken spotted a number of large mites on the backs of the bees. The mites are harmless to the bee since they're a non-feeding, migratory (or hypopial) life stage, waiting patiently for the bee to finish stocking the brood cell with pollen.

Halictine bee with mite The red arrow shows the location of a hitch-hiking mite on this bee.
Image: Ken Walker
Source: Museum Victoria

Mite on a bee Detail of a mite on the back of a bee.
Image: Ken Walker
Source: Museum Victoria
 

Said Ken, "just before the bee closes up the cell, she turns around and brushes one or two mites off, which then develop to the feeding and sexual stages." The mites act like little housekeepers, eating any mould or fungus that attacks the pollen ball and thus keeping it fresh for the developing bee. When the new adult bee is ready to emerge, the mites' own young clamber aboard and travel on to the next burrow. "It's a wonderful relationship there."

Halictine bee Dorsal view of the burrowing semi-social bee.
Image: David Paul
Source: Museum Victoria
 

So there you have it – nosy biologists reveal an underground community of fascinating little animals, and Parks Victoria rangers have an interesting reason to recommend that tents be pitched away from the field of muddy burrows.

*Humans contain about 0.4% salt by weight. So a 70kg museum biologist, say, contains about 280g salt**. That much table salt costs about a dollar from a supermarket. If instead we say they're worth their weight in gold, according to today's price, and the Dynamic Earth scale, that puts our 70kg biologist at $3,112,900. The real value is probably somewhere in the middle.

**Except marine biologists. They're a bit saltier.

Links:

ABC Bush Telegraph: Hive of activity reveals all in alpine bioscan

The Age: Critter census reaps bonanza for researchers

MV Blog: Alpine Bioscan

Martin Sharp's Federation Tapestry

Author
by Kate C
Publish date
4 December 2013
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We're sorry to hear of the recent death of Sydney artist Martin Sharp, His many achievements – among them the co-creation of Oz magazine in the late 1960s and the psychedelic refurbishment of Sydney's Luna Park in the 1970s – Sharp designed the tenth and final panel of the Federation Tapestry which hangs in Melbourne Museum.

Celebrations 2001 Federation Tapestry Celebrations 2001, the tenth of the Federation Tapestry series, designed by Martin Sharp.
Source: Museum Victoria
 

Central to Sharp's tapestry, titled Celebrations 2001, is one of his most often-used motifs: the word 'Eternity' in elegant copperplate script. This is a tribute to Arthur Stace who wrote the word on the streets of Sydney, anonymously, for decades. Sharp surrounded this centrepiece with other powerful images of Australia: 'Sorry' written in the sky above the Sydney Opera House, an artwork by Ginger Riley, a quote from Patrick White, and the First Fleet.

Links:

Tribute to Martin Sharp by Sean O'Brien on ABC Open

Infosheets about the Federation Tapestry

Flags for Melbourne

Author
by Kate C
Publish date
25 November 2013
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Two new flags are flying above the Royal Exhibition Building for On Top of the World: Flags for Melbourne. This public art project takes the NGV’s new exhibition, Melbourne Now, outside the gallery and to flagpoles across the City of Melbourne.

Melbourne Now flag John Warwicker's Melbourne Now flag flying above the Royal Exhibition Building.
Source: Museum Victoria
 

The first of the flags was unfurled at Princes Hill on Tuesday in tribute to Ivor Evans, a Princes Hill student who was one of the five winners of a public competition to design the current Australian flag in 1901. This design was first flown at the Exhibition Building, which was the seat of the federal parliament at the time. On 3 September this year, the Royal Exhibition Building celebrated the 112th anniversary of flying the Australian flag, while the Aboriginal and Torres Straight Islander flags have been permanent fixtures since restoration of the flagpoles at either end of the building in August this year.

Each of the art project's sixteen flags were designed by local artists; those flying from the Royal Exhibition Building are by designer John Warwicker. In his artist’s statement, Mr Warwicker explains his design as an acknowledgement of the connection of Aboriginal people to the land, with the sun shared between the traditional owners of Australia and the immigrants who settled here, guided by the Southern Cross. Mr Warwicker sought permission from Harold Thomas to adapt his iconic Aboriginal flag design, and Mr Thomas is expected to visit for a viewing early in the new year.

John Warwicker's Melbourne Now flags John Warwicker's Melbourne Now flags flying above the Royal Exhibition Building, with the Australian Flag up above.
Source: Museum Victoria
 

The flags will be in place until the Melbourne Now exhibition ends on 23 March 2014.

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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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