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Melbourne Museum

Melbourne Museum explores life in Victoria, from our natural environment to our culture and history. Located in Carlton Gardens, the building houses a permanent collection in eight galleries, including one just for children.

The New Holland mouse

Author
by Phoebe Burns
Publish date
31 July 2015
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The New Holland mouse (Pseudomys novaehollandiae) is one of Victoria’s threatened native rodents. The charismatic little species has only been recorded in three areas across the state in the past 15 years (the blue dots in the map below), whereas historically it was recorded in ten, including metropolitan Melbourne (the red dots in the map below). That’s why I embarked upon a PhD to determine the status of NHMs across Victoria and help protect this species from further decline.

New Holland mouse detection sites New Holland mouse detection sites across Victoria. Red dots indicate sites in areas where the species has not been detected in at least 15 years, blue dots indicate areas with more recent detections. Dates show the range of years during which New Holland mice were known at each site.

One of the greatest challenges for studying the status and conservation of New Holland mice (and many native Australian rodents) is that they can be very difficult to find; you can’t just see them with your binoculars or hear them calling in the bush. Many native rodents, including NHMs, go through natural periods where they persist in such low numbers that traditional survey efforts fail to detect them. New Holland mice are also particularly fickle about their habitat preferences and may only persist locally for a few years before moving on, making their populations even more difficult to track.

New Holland mouse captured and released New Holland mouse captured and released using live trapping.
Image: Phoebe Burns

That’s why I’ve been trialling the use of cameras to detect the New Holland mouse. Traditional live trapping can be a great method for detecting a species in an area, and it’s critical if I want to know about health and reproduction, estimate abundance, or get DNA samples. However, sometimes when a species is at low densities, it takes a huge amount of effort to be reasonably confident that the species isn’t there, which in a world of limited time and funding drastically reduces the area you can survey. This is a real challenge when your species moves in the landscape.

This is where cameras can come in handy – you set them once and, rather than having to come back every morning and afternoon to check each trap, you can just leave them in place for weeks at a time. The animals are attracted to a tasty lure (I like to use peanut butter, oats, golden syrup and vanilla essence), and while they investigate, the camera senses the heat and motion and snaps a photo.

New Holland mouse Camera trap image of a New Holland mouse clinging to a bait station.
Image: Phoebe Burns

Cameras allow you to survey much wider areas, for longer periods of time with a fraction of the effort of live trapping – at least until you have to sift through all the images and identify the animals. Once I know that NHMs are present in an area from the camera trapping, I can target those areas for live trapping to collect the rest of my data. My challenge, and the reason I did a camera trial, rather than just jumping straight into using cameras as a survey method, was identifying New Holland mice in the images.

New Holland mouse and house mouse Camera trap image of a New Holland mouse climbing on a bait station with a house mouse standing up against the base.
Image: Phoebe Burns

Rodents tend to look very similar on camera, particularly if the images are in black and white. It doesn’t help that New Holland mice are about the same size as the non-native house mice (Mus musculus); they can be hard for some people to tell apart when they are holding them in their hand. Since the house mouse has infiltrated all known New Holland mouse habitat in Victoria, I needed to tell them apart from less than perfect images in colour and in black and white.

New Holland mice and house mice Infrared camera trap images of New Holland mice (left) and house mice (right) investigating bait stations.
Image: Phoebe Burns
 

Tens of thousands of images later, I can happily say that New Holland mice and house mice are distinguishable from one another in both colour and black and white images. In the colour images the species can be distinguished by differences in colouration, but in black and white the distinction is all in the shape of the two rodents. New Holland mice have a much sturdier build, a thickset neck and a snubby nose, whereas house mice are much more slender, with a pointed nose. It's not unlike the difference between rugby and footy players.

Now that I’ve got the IDs sorted, I’ll be using cameras (and live traps) to survey across Victoria and see where the New Holland mouse is persisting, so that we can do our best to halt the species’ further decline.

You can follow my PhD progress and fieldwork on Twitter and at my website to stay up to date with the status of New Holland mice as I search for them throughout Victoria.

Additionally, you can try your hand at identifying New Holland mice in my New Holland mouse quiz.

Welcome to the family, Pluto

Author
by Tanya Hill
Publish date
16 July 2015
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image of planets Welcome to the family. Ben Gross/twitter, CC BY-SA

What an amazing time for space exploration. The picture of the solar system from my childhood is now complete, as seen in this great family portrait produced by Ben Gross, a research fellow at the Chemical Heritage Foundation, and distributed via twitter.

I love this image because it shows each world in close-up, using some of the latest pictures from space exploration. As we celebrate seeing Pluto for the first time, it’s remarkable to think that this completes a 50 year task.

It has been NASA that has provided the first close-up views of all these worlds. Here’s the rundown:

  • Mercury: Mariner 10 (1973)
  • Venus: Mariner 2 (1962)
  • Mars: Mariner 4 (1965)
  • Jupiter: Pioneer 10 (1973)
  • Saturn: Pioneer 11 (1979)
  • Uranus: Voyager 2 (1985)
  • Neptune: Voyager 2 (1989) and
  • Pluto: New Horizons (2015)

But science never stays still. When New Horizons left Earth in January 2006, Pluto was a planet. Later that year an important reassessment was made of the Solar System and Pluto became the first of the dwarf planets.

The ‘Not-Planets’

The Planetary Society’s Senior Editor, Emily Lakdawalla, has teamed together the ‘Not-Planets’. These are the close-up views, shown to scale, that have been captured of the largest moons, asteroids and dwarf planets.

image of non-planets in the solar system Montage by Emily Lakdawalla. The Moon: Gari Arrillaga. Other data: NASA/JPL/JHUAPL/SwRI/UCLA/MPS/IDA. Processing by Ted Stryk, Gordan Ugarkovic, Emily Lakdawalla, and Jason Perry.

It clearly shows that there are many diverse and interesting worlds to explore beyond the eight planets of our solar system.

New Horizons is the first spacecraft to start exploring the Kuiper Belt, an icy realm of objects orbiting 5 billion kilometres or more beyond the sun. It’s the chance to observe a dwarf planet, something distinct from the terrestrial planets and the gas giants.

It was in 1992 that astronomers discovered Pluto was not alone. The first Kuiper Belt Object, designated 1992 QB1, is a 100-kilometre sized object that orbits well beyond Pluto.

Now more than 1,000 objects have been detected in this realm, and the belt likely contains many more. Most are small compared to Pluto, but there are some stand-outs such as Quaoar, and the dwarf planets Eris, Makemake and Haumea.

Don’t forget to phone home

The suspense of the mission has certainly been high. To maximise the amount of data that New Horizons could collect, the spacecraft did not communicate with Earth for the duration of the flyby. As described by Mission Operations Manager Alice Bowman, it was the moment when you let your child free.

The team had prepared New Horizons, told it what work needed to be done and in that radio silence they had to trust that all would go to plan.

Just before 11am today (AEST), New Horizons checked in – showing it to be the perfect child to the relief of its many anxious “parents”. It was only a brief phone home, but in that short time the scientists confirmed that all telemetry was spot-on, the spacecraft followed the path that had been set for it and there were no error messages recorded on any of the systems.

No data was transferred in that brief connection, but it was established that the main computer system, which records all the data collected by the spacecraft, showed the expected number of segments had been used. In other words, data had been collected.

We will soon see Pluto and Charon in even higher resolution. Their geology will be mapped, the surface compositions and temperatures will be measured, atmospheres will be probed and new discoveries will be made.

A love note from Pluto

It’s also been wonderful to see the public become so enthralled with the latest image from Pluto. Humans are incredibly good at spotting patterns and it seems that Pluto wears his heart on his sleeve for us.

 

I’m also equally intrigued to discover that the smooth part of Pluto’s heart is made of carbon monoxide ice. This was already known from ground-based observations, except never before seen in such detail. It’s reassuring to have a good match between the old and new data.

But look again … is it a heart or something entirely different stealing the show?

 

 

Tanya Hill is Honorary Fellow of the University of Melbourne and Senior Curator (Astronomy) at Museum Victoria.

This article was originally published on The Conversation. Read the original article.

The mighty mite, part II

Author
by Patrick
Publish date
15 June 2015
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Mites form relationships with a great variety of other animals, ranging from neutral partnerships (commensalisms) to obligate co-dependencies (mutualisms). In the second category, female carrion beetles (such as Nicrophorus species) carry mites under their wings. They release the mites onto carrion before laying their eggs; the mites move out and feed on flies’ eggs, the maggots of which would compete with the carrion beetle larvae for food.

 
spider with mites Hundreds of small grey laelapid mites (looking like grey dots) living in the cracks and crevices of a Sydney Funnelweb (Atrax robustus). Because of the (usually illegal) trade in tarantulas for the pet industry, Australian mites have been discovered on African tarantulas in Britain.
Image: Patrick Honan
Source: Museum Victoria
 

Many mites hitchhike to new feeding grounds in a type of commensalism known as phoresy. Depending on the habitat and lifestyle of the host, some groups of animals are common vessels for phoretic mites, particularly burrowing animals such as certain passalid beetles, funnelwebs and trapdoor spiders.
 
Mites on a beetle Mites on the underside of a passalid beetle. The mites are clustered in locations where the beetle cannot reach and dislodge them, such as between the front legs. Each passalid beetle may have 500 or more mites and other animals living on it.
Image: Patrick Honan
Source: Museum Victoria
 

Lots of mites are parasitic, a very one-sided relationship which involves sucking the blood of their prey. It is often difficult to find an insect or spider in the bush that is mite-free. Heavy infestations of mites are usually a host’s secondary problem—the primary problem (whether it’s infection, lack of food or extreme environments) makes them more vulnerable to mite attack. This relationship is an ancient: last year scientists discovered a mite in 50-million-year-old Baltic amber, still attached to its ant host.
 
mites on a grasshopper Heavy infestation of parasitic mites on the thorax of a Prickly Katydid (Phricta spinosa)
Image: Patrick Honan
Source: Museum Victoria
 

Live Exhibits staff at Melbourne Museum regularly venture into the bush to collect invertebrates for breeding and display. We try to avoid mite-infected insects, partly because it’s an indication of an unhealthy specimen, and partly because mites brought into a captive environment can quickly breed out of control and overwhelm their hosts. Mites also regularly stow away in bedding, food or enclosure substrate.
 
beetle with mites Acarid mites living on a captive-bred female Rhinoceros Beetle (Xylotrupes ulysses). Several thousand mites were living on the underside of this beetle, originating from dry dog food fed to the beetle larvae.
Image: Patrick Honan
Source: Museum Victoria
 

The Varroa Mite (Varroa destructor), is the biggest threat to the Australian honeybee industry, the last Varroa-free bastion in the world. Conversely, other mites help control introduced weeds in Australia, such as the Broom Gall Mite (Aceria genistae) that feeds on English Broom (Cystisus scoparius).
 
mites on wasp larva Hundreds of female parasitic mites feeding on a European Wasp larva (Vespula germanica) in a laboratory culture. Each mite holds hundreds of eggs.
Image: Patrick Honan
Source: Museum Victoria
 

Try as you may, there’s no escaping mites. To paraphrase the nursery rhyme:

Big mites have little mites
Upon their backs to bite em
And little mites have lesser mites
And so, ad infinitum.

Links

The mighty mite part I

The mighty mite part I

Author
by Patrick
Publish date
10 June 2015
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You may not realise it, but tiny mites are ubiquitous—about 50,000 species of mites have been described around the world, with an estimated half a million species yet to be described. They range in size from eriophyid mites at 125 micrometres in length, to velvet mites, the giants of the mite world, at 20mm long.

Red furry mite A Red Velvet Mite (Trombidiidae) from Victoria’s Alpine National Park.
Image: Patrick Honan
Source: Museum Victoria
 

They live in every terrestrial and aquatic habitat in the world, in your house and even on your body. About three quarters of humans have Eyelash Mites (Demodex species) living in their hair follicles and sebaceous pores around the eyelids, eyebrows and nose. Mites also live in the ears of our pets and all over our farm animals. We eat mites regularly, either raw or cooked with our vegetables, in quantities deemed acceptable by food regulators.

Red mite on leaf An erythraeid mite from Rowville, Victoria. These mites are commonly found wandering on eucalypts in bushland around Melbourne.
Image: Patrick Honan
Source: Museum Victoria
 

About 250 species of mites can affect human health, the most pervasive being the House Dust Mite (Dermatophagoides species) which feeds on dander (dead skin flakes). Its poo is the dust we ultimately breathe in. About 10% of people are allergic to this dust, and the average bed may be home to up to 10 million mites. Other mite species are also responsible for scabies and a great range of itches (grain itch, grocer’s itch, copra itch, straw itch, and so on).

But mites aren’t all bad by any means; in fact if it weren’t for them most ecosystems would collapse. They create and maintain soil, and many plant species support ‘mite houses’ (called domatia) on their leaves, providing homes for resident mites that in return keep the leaves clean. While good mites help the plants, the Two-spotted Mite (Tetranychus urticae) attacks and can destroy hundreds of different crops cultivated by humans, and is controlled in glasshouses around the world by the Predatory Mite (Phytoseiulus persimilis).

webbing on plant Two-spotted Mites (Tetranychus urticae) on an indoor plant. The webbing is produced by this species when their populations are high, to protect themselves and their eggs.
Image: Patrick Honan
Source: Museum Victoria
 

The Californian Mite (Paratarsotomus macropalpis) has recently overtaken the Australian Tiger Beetle (Megacephala australis) as the fastest animal on earth, at least in proportion to body size. Humans can run up to 10 bodylengths per second (BLS), the Cheetah up to 20 BLS and the previous record holder, the Tiger Beetle, can move at 171 BLS across the salt flats in north west Victoria. The Californian Mite moves at 322 BLS, the equivalent of a human being running at more than 2,000km per hour.

Mite under a log A trombidiid mite living under a log in wet rainforest at Wilsons Promontory, Victoria.
Image: Patrick Honan
Source: Museum Victoria
 

Mites are also the strongest animals on earth, again in proportion to size. The Tropical Moss Mite (Archegozetes longisetosus), which occurs in Australia and elsewhere, has holding forces in its claws equivalent to 1180 times its own weight, compared to the usual example of ants (50-100 times their own weight) and Rhinoceros Beetles (850 times). That’s the equivalent of an adult human male with a holding force of 90 tonnes.

The life cycles of mites are often quite bizarre. In one group of mites (Adactylidium species), the males die before or just after they are born, and the females are born pregnant and eat their own mothers alive from the inside out. Others live on or in a number of hosts, their body shape and number of legs varying throughout their lives.

Harvestman with red mite A red mite (Leptus species) piggybacking on a Harvestman (Opiliones) in the rainforests of Far North Queensland.
Image: Patrick Honan
Source: Museum Victoria
 

The word ‘mite’ originates from Old English, meaning ‘very small animal’. Mites are remarkably diverse in habitat and life cycle, easily the largest group of arachnids on earth. Although sometimes troublesome, we are dependent upon them in so many different ways, and if they weren’t so small they might take their rightful place in our psyche as some of the world’s most amazing animals. 

The Honourable Joan Kirner

Dr Greene is the CEO of Museum Victoria.

Museum Victoria mourns Joan Kirner, the former Premier of Victoria, who served as a member of the museum's governing body from 2003 to 2012.

Joan Kirner speaking at the Joan Kirner speaking at the celebration of the 21st birthday of Scienceworks.
Source: Museum Victoria
 

Joan's first involvement with the museum occurred during her time as Premier of Victoria when she opened Scienceworks, an investment in the scientific life of the State that proved very forward-thinking.

Joan was an enthusiastic supporter of Museum Victoria. Just last week she was talking about ways in which she might help with one of the museum's current projects that is providing visibility to the role of women on farms in Australia. Her enthusiasm for efforts to recognise and encourage women in all aspects of public and personal life extended to many other aspects of social justice, including the rights of Aboriginal Australians. She was a member of the museum's Aboriginal Cultural Heritage Advisory Committee, and the development of the First Peoples exhibition in Bunjilaka was dear to her heart.

Joan's passions extended to wildlife, and particularly birds. She and Ron, her husband, went on camping trips that would bring them to places rich in birdlife until ill-health curtailed that activity. She was a great advocate for opportunities for the museum to display its rich collections of natural science specimens, culminating in the opening of the award-winning Wild: Amazing animals in a changing world at Melbourne Museum. As someone who placed the education of young people high on any agenda, the museum's ability to reach and inspire hundreds of thousands of children was a source of considerable pleasure. Joan was also on the Immigration Museum Advisory Committee and was a strong advocate for youth engagement which resulted in the Talking Difference project.

I enjoyed working with Joan Kirner enormously during her nine years (the maximum term) as a Board member. Her enthusiasm was matched by her keen intellect: she was a constant source of wisdom. When she stepped down from the Board, Joan was appointed an Honorary Life Fellow of Museum Victoria and she continued to take a close interest in its progress. Her insights into the politics and personalities of Victoria were always valuable and frequently amusing. She was held in high regard by everyone associated with Museum Victoria and we will miss her greatly.

Junior Dino Experts

Author
by Kate C
Publish date
28 May 2015
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The very young are most susceptible to dino fever. In children, the symptoms are very clear: compulsive recitation of dinosaur names, a predilection for dinosaur motifs on every surface, a hyper-alert state anytime they 're near a fossil. In extreme cases, kids can reel off all the scientific inaccuracies in Jurassic Park. Fortunately, some kids never shake dino fever and they grow up to be palaeontologists.

Wayne Gerdtz curated two Melbourne Museum exhibitions that draw in lots of visitors: 600 Million Years: Victoria evolves and Dinosaur Walk. A chronic case himself, Wayne recalls a childhood filled with lurid dinosaur books. Since he grew up in remote country Victoria, his visits to the museum in Melbourne were infrequent and much anticipated. One prized souvenir from the 1970s exhibition Dinosaurs from China still hangs in his house. His palaeontological interests moved on to extinct mammals but dino fever still beats strongly in his heart.

 

Another trained palaeontologist, science educator Priscilla Gaff, thanks her Nana for fostering her interest in dinosaurs. From the age of 5 or 6, her Nana took her to the old museum every holidays. Cilla is still so afflicted by dino fever that she planned her upcoming overseas trip to include a visit to Mary Anning's old fossil-collecting grounds in Lyme Regis. (Anning herself hunted for fossils from a very young age and uncovered the first complete ichthyosaur skeleton when she was just 12, soon after her brother found the beast's skull.)

Mary Anning Portrait of Mary Anning with her dog Tray and the Golden Cap outcrop in the background. The painting is at the Natural History Museum, London.
Image: Credited to 'Mr. Grey'
Source: Public domain via Wikimedia
 

Now we seek the next generation of palaeontologists through the Junior Dino Expert Competition at Scienceworks. We are looking for children between the ages of 3–12 years of age who have a severe case of dino fever and a passion for sharing their dinosaur knowledge with others.  Applicants need to submit an application form and a creative response that demonstrates their love of dinosaurs. This could be a video, piece of writing, slide show, collage or anything else.

Junior Dino Expert Competition promo Junior Dino Expert Competition
Image: MV
Source: Museum Victoria
 

For details on how to enter, and a list of excellent prizes, visit the Junior Dino Expert Competition page. Be sure to have your entries in by Monday 8 June!

Links:

Tyrannosaurs – Meet the Family at Scienceworks

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