Sciences

DISPLAYING POSTS FILED UNDER: Sciences (244)

Sciences

Natural history - from animals to minerals, fossils to sea slugs. MV's scientists use the state's collections in important research.

The mighty mite, part II

Author
by Patrick
Publish date
15 June 2015
Comments
Comments (2)

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
Comments
Comments (2)

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. 

Junior Dino Experts

Author
by Kate C
Publish date
28 May 2015
Comments
Comments (0)

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

MV at sea

Author
by Tim O'Hara
Publish date
4 May 2015
Comments
Comments (2)

Dr Tim O'Hara is Senior Curator of Marine Invertebrates.

It is 3am, the night is jet black, the boat heaves with the swell, and a bunch of scientists and crew dressed in full wet-weather gear are silently standing, waiting on the back deck. There is always a sense of excitement as new samples are hauled in. What bizarre deep-sea creatures will be brought up? Perhaps this time we will see the enigmatic mushroom-shaped Dendrogramma, an animal (apparently) that has confounded all efforts at classification since its first collection by Museum Victoria in 1986. Or maybe the massive sea-lice that can devour a dead whale? Or just seafloor life in incredible abundance?

Large blue and white Investigator vessel The Marine National Facility research vessel Investigator at the CSIRO wharf in Hobart.
Image: Tim O'Hara
Source: Museum Victoria

Ship's crew using machinery on deck Deploying the Smith McIntyre grab.
Image: Tim O'Hara
Source: Museum Victoria
 

On Easter Tuesday, four science staff and students from Museum Victoria (Di Bray, Mel Mackenzie and Skip Woolley and I) joined scientists around Australia on a trial voyage of Australia’s brand new research vessel, the Investigator. The idea was to test out all the gear necessary for deep-sea exploration, from iron box-like dredges, used for over 200 years to collect samples, to the high tech cameras that bounce above the seabed, worked in real time from a joystick and a bank of computer monitors in the bowels of the ship, thousands of metres above. We went south of Hobart into the Southern Ocean, specifically to look at life on underwater sea mountains in the Huon one of the Commonwealth’s recently declared marine reserves.

People in the Investigator vessel lab The sorting lab: Skip, Di and Mel facing Karen Gowlett-Holmes of CSIRO.
Image: Tim O'Hara
Source: Museum Victoria

Big camera rig on ship deck The towed deep-sea camera.
Image: Tim O'Hara
Source: Museum Victoria
 

But I had another motive to joining this trip. Next year in November I will be chief scientist of a voyage from Brisbane to Hobart that will survey Australia’s abyssal sea-plain (4000 m below sea-level). So I really wanted to learn all I could about the capabilities of the vessel and think about best practice scientific procedures to ensure we get the most out of the expedition.

The Investigator, run by the Marine National Facility funded by the Commonwealth Government, is a large (94 m), elegant and efficient platform from which to do deep-sea research. Diesel electric engines keep the noise down and high tech stabilisers prevent much of the pitch, yaw and roll that can make life miserable on smaller boats.

People on ship deck The crew deploying gear off the stern deck.
Image: Tim O'Hara
Source: Museum Victoria

Ship crew deploying gear Preparing for the next catch: MV staff in canary yellow facing Mark Lewis of from CSIRO with Mark McGrouther of the Australian Museum looking on.
Image: Tim O'Hara
Source: Museum Victoria
 

My main memories of the trip: dark thundery night skies, albatrosses, friendly company and lots of carbs to eat. All too soon we steamed back to another sunny day in Hobart. We didn’t find Dendrogramma – maybe next time.

Happy birthday field guide apps!

Author
by Nicole K
Publish date
30 April 2015
Comments
Comments (0)

One year ago today we launched eight very special apps – field guides to the fauna of every state and territory in Australia. What makes these apps so special? They were produced collaboratively by Australia's seven leading natural history museums. 

The suite of 8 Field Guide to Australian Fauna apps. The suite of 8 Field Guide to Australian Fauna apps.
Source: Museum Victoria
 

Together the seven museums produced descriptions and sourced images for over 2100 animals from terrestrial, freshwater and marine environments. The result was a suite of pocket-sized identification guides, that could be used by everyone, everywhere – and they're free.

It's been a big year for the field guide apps. They have won two international awards, a Best of the Web award and a Muse award, as well as the Northern Territory Chief Minister's award for Excellence in the Public Sector.

The apps are also highly regarded by the app stores. All 8 apps appear in iTunes' Education Collections, which feature their hand-picked recommendations for "students, teachers, parents and lifelong learners". iTunes calls these apps "indispensable tools that will inspire students in every classroom".

MV Collection Manager, Katie Smith, using the Field Guide app. MV Collection Manager, Katie Smith, using the Field Guide app.
Source: Museum Victoria
 

Over the past year, the apps have been used by the museums in school holiday activities, education programs, teacher training, community outreach and biological surveys. But we're most excited about how the public are using them – to identify animals and to learn more about Australia's amazing wildlife.

Students using Museum Victoria's app in the Forest Gallery at Melbourne Museum. Students using Museum Victoria's app in the Forest Gallery at Melbourne Museum.
Image: Mirah Lambert
Source: Museum Victoria
 

The apps have received glowing praise from their users and, since the launch, have been downloaded over 78,000 times. We're absolutely thrilled that the apps have been so well received and look forward to what the next year will bring.

The National Field Guide Apps Project was funded by an Inspiring Australia Unlocking Australia's Potential Grant. The project was a 2-year collaboration between: 

Transcribing field diaries

Author
by Nicole K
Publish date
19 March 2015
Comments
Comments (4)

Deep in Museum Victoria’s archives lie boxes of notebooks. Notebooks that contain a significant part of our museum’s history. They are the field diaries of our past curators and collection managers, produced on scientific expeditions to explore, research and discover the natural history of Australia (and beyond).

Field diaries from Museum Victoria's collection Field diaries from Museum Victoria's collection
Source: Museum Victoria
 

These field diaries are of great interest to both scientists and historians. They are filled with invaluable data, providing insights into past species’ abundance and distribution, as well as personal descriptions of the trials and wonders experienced on historic expeditions.

A photograph from Graham Brown's field diary: Mt Rufus, Tasmania (1949). A photograph from Graham Brown's field diary: Mt Rufus, Tasmania (1949).
Image: Graham Brown
Source: Museum Victoria
 

Despite the fascinating information contained within the diaries (and the interest in them), they are relatively inaccessible. They were handwritten, often in less-than-favourable conditions (picture a scientist, crouched in the bush, notebook balanced on knee).

Sketch from Allan McEvey's field journal of his expedition to Macquarie Island, 1957. Excerpt from Allan McEvey's field journal of his expedition to Macquarie Island, 1957.
Image: Allan McEvey
Source: Museum Victoria
 

We have therefore started a crowd-sourcing project to transcribe the field diaries in our collection. The pages of each diary are carefully digitised and then uploaded into DigiVol the Atlas of Living Australia’s volunteer transcription portal that was developed in collaboration with the Australian Museum. Once transcribed, the text in the diaries will be searchable. We can create lists of the species mentioned and use this information to better understand and conserve our precious biodiversity.

Our most recent transcription project is Allan McEvey's field diary of his expedition to Macquarie Island in 1957. Museum Victoria's Curator of Birds from 1955, McEvey had a passion for scientific illustration and his field diaries are filled with sketches of birds and other wildlife.

Sketches of Black-browed Albatross, <i>Diomedea melanophris</i>, from Allan McEvey's field journal of his expedition to Macquarie Island, 1957. Sketches of Black-browed Albatross, Diomedea melanophris, from Allan McEvey's field journal of his expedition to Macquarie Island, 1957.
Image: Allan McEvey
Source: Museum Victoria
 

The original diaries, along with their transcriptions, will eventually be available online via the Biodiversity Heritage Library (BHL), the world's largest online repository of biodiversity literature and archival materials.

The Australian component of BHL is managed by Museum Victoria and funded by the Atlas of Living Australia. The project has allowed us to digitise over 500 rare books, historic journals and archival field diaries. This represents over 12000 pages of Australia’s biological heritage that was previously hidden away in library archives.

Interested in becoming a transcription volunteer?

If you would like to help us unlock the observations in our historic field diaries, more information is available on the DigiVol website.

About this blog

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

Categories