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NEWS & VIEWS FROM MUSEUM VICTORIA

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.

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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

Roaming T-rex

Author
by Krystal
Publish date
21 May 2015
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Scotty the Tyrannosaurus rex got lost on his way to Scienceworks!

A shipping container holding this ancient predator and two baby dinosaurs has turned up on the Swanston Street Forecourt of Federation Square on its way to the Tyrannosaurs – Meet the Family exhibition.

Detail of T.rex puppet's teeth Scotty's teeth
Source: Erth Visual & Physical Inc
 

The dinosaurs will need to be let loose before being taken back to their family at Scienceworks. Come down and meet these incredible creatures as they roam around Federation Square on the afternoon of Saturday 23 May.

Follow Scotty’s movements on the Scienceworks Facebook page and through the hashtag #trexontherun on Twitter and Instagram.

T.rex puppet with a man and a girl Scotty looks scary, but he's pretty friendly.
Source: Erth Visual & Physical Inc
 

Tyrannosaurs – Meet the Family opens at Scienceworks on Saturday 23 May 2015. Dinosaur puppets by Erth Visual & Physical Inc.

MV at sea

Author
by Tim O'Hara
Publish date
4 May 2015
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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.

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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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