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DISPLAYING POSTS FROM: Nov 2011 (17)

Fun with funnel-webs

Author
by Colin
Publish date
21 November 2011
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Comments (3)

Bugs Alive! highlights not only the highly venomous Sydney funnel-web spider (Atrax robustus), but also the diversity of Australian funnel-web spiders. There are currently 35 known species in Australia, and it is likely that more await description. Many southeastern Australians may not be aware that they too may have funnel-web spiders living in their backyard. Don't panic, aside from the Sydney Funnel-web, the majority of Australian funnel-web spiders do not pose a threat to us. In fact, most spiders are harmless. Of the estimated 10,000 species (only about 3000 have been named) that are native to Australia, only two pose a serious threat to human life.

The Australian funnel-web spider family Hexathelidae belongs to the primitive infraorder Mygalomorphae, which includes the trapdoor spiders, mouse spiders, and the large theraphosids (better known as tarantulas). Mygalomorphs can be distinguished from other spiders by having paraxial or parallel fangs (chelicerae), and an extra pair of book lungs.

funnel-web burrow A typical funnel-shaped entrance to a funnel-web spider burrow.
Image: Colin Silvey
Source: Museum Victoria
 

To keep our spiders healthy and stress-free, we rotate them off display so that each individual is on show only one month per year. To do this we must collect spiders from the wild to ensure that we have enough to keep the rotation flowing smoothly. Chloe wrote in April about a previous spider-hunting trip. Last week we went to the Nariel Valley in northwest Victoria, Violet Town in central Victoria and the Central Highlands (Narbethong-Acheron Gap, Victoria) to collect three different species of funnel-web spiders.

Alpine Wolf Spider Not all burrows contain funnel-web spiders. This one we dug up was occupied by this beautiful Alpine Wolf Spider (Lycosidae).
Image: Colin Silvey
Source: Museum Victoria
 

Our first stop was the Nariel Valley where we searched for the mighty Alpine Funnel-web (Hadronyche alpina). This is a newly-described species that is found, you guessed it, in the alpine environments of Victoria and N.S.W. They are impressive spiders with big black hairy bodies, and a mean temper to boot!

After collecting our quota of H. alpina, we drove west towards Violet Town, near Benalla, in search of the Central Victorian Funnel-web, H. meridiana. We had heard reports that a resident in Violet Town had found some in her backyard, and upon contacting her, she agreed to us collecting them. After lifting some old carpet lying on the ground, we found burrows galore! It didn't take us very long to collect all the spiders we needed before setting off to track down our third target species H. modesta.

man digging up spider burrow Exciting stuff! Live Exhibits keeper Adam Elliott excavating a burrow belonging to H. meridiana.
Image: Colin Silvey
Source: Museum Victoria
 

Funnel-web spider in burrow Funnel-web spider (H. meridiana) about to be removed from her burrow.
Image: Colin Silvey
Source: Museum Victoria
 

funnel-web spider threat display Hadronyche meridiana showing off her threat display. If you look closely you might be able to see the paraxial chelicerae that define the mygalomorph spiders.
Image: Colin Silvey
Source: Museum Victoria
 

H. modesta, or the Southern Victorian Funnel-web can be found around Victorian cool temperate sclerophyll forests ranging from just north of Melbourne, to the eastern end of the Strzelecki Ranges in South Gippsland. Unfortunately, after much searching, we failed to find any H. modesta. We are always on the lookout for any reports of glossy black spiders that burrow, so, if you live in the eastern or northeastern suburbs and see this spider around, let us know and we might come pay you a visit!

Further reading:

Walker, K.L., Yen, A.L. & Milledge, G.A. 2003. Spiders and Scorpions Commonly Found in Victoria. The Royal Society of Victoria. (Beginner)

Grey, M. R. 2010. A Revision of the Australian Funnel Web Spiders (Hexathelidae: Atracinae). Records of the Australian Museum. Vol. 62: 285–392. (Advanced)

Meet Me at the Museum

Author
by Dr Andi
Publish date
18 November 2011
Comments
Comments (9)

Do you have about five minutes? Great! Come and “Meet Me at the Museum”. It’s a new online video series about items from the Museum Victoria collection.

Objects and specimens always have a few fascinating people moments. We glimpse at those moments and marvel at the objects.

Here's episode one.

 

Watch this video with a transcript.

Postgraduate trifecta

Author
by Kate C
Publish date
14 November 2011
Comments
Comments (1)

Congratulations to Katie Smith, Natalie Calder and Skipton Woolley for handing in their postgraduate theses in the last fortnight. All three have done major pieces of research that combined new field studies with Museum Victoria Natural Sciences collections.

For her PhD, Katie Smith assessed the hybrid zone between two closely-related south-eastern Australian tree frogs, Litoria ewingi and Litoria paraewingi. A hybrid zone is an area where the geographic distribution of two species overlap in a narrow contact zone. They subsequently share habitat and sometimes cross-breed.

Two frogs Top: Litoria ewingi calling. Bottom: Litoria paraewingi. Can you spot the difference between these two species?
Image: Katie Smith | Fran Lyndon-Gee
Source: Museum Victoria
 

In the 1960s, Murray Littlejohn first reported hybridisation in these species in the Kinglake area, collecting specimens and recordings of the male advertisement calls in the 1960s. Katie built upon Murray's work, performing genetic and acoustic analysis on the original specimens and recordings and recent samples to compare the hybrid zone then and now. Says Katie, "it makes you realise what a good job Murray did! It's amazing that he even worked out they are different species because their appearance and calls are so similar."

recording frog calls in the field Main: Murray Littlejohn recording frog calls in the 1960s. Inset: Katie Smith recording frog calls for her PhD.
Source: Murray Littlejohn | Museum Victoria
 

Katie found that the hybrid zone is quite stable which is particularly interesting because the Kinglake area has changed dramatically over the decades through agricultural and residential development. Her fieldwork, completed before the 2009 bushfires, can't comment on the effect of fire on the hybrid zone but she hopes that ongoing surveys will keep an eye on the situation. When she handed in her thesis, her colleague Susi made a special batch of hybrid frog cupcakes to celebrate!

frog cupcakes Hybrid frog cupcakes for afternoon tea!`
Image: Susi Maldonado
Source: Susi Madonado
 

Natalie Calder's Masters thesis investigated how larval fishes use tide cycles to disperse in Port Phillip Bay. She worked at Governor Reef, near Indented Head on the Bellarine Peninsula, measuring where these tiny hatchlings place themselves in the water column.

As Nat explains, "Upon hatching larvae are translucent, lack scales and are usually less than 1mm long. Studies throughout the first half of the 20th century assumed that larvae were passive particles, at the mercy of tides and currents, with little or no control over where they dispersed."

Three larval fishes Three larval fishes. Top: Zeidae (dory family) without fins, jaws or pigmented eyes. Middle: Hemiramphidae (garfish or halfbeak family) in relatively late stage of development, with visible muscle bands. Bottom: Triglidae (gunard or sea robin family) with partially-developed fins, well-developed eyes but still-visible egg yolk sac.
Image: Natalie Calder
Source: Museum Victoria
 

Since then, scientists have observed that fish larvae display more complex behaviour, and Nat's research contributes to this body of knowledge. She found that fish larvae are quite selective and effectively 'surf' the tides in and out of Port Phillip Bay by exploiting properties of the currents. They rise in the water column to catch fast-moving surface waters during incoming tides, ensuring they stay in the bay rather than be swept out to sea. This better understanding of how larval fish disperse could help ensure the network of marine protected areas are sufficiently connected to keep fish populations healthy.

Another major piece of Masters research with implications for marine reserves was completed by Skipton Woolley, who used marine worms called polychaetes to model the biodiversity of large-scale ecological systems. Using data from museum collections and from new fieldwork in the Kimberley region of Western Australia, he tested whether polychaetes are a good group to use when assessing biodiversity. The idea is that it's not often practical to count every species in an ecosystem, but if the diversity of one group correlates with biodiversity overall, they become a handy indicator that can be used to compare between regions.

By examining 342 species from seven families, he found that that polychaetes are indeed a useful group, because where you find numerous species of polychaetes, you find numerous species of other animals, such as echinoderms and crustaceans. Thus, concludes Skip, "worms are amazing!"

scaleworm A scaleworm from Skip's Masters project, Iphione muricata (family Polynoidae). The numerous white hairy structures, or chaetae, are what give this group their name - the polychaetes.
Source: Museum Victoria
 

Amazing too are our students who contribute so much to the museum's research work. Well done Katie, Nat and Skip!

Links:

Information for prospective students

MV News: Victoria frogs and bushfires

WA Museum: Marine Life of the Kimberley Region

Hunting for herpetiles

Author
by Kate C
Publish date
11 November 2011
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Comments (0)

During the recent Prom Bioscan biodiversity survey of Wilsons Promontory, Dr Joanna Sumner led the herpetology (reptiles and amphibians) group. She and her troops - Katie Smith, Claire Keely, Susi Maldonado, Maggie Haines and Parks Victoria's Steve Wright – used a combination of trapping and active searching to find nine skink species, three elapid snake species and five frog species over several survey sites.

  Claire and Susi doing fieldwork Claire and Susi checking funnel traps opposite Lilly Pilly Gully carpark.
Image: Jo Sumner
Source: Museum Victoria

Reported Jo,

We captured, tissue sampled and released 59 individual reptiles and amphibians. Tissue samples will be put in our frozen tissue collection and used in research on species identification of some these groups. The overall diversity of reptile species in the Prom is very low compared to other areas in Australia. We sighted all three snakes previously recorded, 50% of known frog species and 75% of skinks known to the area. We did not record any of threatened species previously recorded on the Prom however, such as Litoria raniformis and Egernia coventryi.

 

If you're ever wondered what herpetology fieldwork looks like, here's a video from Wilsons Prom where Jo explains how she traps skinks and takes tissue samples.

 

Watch this video with a transcript

Big Kids' Night Out

Author
by Frances
Publish date
10 November 2011
Comments
Comments (0)

This post is by Science Program Manager, Frances Haire.

On Saturday 5 November we held the inaugural Big Kids' Night Out at Scienceworks. Over 600 big kids took over what is usually the realm of little kids. They played in the exhibitions, took a trip through our galaxy in the Planetarium, saw a show about the science of alcohol and learned how to make the perfect layered cocktail.

Two men at Scienceworks exhibition. Two big kids playing in the little kids' Nitty Gritty Super City exhibition.
Image: Dylan Kelly
Source: Museum Victoria
 

In the Experiment Zone, 'Test your senses' checked our visitors' eye dominance. When you look at something with both eyes, each eye is looking from a slightly different angle. The brain then pieces the two images together to form one three-dimensional image. Most people have a dominant eye, which means that when the brain compiles information from both eyes, the view from the dominant eye is favoured.

To test your eye dominance, make a circle with your thumb and forefinger. With both eyes open, look at an object and centre it inside the circle. Shut one eye, then open it and shut the other. Did the object move out of the circle when you shut one of your eyes? If so, that eye that you shut is your dominant eye. If not, you have no dominant eye.

At Big Kids' Night Out we tested the eye dominance of 223 big kids. Of the men tested, 48% were right eye dominant, 49% were left eye dominant and 3% showed no dominance. In women, there was slightly more variance with 43% favouring their right eye, 51% their left and 5% showing no dominance.

Eye dominance test results A graph showing the results (in percentages) of our eye dominance test.
Source: Museum Victoria
 

The big kids were all old enough to vote but they played like they weren't! Some were reliving childhood excursions while others had never been to Scienceworks and grabbed the chance to visit while the galleries were child-free.

Man in Scienceworks exhibition A big kid testing his perception skills in the Perception Deception exhibition.
Image: Dylan Kelly
Source: Museum Victoria
 

Next up for adult programming at Museum Victoria is the Cross(X)Species Adventure Club edible cocktail extravaganza at Melbourne Museum on 1 December. Keep your ears and eyes open for the next adults-only event at Scienceworks.

Links:

Scienceworks

Big Kids' Night Out media release

Asteroid flyby

Author
by Tanya
Publish date
7 November 2011
Comments
Comments (3)

On Wednesday 9 November an asteroid is going to fly past Earth.

Vesta from Dawn spacecraft NASA's Dawn spacecraft was sent to the Asteroid Belt to obtain close-up images of Vesta.
Source: NASA
 

But not this one! This is a picture of Vesta, the third largest asteroid in the Asteroid Belt, located about 200 million kilometres away. This lovely picture was taken by the Dawn spacecraft, which is currently in orbit around Vesta. It shows what a large asteroid looks like from a distance of just 5,200km.

 

asteroid 2005 YU55
Radar image of the near-Earth asteroid 2005 YU55 when it was 2.4 million km away.
Source: NASA/Cornell/Arecibo
 

The asteroid that is going to fly past Earth is known as 2005 YU55. This radar image of the asteroid was made last year using the Arecibo Radar Telescope in Puerto Rico. At 400m across this near-Earth asteroid is over 1,000 times smaller than Vesta. Rather than having to send a spacecraft out to it, this asteroid is coming to us.

But there’s no need to go crazy - the closest the asteroid will get is 325,000 km from Earth. That’s just a little closer than the Moon which on average is 380,000 km away. It won’t pose any threat to Earth or have any noticeable gravitational effect. But we should get a great look at it.

NASA scientists will be using antennae from the Deep Space Network to bounce radio waves off the space rock. The data is then used to create a three-dimensional model of the asteroid and with the asteroid being so close it should provide us with a really detailed image so we can learn more about it.

Hundreds of asteroids have been observed using radar astronomy and the interesting thing is that asteroids can be so different. They come in all sorts of shapes and sizes, with some having very smooth surfaces and others being rough and textured. Radar astronomy can also be used to determine the composition of an asteroid and it's even discovered some asteroid moons.

Most importantly of all, radar astronomy gives us the best insight into an asteroid’s trajectory. That’s how we can work out that this near-Earth asteroid won’t harm us and provides the lead time to prepare for great science observations like this one.

I look forward to the day when astronauts will once again take the leap beyond Earth orbit. Many say that after the Moon, the next step for astronauts should be a near-Earth asteroid. The information that’s gathered now could one day be used to choose just which asteroid we'll be visiting.

Links

JPL’s Asteroid Watch Page

NASA’s Near Earth Object Program

About this blog

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

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