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DISPLAYING POSTS TAGGED: spiders (5)

Venom and phobias at SmartBar

Author
by Kate C
Publish date
23 July 2012
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SmartBar is returning to Melbourne Museum by popular demand! On 26 July from 6pm, the second adults-only SmartBar will focus on Mind and The Human Body. The Science and Life exhibitions will be open after dark with talks, displays, activities and music to boot.

The Live Exhibits crew were very popular at the first SmartBar and they are back again with a look at creatures that bite and sting, how venom interacts with the body, and how our minds can turn healthy wariness of venomous animals into debilitating phobias.

Australia is notorious for its venomous wildlife. Even our cute furry Platypus carries a poisoned spur that causes excruciating pain for any unfortunate human on its receiving end. But did you know that venom can have positive effects on humans too? The field of bioprospecting is uncovering new compounds from the venom of snakes, scorpions, centipedes and spiders that may help to treat cancer and many other diseases.

glowing scorpion Scorpions glow when viewed under ultraviolet light due to fluorescent chemicals in the cuticle. The bulb at the end of the tail can inflict a nasty sting.
Image: Patrick Honan
Source: Museum Victoria
 

Arachnophobia – the fear of spiders – is the most common phobia in western society. You might think it's simple evolutionary common sense to fear something that can harm you. However, the lives of the truly arachnophobic are governed entirely by their relationship with spiders, leading some to risk their lives by jumping from moving cars and out of upper storey windows. For others, every daily decision, from the car they drive to where they live, is based on avoiding eight-legged critters.

Huntsman spider on screen door Huntsman spider on your screen door - a welcome friend or nightmarish visitor?
Image: PG Palmer
Source: Image courtesy of PG Palmer, as licensed under CC BY-SA 2.0 Generic.
 

MV's manager of Live Exhibits, Patrick Honan, likes spiders – especially the big black hairy ones. He has helped people face their arachnophobia through cognitive behaviour therapy, followed by a controlled process of desensitisation called exposure therapy. He'll be speaking at SmartBar about the root cause of our fear of spiders, and whether it's justified. Whether you're fond or fearful of spiders, Patrick's stories are not to be missed.

SmartBar's Brain, Mind, Eyes, Drinks and DJ event is on for one night only on 26 July 2012. For more information or to buy tickets online, head over to the SmartBar What's On listing.

Links:

MV Blog: First SmartBar round-up

Faces of the north

Author
by Patrick
Publish date
9 March 2012
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Live Exhibits staff visited Cairns and Cape Tribulation in North Queensland in December to augment our live animal collection with fresh genetic stock. We met many interesting animals along the way, so here are a few portraits of the critters that came back with us to Melbourne Museum.

The Giant Mantid is one of the largest mantid species in Australia. They feed on a range of insects but are large enough to overpower small frogs and lizards. Giant Mantids are currently on display in Bugs Alive!.

giant mantid Giant Mantid, Heirodula majuscula.
Image: Patrick Honan
Source: Museum Victoria
 

Raspy crickets derive their common name from the fact that all known species, both male and female, can produce a rasping sound at all stages of development. There are more than 200 species of raspy crickets in Australia and new species are regularly discovered. This very large adult female has powerful jaws and, like all raspy crickets, a bad temper. She ate her way out of several containers on the journey from North Queensland, causing havoc wherever she went.

Raspy Cricket Raspy Cricket, Chauliogryllacris species.
Image: Patrick Honan
Source: Museum Victoria

A male Golden Huntsman, probably the largest huntsman in Australia and generally considered the second largest in the world. This species sometimes causes panic when it enters houses, but like most huntsmans it is relatively harmless.

Golden Huntsman spider Golden Huntsman, Beregama aurea.
Image: Patrick Honan
Source: Museum Victoria

Net-casting Spiders are famous for their ability to spin perfectly rectangular silken nets, about the size of a postage stamp. These nets are thrown over passing prey as the spider sits suspended above an insect pathway. In honour of their enormous eyes, they are also known as Ogre-Faced Spiders.

Net-casting Spider Net-casting Spider, Deinopis bicornis.
Image: Patrick Honan
Source: Museum Victoria
 

French's Longicorn is one of Australia's larger beetle species. This one was found in a small mating aggregation on a strangler fig in the rainforest at night. Longicorns are characterised by kidney-shaped eyes which wrap around the base of the antennae.

French's Longicorn beetle French's Longicorn, Batocera frenchi.
Image: Patrick Honan
Source: Museum Victoria
 

The spiny legs of the Serrated Bush Katydid give it both its common and scientific name. Adults are always green, but nymphs may be red, brown or violet, depending on the colour of the leaves on which they feed. Males produce a short, loud call which is commonly heard in the rainforest at night. Another katydid, the Kuranda Spotted Katydid, is one of the larger and more robust of this group in Australia. The nymphs closely resemble ants, which may afford them some protection against predators. The eggs are glued to dead twigs by the female using a short, thick ovipositor.

katydids Left: Serrated Bush Katydid, Paracaedicia serrata. | Right: Kuranda Spotted Katydid, Ephippitytha kuranda.
Image: Patrick Honan
Source: Museum Victoria
 

These creatures, and many more, can be seen every day in Bugs Alive! at Melbourne Museum.

Spider city

Author
by Mark Norman
Publish date
7 December 2011
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Mark is Head of Sciences at Museum Victoria. He's reporting back from Neds Corner in this series of blog posts.

One of the priority groups of animals for the Bush Blitz surveys is the primitive mygalomorph spiders, such as trapdoor spiders and tarantulas. This group of spiders have large fangs that point down and can only be used to pin and pierce their prey. The 'modern' spiders (araneomorphs) have fangs that turn towards each other, so can be used more easily to grab their prey. We found only one small mygalomorph spider species.

Mygalomorph spider Mygalomorph spider
Image: M Norman
Source: Museum Victoria
 

Wolf spiders are the other focus group for these surveys and we found them everywhere. Dr Barbara Baehr from Queensland Museum was the wolf spider expert on the team. On night walks the blue eye shine of hundreds of wolf spiders can be seen over the ground and in the trees. Some larger ones build trapdoors over their burrow, complete with a perfect hinged lid.

Wolf spider and burrow Left: Wolf spider | Right: Wolf spider burrow with trapdoor
Image: Patrick Honan | Mark Norman
Source: Museum Victoria
 

The huntsman spiders here were very impressive, being among the largest in Australia with the females reaching 20cm across. Close-up images showed that many had small red mites crawling over their bodies.

huntsman spider Huntsman spider
Image: David Paul
Source: Museum Victoria
 

A Redback Spider nest was found by BHP participant Paul Simper where a large female was guarding two round egg masses while the tiny attendant male sat nearby.

Redback Spider family A Redback Spider family - the large female is in the centre, with the small male to the left and an egg sac to the right.
Image: David Paul
Source: Museum Victoria
 

The list of other spider types at Neds Corner is long, and includes ant spiders, ant-mimicking spiders, jumping spiders, orb weavers, social spiders, crab spiders and cellar spiders.

Ant spider Ant spider (family Zodariidae).
Image: Mark Norman
Source: Museum Victoria
 

Bush Blitz is a biodiversity partnership discovery program between the Australian Government, BHP Billiton and Earthwatch Australia, that aims to document the plants and animals across Australia's National Reserve System. Museum Victoria also participated in Bush Blitz at Lake Condah in March 2011.

Links:

Parks Australia blog

Bush Blitz

Neds Corner Station

Daddy long-legs

Author
by Tim Blackburn
Publish date
20 September 2011
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Recently, a visitor to Bugs Alive! asked me whether daddy long-legs are spiders. The answer depends on what one is referring to when employing the term "daddy long-legs". It can be used to refer to a group of close relatives of spiders known as the harvestmen, which are arachnids (as are spiders) but are nonetheless not spiders. It can also be used to refer to crane flies, which are insects and not arachnids. The term is, however, most commonly used in Australia to refer to a species of spider known scientifically as Pholcus phalangioides. P. phalangioides is also sometimes known as the grandaddy long-legs, the cellar spider or the house spider, and is commonly found in houses in its irregularly structured webs which it often weaves in dark areas, such as under desks and behind bookshelves, or in the corners of ceilings in disused rooms.

The spider Pholcus phalangioides The spider Pholcus phalangioides is commonly referred to as the "daddy long-legs".
Image: Tim Blackburn
Source: Museum Victoria

Harvestmen, however, live in vastly different environments than does Pholcus phalangioides. They have been found in moist leaf litter, under rotting logs, under rocks and under the bark of trees. Unlike spiders, which are classified under order Araneae, harvestmen are classified under order Opiliones. The cephalothorax (the anterior/front body segment) of harvestmen is fused broadly with the abdomen (the posterior/rear body segment) to form a body which seemingly lacks a waist, whereas there is a distinct division between these two body segments in spiders. Furthermore, harvestmen have two eyes which are each positioned on the end of stalk-like projections found in a region approaching the top of the cephalothorax, as compared with spiders, which generally possess eight eyes attached directly to the anterior (front) region of the cephalothorax.

Harvestman specimen
Harvestmen are commonly referred to as “daddy long-legs” but they are not spiders. The above specimen’s second right leg appears blurry because harvestmen use their second pair of legs much like antennae, constantly waving them around.
Image: Tim Blackburn
Source: Museum Victoria
 

Harvestman on a leaf The two body segments of harvestmen are fused to give the appearance of a body with a much reduced or absent waist.
Image: Patrick Honan
Source: Museum Victoria
 

Unlike spiders, harvestmen do not produce silk, and they are omnivorous, having been known to feed on other invertebrates, plant matter, and the rotting carcasses of birds and mammals. They are non-venomous but can chew their food, whereas spiders must use venom injected by their fangs to convert their prey to liquid which they drink. Male harvestmen have a penis, which facilitates the direct transfer of sperm (from the genital region) to the female, whereas male spiders must use their pedipalps (which encircle the mouth) to do this indirectly.

Pholcus phalangioides
The distinct division between the two body segments of Pholcus phalangioides gives the appearance of a waist.
Image: Tim Blackburn
Source: Museum Victoria
 

Pedipalps of Pholcus phalangioides The bulbous terminations to the male’s pedipalps of Pholcus phalangioides are used to transfer his sperm to the female.
Image: Tim Blackburn
Source: Museum Victoria
 

pedipalps of harvestmen The pedipalps of harvestmen are used for food-handling only as males have a penis which enables the direct transfer of sperm to females.
Image: Tim Blackburn
Source: Museum Victoria
 

The Live Exhibits department sometimes has harvestmen in its collection. We are considering the merits of putting them on display in the near future, possibly to illustrate the differences between spiders and harvestmen.

Harvestman. A harvestman I recently found inside a house, oddly enough.
Image: Tim Blackburn
Source: Museum Victoria
 

Further reading:

Harvey, M. S. And Yen, A. L. (1997) Worms to Wasps. Oxford University Press, Oxford: p. 86-87.

Milledge, G. A. and Walker, K. L. (1992) Spiders Commonly Found in Melbourne and Surrounding Regions. Royal Society of Victoria, Melbourne.

Links:

Question of the Week: Daddy long-legs spiders

Harvestmen (CSIRO)

Harvestmen (Wikipedia)

Pholcus phalangiodes (Wikipedia)

Pholcidae (Wikipedia)

Live Exhibits’ trip to the Alps

Author
by Chloe
Publish date
13 April 2011
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This guest post is by Chloe, a Live Exhibits keeper at Melbourne Museum.

At Live Exhibits we like to keep a range of funnel-web species. This way we can represent not only the infamous Sydney Funnel-web spider, but the majority of Australian funnel-web species in our exhibits.

As it had been six years since Live Exhibits’ last trip to Nariel Valley, it was time for Jessie, Patrick and I to pack up the car and head off on a field trip in the to find some Alpine Funnel-webs (Hadronyche alpina).

Alpine Funnel-web Alpine Funnel-web, Hadronyche alpina.
Image: Chloe Miller
Source: Museum Victoria
 

Local resident Mrs Brown originally alerted the museum’s Discovery Centre to the presence of a population of Alpine Funnel-webs in the Nariel Valley and more particularly her front lawn. Young funnel-webs emerge from their mother’s burrow, find an attractive burrow site, and then burrow down, which makes for high density populations. For us, this leads to quick collection of multiple specimens.

After finding three funnel-webs around our campsite it was time to head off to Mrs Brown’s place, where she showed four large burrows. We started digging holes in the mud more than 30cm deep, a process much more lengthy than expected, using only a desert spoon to dig, trying not to destroy Mrs Brown’s lawn or injure the spiders. Finally we produced four plump female funnel-webs (which were less than happy about being disturbed) then we balanced them on a spoon to be transferred into their new glass homes.

Alpine Funnel-web Alpine Funnel-web, Hadronyche alpina
Image: Chloe Miller
Source: Museum Victoria
 

Soaking wet with seven funnel-webs under our belt and no sign of any more, it was time to head off to Omeo.

The following day drove up the windy, fog-covered hills to Mt Hotham, where we began our search for Alpine Thermocolour Grasshoppers (Kosciuscola tristis), Alpine Blistered Pyrgomorphs, (Monistria concinna), Mountain Katydids (Acripeza reticulata) and Alpine Katydids (Tinzeda albosignata).

Alpine Katydid & Alpine Thermocolour Grasshopper Left: Alpine Katydid, Tinzeda albosignata. Right: Alpine Thermocolour Grasshopper Kosciuscola tristis.
Image: Alan Henderson
Source: Museum Victoria
 

On warmer days these invertebrates would be sitting up on small bushes and grass clumps, enjoying the sun. However on cooler foggy days, like the day of our visit, many of the invertebrates sink lower into the foliage to protect themselves against the elements, making our search a little harder and much wetter. Thankfully I had donned plastic pants and a rain coat which made the perfect outfit, although they didn’t help the situation in my boots, which contained enough water to fill a small lake.

Foggy Mt Hotham Foggy conditions for collecting invertebrates at Mt Hotham.
Image: Patrick Honan
Source: Museum Victoria
 

During the morning of searching, Patrick’s alter ego Taxon Boy didn’t let us down, helping us bag 48 Thermocolour Grasshoppers, 7 Alpine Katydids, 1 Mountain Katydid, 12 Alpine Blistered Pyrgomorphs and a female Alpine Wolf Spider (Lycosa sp.).

Alpine Wolf Spider, Lycosa sp.. Alpine Wolf Spider, Lycosa sp.
Image: Chloe Miller
Source: Museum Victoria
 

We made one final stop on our long drive back to the museum to collect some eucalyptus for our stick insects; here Taxon Boy also stumbled across some large Garden Orb-weavers (Nephila edulis) which you can now see on display in the Orb wall in Bugs Alive! at Melbourne Museum.

Garden Orb-weaver Garden Orb-weaver, Nephila edulis.
Image: Alan Henderson
Source: Museum Victoria
 

Links:

Infosheet: Spiders of Victoria 

MV Blog: TV Crew in Bugs Alive

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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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