Aug 2011

DISPLAYING POSTS FROM: Aug 2011 (15)

Desert rains trigger rat plagues

Author
by Karen Rowe
Publish date
3 August 2011
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Karen Rowe is a Research Associate at MV where she studies evolutionary ecology and behaviour in birds and mammals.

Record levels of rainfall in the Northern Territory have brought forth one of Australia’s rare and unique native mammals, the Long-haired, or Plague Rat (Rattus villosissimus). These herbivorous rats feed largely on stems and leaves and, with consistently high rainfall, large areas of the desert landscape have become lush with food. Coupled with an unusually high reproductive rate, where a single female can produce more than 200 young in one year, these rats are capable of large-scale population explosions leading to rapid dispersal over huge distances. They have even been documented moving as much as 3 km in a single night.

In the past, these rodents have spread across the arid regions of Australia, including eastern Western Australia, the Northern Territory, eastern Queensland and parts of South Australia. Historic plagues have been documented as far back as 1847, with others occurring in 1916-18, 1930-32, 1940-42, 1948, 1950-52, 1956, and 1966-69.

Once the plague recedes, they vanish almost as quickly as they arrived and during non-plague years, they become rare and hard to find, persisting in only a few locations.

Taking advantage of this unique opportunity to document the latest plague, I joined MV mammal curator, Kevin Rowe, and collections manager, Wayne Longmore, to try to find these rats in the Northern Territory, along the Finke River.

Kevin Rowe and Wayne Longmore MV curator, Kevin Rowe (left), and collections manager, Wayne Longmore (right), trapping rats in the desert rain.
Image: Karen Rowe
Source: Karen Rowe
 

We found them in abundance – nearly all of our live traps contained a long-haired rat, and one had two!

Rattus villosissimus caught along the Finke River Rattus villosissimus caught along the Finke River.
Image: Karen Rowe
Source: Karen Rowe
 

We even found part of the skeleton of one in a bird pellet – the undigested material regurgitated by a bird, particularly in birds of prey.

Bird pellet before dissection Bird pellet before dissection.
Image: Karen Rowe
Source: Karen Rowe
 

Bird pellet after dissection After dissection – most of the skull and jaw were intact (on left).
Image: Karen Rowe
Source: Karen Rowe
 

Long-haired rats build burrows in the sand, consisting of meters of tunnels with multiple entrances and exits. They use these burrows extensively, spending nearly 80% of their time underground.

Rattus villosissimus burrow entrance Rattus villosissimus burrow entrance.
Image: Karen Rowe
Source: Karen Rowe
 

At the Finke River site, the sandy soil made it easy to see footprints into and out of these burrows.

Rattus villosissimus footprints Rattus villosissimus footprints.
Image: Karen Rowe
Source: Karen Rowe
 

Kevin and Wayne are still on the hunt for the plague rat, hoping to find more populations in the Barkly Tablelands and central NT. By studying these rats from throughout the state and recording natural history data such as behaviour and habitat, as well as traits of the rats themselves, including age and reproductive state, we can better understand the ecology and biology of this unique, native, and (most of the time!) rare mammal.

Links:

MV Blog: On rats

Ancestral Power in Darwin

Author
by Jennifer Mattiuzzo
Publish date
2 August 2011
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Jen Mattiuzzo is an Exhibition Manager at Melbourne Museum who is on the team that assembled the Ancestral Power and the Aesthetic exhibition.

NAIDOC Week was the backdrop for a series of public programs and events for Museum Victoria’s travelling exhibition Ancestral Power and the Aesthetic. This exhibition includes stunning painted barks and ceremonial objects from the Donald Thomson Collection, all collected by Thomson during the 1930s and 1940s from central and eastern Arnhem Land.

Traditional Owners of these works travelled to Darwin from Arnhem Land to take part in floor talks and to welcome the exhibition.

The highlight of the week was the welcome celebration on Wednesday 6 July where Yolngu men and women from Milingimbi danced and spoke about the importance these sacred designs and stories to an enthusiastic audience of locals and tourists. They came to pay respect to their ancestor, Harry Makarrwala, who painted one of the works in the exhibition.

Ancestral Power and the Aesthetic is on display at the Museum and Art Gallery of the Northern Territory until 11 September 2011.

This exhibition is supported by Visions of Australia, an Australian Government program supporting touring exhibitions by providing funding assistance for the development and touring of Australian cultural material across Australia.

Janice Wungurrkthun and Isobel Malulawuy Gaykamangu
Janice Wungurrkthun and Isobel Malulawuy Gaykamangu paint up before the performance
Image: Samantha Hamilton
Source: Museum Victoria
 

Children during the welcome celebration
Children danced alongside their parents and grandparents during the welcome celebration
Image: Samantha Hamilton
Source: Museum Victoria
 

Dancing at the entrance to MAGNT
Dancing begins at the entrance to MAGNT before moving into the exhibition space.
Image: Samantha Hamilton
Source: Museum Victoria
 

Bobby Makurrminya Dhurrwuy
Bobby Makurrminya Dhurrwuy leads.
Image: Samantha Hamilton
Source: Museum Victoria
 

Relaxing after the performance Relaxing after the performance.
Image: Samantha Hamilton
Source: Museum Victoria
 

Links:

MV Blog: Ancestral Power opens in Benalla

MV News: Ancestral Power and the Aesthetic

Bug of the Month

Author
by Jessie
Publish date
1 August 2011
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Comments (0)

The stars of the Bugs Alive! aquatic display Green Diving Beetles (Onychohydrus scutellaris) are remarkable for their ability to store air and dive underwater to hunt food and find mates. They are found Australia-wide and on warm nights are attracted to lights. Recently on the Gold Coast there was a report of thousands of these beetles coming into the lights on the foreshore and the ground around the lights was a black moving mass.

green diving beetle Adapted to a life in the water, Green Diving Beetles have streamlined bodies, paddle like hind legs with swimming hairs and an amazing ability to store pockets of air so they can dive under water for extended periods of time.
Image: Alan Henderson
Source: Museum Victoria
 

Although sometimes they can be locally common they are predators and tend to live in water bodies, like dams and lakes at densities that do not deplete prey numbers too much; once prey numbers get too low, these beetles fly to a new water body and establish themselves there.

Adults lay their eggs in the water where tiny predatory larvae hatch out. The larvae spend their entire larval stage in the water before digging into the muddy banks of ponds and pupating. Once mature, the adults can either hang out where they emerged or fly and disperse to other areas where the food source is more readily available.

Over the last 12 months in Victoria, like many parts of Australia, has had increased rainfall which allows the beetles to disperse and breed at a greater rate than over the last few years of drought. Live Exhibits staff are predicting a great summer for Green Diving Beetles and they may turn up a bit more often in the Melbourne metropolitan area. Live Exhibits staff will be heading out equipped with torches, nets and waders to see if we can hunt down these incredible animals.

Green Diving Beetles
Green Diving Beetles can be voracious feeders; here a group of them are feasting on a dead fish at the Melbourne Museum.
Image: Alan Henderson
Source: Museum Victoria
 

These beetles are active predators and scavengers and add a great degree of movement and colour to our Bugs Alive! display. As they forage they constantly return to the surface of the water to replenish their air supply which they hold under their elytra (wing covers). They eat other aquatic invertebrates and in the wild will sometimes attack vertebrates such as small fish and tadpoles.

Next time you are in Bugs Alive! check them out in the aquatic tank. They spend a fair bit of the day sitting motionless clinging onto foliage but once they get moving they can certainly swim fast.

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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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