Alice

DISPLAYING POSTS BY: Alice (3)

Alice

Alice is part of the Discovery Centre team and works across both centres at the Immigration and Melbourne Museums. She loves exploring behind the scenes and wishes that her house looked more like the Wild exhibition space.

Death by coitus

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by Alice
Publish date
14 April 2014
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The other week I attended Isabella Rossellini’s comic and educational monologue Green Porno, a fascinating lecture on the sexual escapades of the natural world. It really got me thinking about the various and bizarre methods of animal reproduction that I've encountered since commencing my role at the Discovery Centre. We see an intriguing array of specimens brought in to be identified and in some cases even added to the collection. Many of these animals would be well-deserving of a feature episode on Isabella’s show, but none have captivated my attention more than our recent acquisition of a male phascogale. 

Phascolgales belong to the same group of marsupials as the Tasmanian Devil and the quolls. But unlike their relatives they have managed to keep a very low profile. Considering that male phascogales live fast, die young, and have such a frantic sex life that it kills them, I was really surprised that the first time I became aware of this genus was through the arrival of a neatly wrapped frozen specimen.

  Mount of Phascogale tapoatafa, Brush-tailed Phascogale  Mount of Brush-tailed Phascogale
Image: Benjamin Healley
Source: Copyright Museum Victoria 2003
 

Phascogales are among a rare breed of mammals that practice suicidal reproduction, or semelparity, where one or both sexes die after a single episode of mating. This strategy is seen in some invertebrate and plant species, but is extremely rare in mammals, only occurring in a few marsupials native to Australia, South America and Papua New Guinea. In Australia the male Phascogale, Antechinus, Dasykaluta and Parantechinus are the only mammals where the males literally mate themselves to death.

Mating season for these dasyurid marsupials lasts only a few short weeks, during which promiscuous females and anxious males copulate for hours at a time (Antechinus have been known to go at it for up to 14 hours!). During this concentrated period of breeding the males’ levels of testosterone and stress hormones become so extreme that even their muscles start to break down to help fuel the act. The intensity of prolonged mating causes the males' bodily functions such as their immune system to shut down, exposing their exhausted bodies to infection, internal bleeding and disease shortly after. The males will not even get to see the fruits of their labour, as they all die before their young are born.

Phascogale tapoatafa: Brush-tailed Phascogale Brush-tailed Phascogale from J. Gould's Mammals of Australia, 1863, vol 1, pl 31
Image: Artist: John Gould; Lithographer: H.C. Richter
Source: Out of Copyright
 

So why do you think male phascogales have been programmed to pursue such a life ending labour of love?

The answer lies in their sperm. For phascogales sexual selection occurs after copulating, where the sperm compete inside the female for fertilisation. Rather than fighting to gain access to mate with a female, males need to put all of their energy into fertilising as many females with as much sperm as possible. This also explains the lengthy duration of the mating spree – the more time one male spends mating with a female, the less opportunity other males have at gaining access to her. Combine this with the promiscuous frenzy of their breeding period and many females may nurture offspring from multiple fathers. 

I can only imagine the field day that Isabella would have illuminating the fascinating science behind the phascogale's reproductive biology. A glimpse at any of her online videos will give you an idea.

Links:

Diana O. Fisher, Christopher R. Dickman, Menna E. Jones, and Simon P. Blomberg (2013) Sperm competition drives the evolution of suicidal reproduction in mammals Proceedings of the National Academy of Sciences, published ahead of print 7 October 2013: doi:10.1073/pnas.1310691110

Preparing to Think Ahead

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by Alice
Publish date
5 December 2013
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The whole preparation department have been hard at work over the past few months getting their creations ready for the opening of Scienceworks' new permanent exhibition, Think Ahead.

I went to visit the team during their last week of preparation to see some of their projects in the final stages of development.

Building model houses Building model houses
Image: Alice Gibbons
Source: Museum Victoria
 

What has always impressed me about all the clever individuals in the preparation department is that their job combines highly refined artistic skills with science and design....and a whole lot of patience and lateral thinking!   

The team’s recent body of work for Think Ahead is certainly a testament to their craft. Using a creative mix of materials ranging from state-of-the-art plastic technology to readymade dollhouse furniture, the team have created a wide range of objects and interactives for permanent display including plastic foods, futuristic human figurines, replica ice cores, miniature dioramas and life-sized human mannequins. They even utilised the museum’s 3D printer to produce miniature model tyres for their futuristic farm machinery.

3D printed tyres 3D printed tyres
Image: Alice Gibbons
Source: Museum Victoria
 

Future food Future food
Image: Alice Gibbons
Source: Museum Victoria
 

With the exhibition targeted at 8 to 12 year olds, the team have included many clever little twists to catch the eye of their audience. In one display, a model dolls house that shows the evolution of a child’s bedroom from the turn of the century to today, and references to contemporary pop culture are included in the form of mini Diablo and Angry Birds posters pasted on the walls of the modern bedroom. 

Bedroom diorama Bedroom diorama
Image: Alice Gibbons
Source: Museum Victoria
 

Other creations such as Michael Pennell’s future human figurines and Steven Sparrey’s silicone life sized mannequin (modelled from Michael's face) look like props right from the set of a new sci-fi blockbuster.

Future human figurines Future human figurines
Image: Alice Gibbons
Source: Museum Victoria
 

Think Ahead opens this week at Scienceworks.

Nature's nappies

Author
by Alice
Publish date
14 November 2013
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Here at the Melbourne Museum Discovery Centre we are inundated with a wide variety of interesting enquiries. We recently received this stunning photograph from a keen bird enthusiast in Camberwell, wondering what was being fed to the young chicks.

Wattlebird with faecal sac. Wattlebird with faecal sac.
Image: Jim Love
Source: Jim Love
 

Interestingly, the parent wattlebird pictured is not actually feeding this infant but cleaning up after it. 

The black and white material in the parent’s beak is what is called a faecal sac, a mucous membrane that contains the excrement and uric acid (the bird equivalent of urine) of the young nestling. The thick membranous exterior of the sac is strong enough for the parent to pick up with their sharp beak to carry away and dispose of without puncturing it. They are just like a disposable nappy for birds!

Faecal sacs are usually excreted by the chicks shortly after feeding takes place, but this varies from species to species. In the case of the wattlebird the production of a faecal sac is almost instantaneous after feeding. This immediate reaction ensures that whichever parent feeds the chicks, will also be there to carry away the waste at the same time. You can see this occurring in the image below, where the parent is extracting the sac from the nestling’s cloaca as it is being produced.

Wattlebird with faecal sac. Wattlebird with faecal sac.
Image: Jim Love
Source: Jim Love
 

Parents remove faecal sacs from the nest for a number of very important reasons.  Not only do they allow the nest to remain clean and hygienic for the young nestlings, but their removal also deflects the attention of predators by eliminating the scent and sight of the faecal matter. Different species dispose of their faecal sacs in different ways, some preferring to drop them into bodies of water to completely erase their scent while others simply drop them nearby.

Some species of birds will even eat the contents of their baby’s faecal sacs for the first couple of days after hatching. In very young nestlings the bacteria required to digest their food are still under development, hence their excrement is rich in partially digested food. This allows the parents to feed more worms and insects to their young as they can substitute their own meals for the nutrients in their baby’s droppings. 

Wattlebird with faecal sac. Wattlebird with faecal sac.
Image: Jim Love
Source: Jim Love
 

Not all species of birds produce faecal sacs. Young water birds such as ducklings and goslings leave their nests as soon as they hatch, often never returning, and therefore do not have to worry about continual housekeeping. While other birds including eagles, herons and some sea bird species that nest high in trees and on cliffs, will simply back up to the verge of their nests and excrete off the edge.

I will leave it to you to decide whether you think faecal sacs are disgusting, strange or just plain fascinating. Personally, I wish that all human babies were this easy to clean up after!

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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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