The Best Australian Science Writing 2012

by Elizabeth Finkel

  It is estimated that only around 40 per cent of cockroach species can fly, for instance, and most are rather inept at it. They cannot fly very far. As for the notion that cockroaches would survive a nuclear apocalypse, think again: they are not especially tough.

  A dose of radiation as low as 64 grays kills 93 per cent of immature German cockroaches. Sure, that is ten times as much as humans can take, but cockroaches do not look so tough compared with the humble fruit fly, which can survive exposure to more than 640 grays, or the parasitoid wasp, Habrobracon, which needs a colossal 1800 grays to kill it.

  Continuing my search, I discover that cockroaches thrived long before there were kitchens. They are one of only a handful of insect orders whose fossil record goes back more than 300 million years. Their heyday was during the Carboniferous period, when around 40 per cent of all insects were roach-like, prompting some palaeontologists to describe this period as the Age of the Cockroach. Before turning to beetles, it seems that evolution once had an inordinate fondness for cockroaches.

  These ancient ‘roachoids’ were not that different from modern roaches. Females had a long ovipositor for laying eggs – it disappeared around 140 million years ago – but otherwise they all look pretty similar to my kitchen guests.

  Nowadays there are nearly 5000 species of cockroach and they live on every continent except Antarctica, finding homes in caves, woodlands and rainforests. Only a handful of species have adapted to living with humans, but it is these that have spread all around the world. ‘They give the rest a bad name,’ says entomologist Nathan Lo at the University of Sydney. ‘While I am repulsed by the pests, not all cockroaches are nasty; some are quite beautiful.’ Really?

  Two of the most infamous pests are the large American cockroach and the smaller German cockroach. Their names are misleading, as it is not clear where they originated, nor when they spread around the world. It is the German variety, I learn, that infests my kitchen.

  Which brings me back to my question: why have these critters been so successful? Martyn Robinson, an entomologist at the Australian Museum, thinks it is partly to do with their lack of specialised features. ‘Cockroaches have specialised in not specialising,’ he says. In particular, most roaches are not fussy eaters. ‘Roaches are masters of cannibalism,’ Lo says. ‘They’ll eat everything and they’ll eat each other.’

  Sometimes they even eat us. There are many accounts of people sleeping in heavily infested buildings or ships being bitten by cockroaches. The varmints seem to have a special liking for calluses and nails, perhaps because they can nibble them without waking their victims. Sailors on some ships reportedly wore gloves while sleeping to protect their fingernails.

  There is, however, something else special about cockroaches besides not specialising. When a cockroach is opened up – or even just squished – you can see a white mass that fills much of its abdomen. Known as the fat body, this consists of two types of cells: adipocytes, which are filled with fat globules, and mycetocytes, packed with bacteria.

  Around a fifth of insects harbour mutualistic bacteria and some have mycetocytes similar to those of cockroaches. But the relationship between a cockroach and its resident endosymbiont, called Blattabacterium, is especially close. Kill the bacteria with antibiotics, and the roaches struggle to survive and often die. Kill the cockroaches and Blattabacterium definitely dies. While some insects acquire mutualistic bacteria from the environment, every cockroach hatches with Blattabacterium already inside it. When the eggs are developing, a few bacteria somehow move from the fat body to the ovaries, where they are taken up by every egg.

  Last year, Zakee Sabree of the University of Arizona compared the genomes of bacterial strains living inside the American and German cockroach. He showed that the two strains diverged at least 140 million years ago – around the time the fossil record showed that the two cockroach lineages themselves split. Since they went their separate ways, neither bacterial lineage has changed much.

  Lo thinks the relation between the ancestors of cockroaches and of Blattabacterium was so successful that there has been no need for the bacterium to change. ‘Once they developed a relationship, bam! They were able to dominate,’ says Lo.

  Even before Sabree’s study, Blattabacterium had come to be seen as a defining feature of cockroaches. When it was found inside the Australian termite Mastotermes darwiniensis, it made people wonder whether termites were related to cockroaches. Sure enough, a genetic analysis by Lo in 2000 confirmed that termites are the descendants of a wood-eating cockroach. ‘At the time it was a little controversial, but now we know the termite is definitely a type of cockroach,’ says Lo.

  But what does Blattabacterium do? Most mutualistic bacteria in insects provide them with nutrients that they do not get in their diet and cannot make for themselves. The location of the bacteria provides another clue.

  Nitrogen is a key component of amino acids, the building blocks of proteins, but animals usually excrete any excess nitrogen in the form of ammonia, urea or uric acid. By contrast, when cockroaches consume more nitrogen than they need, they store the excess in the fat cells of fat bodies, in the form of uric acid crystals. ‘Even when fed really high-nitrogen diets, they still don’t void the excess nitrogen,’ Lo says.

  So it has long been suspected that Blattabacterium might help cockroaches recycle nitrogen. No one was able to prove it, though, because the bacterium will not grow outside roach cells. But nowadays there is a new way to find out what bacteria do: sequence their genome.

  Even that is easier said than done. Just getting a pure sample of Blattabacterium DNA is tough. The cells containing the bacteria are sandwiched between fat cells, making it impossible to manually extract them. Plus, once the cells are collected, the bacteria have to be separated from the organelles inside the cell. Lo and his colleagues finally managed to isolate the bacterial DNA in 2008. Finally, it was time to sequence the genome.

  But Sabree beat him to the punch. In 2009, his team published Blattabacterium’s genome. The genomic analysis confirmed that the bacteria have all the enzymes needed to convert urea and ammonia into all ten essential amino acids. They can also produce several vitamins.

  So the fat bodies not only provide a store of fat that enables many cockroach species to go for more than a month without food; they also allow it to survive on very poor, low-protein diets. ‘It has its own chef and refrigerator on its back,’ says Sabree.

  The partnership between the cockroaches and their mutualistic bacteria may well have been the key to their success over the past few hundred million years. Despite their dietary superpower, though, only a few cockroach species had all it takes to conquer human habitations. Entomologist David Rentz has counted no fewer than 84 species of cockroaches around his home in the rainforests of northern Queensland. Yet only the German and American roaches actually live and breed in the house.

  The species that have switched to living in human homes are not only able to eat just about anything – they are also able to go for long periods with little water. ‘Some other cockroaches come in at night when the lights are off,’ Rentz says, ‘but usually you find them dead on the floor, because they get dehydrated [in the house].’

  The bad news is that the invasion of our homes is not over – there might be roach reinforcements on the way. One cockroach native to Australia, Methana marginalis, has started turning up in houses around the country in the last few years. It’s unclear whether it has evolved the ability to breed inside houses yet. Having never found nymphs around his house, Rentz suspects not.

  Recently, though, I have started spotting more and more of these native critters, with their light brown stripes, around my place. Lo thinks they are beautiful and wouldn’t mind them walking up and down his arm, ‘unlike those filthy Americans’.

  I have to agree, they are daintier than the American or German pests. But if I ever catch them fornicating in my kitchen, it’s the old milk-carton treatment for them too.

  Uninvited guests<
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  Procreation

  Ancient life

  Australia in 2050

  Julian Cribb

  Welcome to 2050, ladies, gentlemen and children. You’ll notice a few changes in how we Australians do things, compared with the turn of the century – all for the better, once we had shed the anxieties that were holding us back. Please accompany me on this brief tour of the new Terra Australis.

  First, let’s have a look at what’s driving the economy. Our biggest export, far and away, is knowledge (including technology and advice). And our biggest export sector is climate adaptation: from food production, to water management, to construction of homes and workplaces, urban design and tropical medicine, we used our own natural climate volatility – droughts and flooding rains – as an intellectual springboard for creating a host of new industries able to thrive in the rougher, mid-century conditions. Their products are now in huge demand worldwide.

  Our second largest export is energy. This was achieved through the construction of the Energy Superhighway (ESH), an ultra low-loss DC transmission link that originally extended from southeastern to northwestern Australia, enabling diverse sources of clean energy to compete for a global market. Today the ESH radiates across the industrial heartland of Asia itself, as far as northern China, exporting Australian clean energy from solar thermal, hot rock geothermal, integrated gasification combined cycle (clean coal), thorium (safe nuclear), marine and other power facilities, to regions which need it. Three-quarters of the photons (from sunlight) harvested in central Australia end up powering factories and cities in Asia.

  Our third contribution, and perhaps our greatest so far as human civilisation is concerned, is sustainable, healthy food. From eating a few dozen plants in 2011, Australians now consume several thousand (including many native plants) in a far healthier diet that has reduced by almost half the number of premature deaths attributable to diet-related diseases, the main killer at the start of the century. Our chefs and restaurateurs are acknowledged leaders of the global trend in sustainable, healthy, delicious eating.

  Furthermore we have ‘greened’ our great cities so they continually recycle both nutrients and water into the food system, safely and healthily. On roofs, sides of buildings, and open spaces, food plants flourish.

  We manage our livestock – mainly cattle, sheep, kangaroos and fish – remotely using electronics and telemetry, achieving clean, sustainable and balanced protein production, even in the deep oceans.

  Transport ‘fuel’ has changed dramatically, with solar-hydrogen providing the principal power for long-distance and heavy haulage, biodiesel for farms and remote areas, and mains electricity for urban and personal transport. The solar windjammer has staged a comeback, and Qantas flies on bio-jet fuel produced on large algae farms, fed by society’s organic wastes.

  Mining is almost entirely robotic and ‘keyhole’, leaving a minimal footprint. Following the ‘landfill rush’ of the 2030s, there is a strong focus on mining urban waste streams and recycling metals.

  One of the main changes you will notice in the new Australia is in defence. After a succession of Asian wars that gained us little more than resentment, we shed our posture of reliance on others’ military empires in favour of an independent stance, akin to that of Sweden, Switzerland and New Zealand.

  In a world roiled by conflict, and mass migration driven by escalating climate impacts and competition for scarce resources, instead of spending its sons and daughters in other people’s wars, Australia’s ‘forward defence’ philosophy has led us to intervene early by providing the food, water, energy and environmental systems that help to stabilise conflicted and stressed regions. This reduces the risks of social collapse, war and resulting refugee tsunamis. As in healthcare, the principal focus is now on prevention rather than ‘cure’. And the principal yield is friendship and economic opportunity.

  * * * * *

  Back in 2011, the arts, the humanities and culture were the poor cousins of Australian industrial aspiration. Today, the ‘creative economy’ is our largest employer by far. From music to food to fashion and art in all its forms, Australian culture has truly flowered.

  We have literature, history, holographic theatre, opera, sport in endless diversity, and ‘fusion art’, where teams of creators labour in cyberspace to build utterly new experiences. With most of the ‘dirty work’ of society now performed by automata, the opportunity has emerged to give free rein to the creative instincts of all individuals – almost everyone tries to devote a few hours a day to creating something unique and valuable in this new ‘Athens of the South’.

  A shining light in this evolution has been the renaissance of Aboriginal culture and ecological wisdom, which has served as a beacon both for the creative sector and for the sustainable management of Australian landscapes and waters.

  Biomedicine has long been a focus of Australian achievement, but in recent decades, with every individual’s genome available at birth, the accent has been on preventive healthcare through life – awareness of one’s own vulnerabilities and guidance in developing a life-plan to minimise them.

  Healthcare (and healthy eating) are now woven through all subjects in the curriculum. Every school teaches children how to grow food – and to respect it with the environment that produces it.

  New farming systems have greatly reduced the terrestrial footprint of agriculture, enabling large segments of the landscape to be restored to ‘Australian’ condition. Most endangered species are now much more secure, and several – like the thylacine – have been resurrected from remnant genetic material.

  Most farms now incorporate a significant percentage of native crops in systems designed to be both climate-proof and productive of healthy foods. The war on invasive species, however, continues, aided by continent-wide networks of monitors.

  Disturbed at the ability of the new quantum computers to store and regurgitate even the tiniest details of an individual’s entire life, deeds and words, and the scope for misapplication of this by corporations and the state, Australia is a leader in worldwide efforts to preserve individual liberties in the face of growing global pressures for social control, as the human population continues to swell.

  Indeed, individual freedom remains one of the greatest keys to the Australian character, creativity and enterprise.

  * * * * *

  Finally, the Reserve Bank is no longer the power it used to be for regulating the economy. The source of all the action in 2050 is the Knowledge Bank, established in the 2020s to provide that most precious of human attributes – knowledge – to every citizen for free. This led to radical advances in education, with people working together online in communities of interest or profession, to learn, study and share new understandings and skills.

  There are, of course, many other features of Terra Australis 2050 which I’d like to share with you – these are just some highlights. At the turn of the century, of course, many people said it could not be done, that it would cost too much money, that it involved too great a change. In the upshot, we know that none of that is true.

  Just as the car replaced the horse, the plane replaced the train and vaccines replaced the herbal remedy, Australians, as a diverse and enterprising people, were able to seize and develop the new opportunities of the 21st century as they emerged. The grounds for every single one of them were already laid in 2011 – all that was wanting was the courage, the vision and the investment to achieve them.

  Future gazing

  Big ideas

  Doctor’s orders:

  Debunking homeopathy once and for all

  Ian Musgrave

  Homeopathy’s got a bit of a run in the media in recent months and the stories are by no means positive.

  It all started in April when the medical press highlighted the National Health and Medical Research Council’s (NHMRC’s) impending statement on the practice.

  ABC television’s Australian Story then broadcast ‘Desperate Remedies’, bringing the non-medical
base of homeopathy into the spotlight by telling the tragic tale of actress and model Penelope Dingle. And then the commercial stations jumped on the bandwagon with Channel 7’s Today Tonight running a story about homeopathy.

  The NHMRC is still finalising its statement, which, it says, is based on one by the UK House of Commons Science and Technology Committee. It has also said it will likely recommend to insurers that they not pay for homeopathy because studies have found it to be ineffective.

  * * * * *

  Homeopathy is a system of healthcare based on the idea that ‘like cures like’ – substances that cause the same symptoms as an illness can cure that illness, and the idea that extremely small dilutions, so small that there’s almost no chance of the original substance being present, are more effective than more concentrated solutions.

  If the former sounds a bit like alchemy, that’s because it is. ‘Like cures like’ is a fundamental principle of medical alchemy, endorsed by no less than the father of pharmacology, Paracelsus. Homeopathy reflects this idea because when its founder, Samuel Hahnemann, first formulated his approach in 1796, alchemy was on the wane but still influential. Medicine then looked nothing like it does today, with extreme treatments like bleeding, purgatives and heroic concentrations of opiates in common use.

  Using fruit juice to combat scurvy would only be widely implemented in five years’ time; vaccination lay six years in the future; and the germ theory of disease lay over 50 years in the future. So did the Law of Mass Action, which states that in chemical reactions, the fewer the atoms, the less that happens (clearly a law that homeopathy violates). So it’s not surprising that homeopathy became popular: in an era where conventional treatment was just as likely to kill you as cure you, the gentler ultra-dilute tonics of homeopathy would at the very least not harm you. Medicine evolved as we came to better understand the body and developed effective medicines. But homeopathy didn’t. It remained mired in the same 18th century alchemical thinking. The homeopathic hospitals of the 19th century either closed or were converted – the former Prince Henry’s Hospital in Melbourne, where I used to work, started life as a homeopathic hospital.