Month: November 2012

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War of the worms

A battlefield

Some of the most successful animals on earth live in societies characterised by a division of labour between reproducing and non-reproducing castes.  One role non-reproducing members may undertake is defence. Spectacular examples include the heavily armoured termites and ants. Recently a soldier caste was discovered in an entirely new and unexpected battleground, inside the bodies of snails. The soldiers? Tiny parasitic flatworms.

Flatworms, or trematodes, have complicated life cycles, involving several different stages infecting a variety of host species. In one host, often a snail, a single trematode undergoes repeated clonal reproduction. Clones produce more clones or go on to produce the next infective stage, which leaves the snail to infect the final host. While working with trematode colonies of Himasthla sp. infecting the Californian horn snail Cerithidea californica, researchers at the University California Santa Barbara observed that the trematode occurred in two distinct morphological forms. There was a large reproducing primary morph, which appeared to be the form typically described in the literature, and a secondary smaller, thinner morph.

These secondary morphs had a number of other features which set them apart. They rarely showed any signs of reproduction and were far more active. They also had huge muscular pharynxes and guts relative to their larger sisters. When researchers preformed behavioural tests, they discovered just what those large mouth parts were for. The secondary morphs attacked and killed other trematode species and unrelated conspecifics. This behaviour is not unknown in trematodes; a number of species attack and kill other trematodes. What was novel was that the smaller morphs appeared to be doing all attacking. The behaviour was rarely observed in the primary morphs. There was also a spatial segregation of morphs. Primary morphs were located in the visceral mass, mainly in the region of the gonads. The secondary morphs were more widely distributed though mainly found within the mantle. The snail mantle is the main entry point for trematodes, a strategic area to defend against invading armies. Finally, the researcher found very few intermediate morphs, suggesting that the smaller morphs were not simply juvenile stages of the primary morphs. They were a distinct, permanent caste whose function appeared to be defence – soldiers. The researchers had discovered eusociality in a completely new taxonomic group.  Previously, eusocial systems consisting of morphologically distinct, specialised reproductive and non-reproductive castes had only been recognised in insects, snapping shrimp, a sea anemone and mole rats. The researchers have already suggested a further five species of trematodes that may have soldier castes.

Work from New Zealand, published this year, on another species (Philophthalmus sp.) has expanded the list of trematodes with soldier castes. The authors also showed that interspecific competition has a heavy impact on colony numbers. This is just the sort of pressure that favours adaptive strategies to reduce competition, such as a permanent soldier caste. However, competition may not be the only selective pressure driving or maintaining caste differentiation in trematodes. In the absence of competition, the presence non-reproducing morphs were found to provide a benefit to the colony, as measured by the number of infective stages produced. Precisely how this benefit comes about is not yet known. The authors suggest some form of communication or nutrient exchange may be taking place between the two morphs. This gives tantalising hints that these colonies are even more complex and interactive than previously thought.

Not only has the discovery of the eusociality in trematodes widened the taxonomic range of this phenomenon, it has also provided researchers with an exciting new tool to study its evolution. The Trematoda class contains at least 20, 000 species with a wide variety of life-histories and ecologies. The discovery is also a great example of how new and unexpected results can still come from well-studied animals. The Himasthla sp. /Californian horn snail system had been studied for over 65 years.

Author

Karen Loxton: loxtonk[at]tcd.ie

Photo credits

wikimedia commons

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The language of evolution on trial

Humans are purpose seeking beings. Such a fact is nowhere more apparent than in our language. Some scientists argue that this tendency is a cause of confusion in their subject, especially when it comes to descriptions of evolution. The teleological turn of phrase is so tempting because of how much easier it is to read and understand than a dry purposeless, but more accurate, expression.  ‘Wings evolved for flight’ isn’t quite right but we understand the message. I remember my chemistry teacher’s classes were replete with teleology, ions wanted to gain or lose electrons so they could balance their charge. But of course, none of us believed for a second that the atoms intended to do this. All there was to it were the blind forces of the atomic world. So it goes for evolution as our current understanding of the process is teleology free.

Richard Dawkins, who was put on this Earth to popularize evolution, is always quick to correct himself when his tongue slips to purpose. But I would argue that our linguistic short-cuts are not the primary cause of the public misunderstanding of evolution. It was Eugenie Scott who said for many people the problem behind evolution is not one of confusion, rather it’s a full understanding and disgust at the implications of it. Some of us don’t like the idea of being a ‘mere’ animal. Of course language matters but it would be a shame for us to avoid using language which can convey an idea so succinctly when it’s not to blame. Perhaps I’m being overly naïve here and we’re adding to the confusion with our lack of precision. So I’m open to debate on this one. What do you think?

Author

Adam Kane: kanead[at]tcd.ie

Photo credit

wikimedia commons

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How to save time with twitter

I was recently asked to write a blog post for SpotOn (Science policy outreach and tools Online) and thought I’d share a modified version of it here. If you’ve never heard of it, SpotOn is a series of community events hosted by Nature Publishing Group for the discussion of how science is carried out and communicated online. There are loads of excellent resources on the website which I’d urge you to check out if you’re at all interested in using the internet more in academia. I will probably write more blog posts about this in the next few weeks. Anway, here’s my post:

SpotOn London 2012: How to save time with twitter

Productivity gurus suggest that when faced with a list of tasks you should divide them into urgent and non-urgent, and important and unimportant tasks. Important urgent tasks should be prioritised; non-urgent unimportant tasks should sink to the bottom of the pile. Defining what is urgent is one thing, but defining what is important is quite another! Certain things are clearly important. But what about online activity such as writing blog posts or using twitter? Is that important?

Until recently I would have said no, but in August I decided to sign up to twitter (prompted by an excellent article in the BES magazine by @Philip_A_Martin). At first I felt I was getting very little out of the experience, except finding yet another way to waste my increasingly precious time. But then I realized the time I was spending on twitter was one of the highlights of my day. I was finding out about new research, gaining teaching materials, discussing science and networking with people across the globe. All in my pyjamas while drinking my morning cup of tea! This has led me to believe that almost every part of life as an academic can be enhanced by using twitter and, perhaps more importantly, that using twitter can save time in the long run. This may seem like a rather grandiose claim but I’ll try and convince you!

Networking and promoting your science

Perhaps the most obvious use of twitter is to promote your science and to network with distant colleagues -@mickresearch really impressed upon me the benefits of being able to have a global network of colleagues without having to spend time (or increase your carbon footprint) travelling. I’ve also seen examples of research collaborations started by discussions on twitter and, as many people have pointed out, it’s easier to network at conferences if you’ve already interacted with someone online. Thus twitter allows you to use your limited time at conferences much more efficiently. Twitter is also an effective way of promoting your papers without the need to write a long press release – 140 characters and a link to the webpage and you’re done!

Teaching

I rarely have time to trawl the literature for new and exciting examples to engage my students and keep my lectures up to date, but with twitter I don’t have to. My twitter feed is full of interesting new papers, blog posts, photos of crazy creatures and titbits of information that help me liven up my lectures. And I’m only minimally using twitter’s capacity to enhance teaching. Teaching through twitter is also an option: recently @Drew_Lab gave a lecture to students via twitter because they couldn’t make it to class after hurricane Sandy. The students were able to ask questions and have discussions, and people outside the class also joined in (although @Drew_Lab did briefly end up in twitter jail in the process!). This could be a wonderful way of supporting flexible working practices.

PhD student supervision

In our school, students are expected to complete their PhDs in 3 years, so efficient supervision is critical. However, I don’t have the time to teach them everything they need to know in a timely fashion. Currently my focus is on helping them to plan their projects but they also need training in data management before they start generating data. Luckily twitter saved the day again with some excellent slides and a help document on data management from @carlystrasser. This saved me time now, and possibly countless hours in the future as I won’t need to help them sort out badly organized data when they get to their analyses.

Research

Another thing I rarely have time for these days is reading research papers. There are so many that it’s hard to even find time to read all the abstracts, let alone get any idea of the methods employed. Again twitter helps. People post information on new papers they’ve read and found interesting; they post links to blogs about papers that are much quicker and easier to read than the full paper. There are also lots of posts about new methods, R packages, statistical issues and new datasets. Knowing the up-to-date consensus on analytical methods can save lots of time dealing with referee’s comments in the future! Using twitter gives me a little time each day to think about these kinds of things, and to consider new avenues of research. Without this opportunity I could go for weeks thinking about nothing other than my next lecture!

Science policy

@AtheneDonald recently pointed out the large number of science policy makers found on twitter. Science policy, whether it be promoting women in science, the proposed badger cull, or changes in the kinds of research funding bodies will support, is really important to all of us. But finding time to process all of this information is impossible. Twitter gives me a quick digest of the major issues, and alerts me to things that I will need to act on in the future.

Sense of community

Finally, I think this is the nicest, and perhaps most often overlooked, aspect of twitter: the sense of community. It’s far too easy to feel overwhelmed by the extreme pressure of academia, no matter what level you’re at, and to feel as if you’re the only one who isn’t coping. This may go some way to explaining the “leaky pipeline” for female scientists. So it’s reassuring to see other academics tweeting about the stress they are under balancing work and home life, or their difficulties in writing grants, getting papers published or finding a job. It’s also wonderful to see people supporting one another through these crises. I think this aspect is particularly important for women, parents with young children and people with flexible working hours, who may lack the support network they need in their own institutions.

In conclusion, I think the benefits of twitter go far beyond those of promoting yourself online. Although it takes time, if you can manage that time into sensible short blocks I think you can save yourself time in the long run. And if you’re a busy junior faculty member like me (or a busy senior faculty member for that matter), being able to discuss research on twitter can remind you why you got into academia in the first place!

Author

Natalie Cooper: ncooper@tcd.ie

@nhcooper123

Photo credit

wikimedia commons

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A Waxwing winter you say?

The Bohemian Waxwing Bombycilla garrulus might not be a bird you are too familiar with, but this winter might change all that, for it seems we’re heading for a Waxwing winter. Don’t worry; Waxwings are not giant, flesh-eating birds. They are, in fact, a small and very beautiful passerine species that migrate to our lands to feast on fruiting bushes and trees.

The breeding range of the Bohemian Waxwing extends across most of northern Europe, Asia and western North America, and our nearest breeding populations are to be found in northern Sweden and Finland. These exotic-looking birds visit us each winter in small numbers but some years, known as irruption years, when the resources available at their breeding grounds are not enough to meet the demands of the population, there are huge migratory influxes into Ireland and Britain. One such cause of these irruption years is a failure of the berry crop and this is said to have happened across Scandinavia this year.

These birds typically arrive on the north and east coasts and make their way inland as they gorge on our rowan, hawthorn, rose hip and cotoneaster berries. Waxings tend to frequent urban areas as rowan and other trees line many of our gardens, streets and car parks (so next time you’re out shopping stop, listen and have a wee look around). I’ve heard from numerous people this year that the berry crop in Ireland has been very poor and this could spell bad news for the Waxwings. On top of this, we receive huge influxes of winter thrushes such as Redwing, Fieldfare and continental Blackbirds which are also berry fans, making for stiff competition.

So what then for the Waxwings? It seems likely they will keep pushing further west and south in search of more food – some have already shown up in Kerry, Cornwall and the Isles of Scilly! It will be exciting to see reports next year from monitoring programmes such as BirdTrack as to how far south, and in what numbers, the Waxwings were forced to migrate in search of food. You can take part in reporting them too. It will also be very interesting to see how their populations fare over the winter, especially if it’s a severe one. Let’s hope they fare well.

Author

Sean Kelly: kellys17[at]tcd.ie

Photo credit

wikimedia commons

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Tenrec tales

Tenrecs are one of the most interesting and fascinating mammal groups yet many people have never heard of them. They are one of only four mammalian groups to have colonised Madagascar, a land filled with evolutionary curiosities.

Tenrecs are a striking example of convergent evolution. From a single colonising ancestor, tenrecs have evolved into incredibly diverse species which resemble moles, shrews, hedgehogs and even otters! Contrary to appearances, tenrecs’ closest relatives are actually the golden moles and elephant shrews (Chrysochloridae). However, physical convergences are so strong that early taxonomists didn’t recognise tenrecs as being closely related to each other, an easy mistake to make when you look at this picture from Richard Dawkin’s 1996 book “Climbing Mount Improbable”.

Convergent evolution in tenrecs. The Algerian hedgehog, Erinaceus algirus (a), is a close cousin of the shrew hedgehog, Neotetracus sinensis (b). The greater hedgehog tenrec, Setifer setosus (c), is a close cousin of the long-tailed tenrec, Microgale melanorrhachis (d)

In addition to being great species for studying convergent evolution, the tenrec family includes a whole host of quirky traits. For example, the common tenrec (Tenrec ecaudatus), an animal which is only around 30 cm and 2kg, holds the record for the largest litter size of any mammal at an astounding 32 babies!

My personal favourite tenrec oddity is the unusual means of communication found in the lowland streaked tenrecs (Hemicentetes semispinosus).  These cute critters are covered in spiny quills, a special set of which are used as a stridulating organ. Reminiscent of grasshoppers or crickets and uniquely among mammals, these tenrecs rub the quills together to produce sound which then allows them to keep in contact with their family group. This clip from the David Attenborough BBC series on Madagascar shows the stridulating tenrecs in action.

In short, tenrecs are an awesome family filled with evolutionary oddities yet they remain relatively understudied and poorly understood.

In my PhD work, I’m particularly interested in measuring the extent of convergent evolution in tenrecs and figuring out the reasons why they have evolved to be so similar to unrelated species. I’m also intrigued by early behavioural experiments which showed that 3 species of tenrec use echolocation. I want to test whether other tenrec species also echolocate and hopefully link this behavioural convergence to genetic similarities in “echolocating genes” which are conserved in whales and bats.

In the meantime, a charming children’s book gives the perfect excuse for some light, PhD-related extra reading!

Author

Sive Finlay: sfinlay[at]tcd.ie

Photo credits

wikimedia commons

Richard Dawkins

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Academic heroes

Most people have heroes. As this is a science blog I’m guessing you are already battling out Captain Kirk vs Spock, Batman vs Spiderman or Inspector Gadget vs MacGyver, in your head in order to choose the most appropriate hero. But here, I mean academic hero. That person whose work becomes the foundation of our academic thinking or that we simply admire for their lifetime academic achievements. Deciding on our academic hero makes a great conversation topic and it usually ends up covering pretty much the whole history of science. In my lab, there is an ongoing interest for academic heroes. Some of us would even secretly (or not) like to have a bobble head of our academic hero.

As I work in a mostly theoretical lab whose research is pretty broad, ranging from fisheries, to social evolution and behaviour (some lab members, when asked, simply reply “ecology”), it is not surprising that our academic heroes are not the same person. Even agreeing on what could constitute one, is sometimes controversial. Some scientists just have to be heroes, for example Darwin would be in most academic’s top five for his theory on natural selection, and so would Watson and Crick for the discovery of the DNA double helix that changed the way we do science. But few people would contest their achievements are worthy of the academic hero title and consequently not much fun for a bobble head. Others, in fact most, are surrounded with pro and con arguments and we must be passionate enough to defend them (as we would for Spock). For example, Richard Dawkins is a name that pops up in the blogosphere quite often as an academic hero, not because of his forefront ideas but for popularizing evolution, a hot topic among the public. Should he be a contender for academic hero? Surely Carl Sagan who made cosmology popular is.

My academic hero, which I shall not name as I might meet him someday and I don’t want to appear a ‘fangirl’ (which I am but doesn’t sound very professional…), amazes me for the numerous ideas and frameworks he put forward in many different subfields. Those ideas and frameworks are perhaps not recognized as important as DNA or natural selection, and many have been rebutted already. However, without them, the progress in ecology and evolution would have been much slower and would likely have taken a different route, i.e. he shaped the field. In my view, he is definitely bobble head material! I’m generally a shy person and a few years ago I missed the opportunity to meet my academic hero in a conference to shyness. How do we go about introducing ourselves to our heroes? Imagine going to Batman and saying “Hello, I LOVE the way you save the world, could you sign my bat-shirt please?”

We always read about tales of people meeting their heroes and generally something embarrassing happens… have you met you academic hero? Tell us your tale.

Author

Mafalda Viana: vianam[at]tcd.ie

Photo credit

wikimedia commons

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Cod, correlation and causation

so help you Cod

 at the Guardian reports on a battle between science and politics which is worth highlighting. The Atlantic cod fisheries in the Atlantic collapsed during the 90s due to overfishing. They have yet to recover. The Atlantic cod is an apex predator and its decline effected a trophic cascade, which modified the original food web, perhaps irrevocably.

The Canadian government is holding the grey seal responsible for this. They argue that the seals, which are growing in number, are preventing the recovery of the stocks and are planning to kill 70,000 of them next year.

This has vexed a group of marine biologists at Dalhousie University so much that they wrote an open letter arguing that cod are rarely preyed upon by the seals. Instead, the cod’s main predators are other, larger fishes. And in actual fact, the seal preferentially feeds on these fishes. So any reduction in seal numbers will produce the opposite result to the one intended, seals will be killed, the predatory fish population will increase, and the cod population will decline even further.

Correlation does not imply causation. But perhaps, the view of the Canadian government is that of Winston Churchill who once remarked, scientists should be on tap, not on top.  It will be interesting to see how this one plays out.

Author

Adam Kane: kanead[at]tcd.ie

Photo credit

wikimedia commons

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Bamboo systematics: less swaying in the wind

Young shoots of Phuphanochloa Sungkaew & Teerawat.: a new species and genus of woody bamboo discovered by TCD botanists.

The bamboos are an extraordinary group of plants and the only large group of grasses to diversify in forests. They represent a major radiation in the angiosperms with nearly 1,500 species. The Bamboo Phylogeny Working Group (including TCD botanists Sarawood Sungkaew and Trevor Hodkinson) have recently used molecular, anatomical and morphological characters to update the tribal and subtribal classification of bamboos including the new genus (Phuphanochloa) shown in the photo.

Authors

Sarawood Sungkaew

Trevor Hodkinson: hodkinst[at]tcd.ie

Photo credit

Trevor Hodkinson

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A dose of Darwin

One of the more irksome aspects of life is getting sick, I always think we should be beyond this. When it comes to medicine I suppose we can ourselves lucky to be alive at a time when doctors and butchers are no longer interchangeable. But even in the 21st century we’re still engaged in arms races with bacteria and chemical warfare with cancer (military metaphors are never in short supply) . Bacteria evolve resistant strains to our best antibiotics and tumours do likewise against our attempted cures. Less grave but still illustrative is the perennial persistence of the common cold. Illness comes in many forms, wellness only one. The main problems we face in trying to create cures is that all pathogens are evolving and to realise that we too have evolved. We often end up using static measures against dynamic problems.

That said, I think this century will see some considerable advances in medicine owing to the increasing use of evolutionary insights to combat disease. This is the science of evolutionary medicine.

Some of the symptoms we most associate with being sick like fever, pain, nausea and vomiting aren’t from the disease per se, but the body’s defences in action. Randolph Nesse, who wrote the book on evolutionary medicine, says that medical doctors would do well to recognise our evolutionary origins when treating their patients.

Our biology is playing catch up to our cultural advances and this lag period can explain many modern afflictions. Nobody reading this suffers from prolonged periods of hunger but we still stuff our faces when we get the chance. Of course, before modern civilization our next meal wasn’t always a sure thing, so gorging when the going is good was the way to go. The upshot of this is a significant proportion of the developed world is obese.

Some of the ideas of evolutionary medicine seem to run counter to our regular approach and our intuition. For instance, when treating a patient with chemotherapy, we use the most potent chemicals and this seems perfectly reasonable. We want to hit the tumour hard and fast. In fact, all we do then is put a strong selective pressure on the tumour cells to evolve resistance, ultimately shortening the patients’ lives. Instead, we should only give the minimum dose necessary to keep the cancer under control.

Fleming’s discovery of penicillin is one of those instances of serendipity that turned out to be a great boon for medicine. But I’d prefer not to rely on serendipity if you don’t mind! It would be far preferable to know why how and why diseases arise. Bernard Crespi is doing this with his research on schizophrenia and autism. Crespi argues that these disorders are diametrically opposed, autism is the result of an underdeveloped social brain whereas schizophrenia comes from a hyper-developed one. They are caused by the abnormal expression of imprinted genes, i.e. ones expressed according to the parent they came from. If true, then we can use opposing treatments to treat these twinned disorders.

Unfortunately, as Richard Dawkins puts it, we evolved to be fecund not necessarily to be healthy. Any competition between the two and the latter won out. But now at least we know that’s the case and we can do something about it.

Author

Adam Kane: kanead[at]tcd.ie

Photo credit

Dr. Barbara Natterson-Horowitz

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Biodiversity in Our Lives

It’s worthwhile highlighting the recent success of the “Biodiversity in Our Lives” campaign which has generated some notable publicity this week in Science. PhD students here at Trinity College decided to impress upon the public some facts about biodiversity and how it can impact our lives, often in surprising ways. To do this they decided to create a series of beermats which have succinct descriptions of these impacts. Pubs around Dublin have received a second round of the beermats and to coincide with this many of the students are giving pop up pub talks.

Author

Adam Kane: kanead[at]tcd.ie

Photo credit

Biodiversity in Our Lives