Author: EcoEvo@TCD

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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

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“Toxic” nectar and pollen in an invasive plant species

For the longest time floral nectar was considered to be made of two components: simple sugars (such as sucrose, fructose and/or glucose) and water.  Research carried out in the past two decades however has repeatedly shown this paradigm to be incorrect.  As analytical techniques such as high resolution GC-MS and HPLC have become commonplace, the composition of floral nectar of hundreds of plant species has been investigated in detail. The findings of this research have revealed that floral nectar has a lot of components other than sugars; amino acids, lipids, proteins, and vitamins have been detected at low concentrations.  One surprising class of constituents of floral nectar has been found in plant species belonging to over 21 different families; plant secondary metabolites.  It is strange to see these secondary metabolites- compounds such as alkaloids, terpenes, and phenolics- in floral nectar because we normally associate them with defence of plants against herbivores.  They are often repellent to insect visitors and can potentially cause floral nectar to be unappealing to flower-visitors.  The paradoxical phenomenon has many potential adaptive and non-adaptive hypotheses (see Adler 2000 for an excellent review) and it’s a subject about which there has been some really exciting literature published lately.

At NERD club one of our discussions focused around this topic of “toxic nectar”.  I study the toxins found in the floral nectar of Rhododendron ponticum, a group of compounds called grayanotoxins.  R. ponticum is invasive in Ireland and I am particularly interested in the effects of these toxins on native Irish insects that may use this mass flowering resource in early spring.  Our discussion ranged from thinking about work done in other systems in which plant toxins might play an important role to considering trophic accumulation and mechanisms by which organisms deal with ingestion of toxins. I enjoyed the meeting immensely and it made me reflect upon how useful it is to discuss your research with as many people as possible.  The varying opinions and perspectives that colleagues form different departments can bring to the discussion are both insightful and inspirational.  We get so involved in our own research it is refreshing to hear these different perspectives, so thanks to everyone who could come along!

Author

Erin Jo Tiedeken: tiedekee[at]tcd.ie

Photo credit

Erin Jo Tiedeken

 

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Thinking small to think big

Charles Darwin Bacteria (Serratia marcescens), Nutrient Agar, Petri Dish

The concept of using bacteria and other microbes to test some of the big questions is creeping more and more into the world of ecology and evolution. Evolutionary biologists have been coming around to this idea for many years now (see Lenski’s experiment for a wonderful example of this) but the concept is still hard for most ecologists, particularly empirical ones to swallow. This is primarily a function of the microbial systems being thought of as ‘too simplistic’ and ‘unrealistic’ to apply to real world populations. In a review in 2009 Angus Buckling and colleagues very elegantly address the above charges and some of the other most frequently raised arguments against using bacterial microcosms.  My argument (and his!) essentially comes down to two things:

1. Ecologists are supposed to be devising models and experiments to understand the dynamics of real world populations and the consequences of anthropogenic impacts on the organisms that inhabit the planet and yet they are largely ignoring the biggest Kingdom of organisms-Bacteria!

2. While nobody is suggesting that what happens in a 200ml microcosm tube will perfectly mimic or predict the exact response of a 200acre coral reef, why can they not be used as models to help test some of the theories or predictions that might equally affect larger systems?

Microbial systems have very similar dynamics to most other empirical food webs, in particular aquatic ones with highly size-structured predator-prey interactions, social cooperation and complex community networks. The importance of bacteria and microbes in the environment and their role in disease is undeniable and widely recognised meaning that individually bacteria are some of the most well studied organisms out their in terms of their genetic information and growth patterns. This can be used to the advantage of ecologists and evolutionary biologists by isolating strains of particular interest and culturing them very easily in laboratory conditions over short time periods to yield potentially very powerful results when viewed at the population or community scale.

One of the big problems in the field of ecology is linking empirical and theoretical study results; they frequently disagree due to the time scales, interactions and networks involved. The problem is basically that, however good the theoretical model, it cannot encompass all of the complexities of a natural system, and, similarly, while the empirical studies are more difficult to rebuke for their lack of realism or complexity, it is often impossible to disentangle the many different interactions taking place to get to the root of the question. What is therefore needed is a means to bridge this gap and provide logistically feasible model systems for testing more generalized ecological and evolutionary theory. I think the microbial systems might be a partial solution to this problem, as well as being fascinating for their own sake they can really aid in the developing and testing the drivers and disentangling the complex interactions in ecological and evolutionary processes. What they lack in size they certainly make up for in potential!

Author

Deirdre McClean: mccleadm[at]tcd.ie

Photo credit

Zachary Copfer: http://sciencetothepowerofart.com/

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“See you later, pollinator”

Scientific conferences can be a great way of meeting people, getting and sharing new ideas, and networking with people from, often, all over the world. And they can be good fun too! On October 25th-28th several people in the School travelled to Norway for the annual conference held by the Scandinavian Association for Pollination Ecologists (SCAPE). This meeting is held for ecologists working with pollination, plant reproductive biology and other related fields and it attracts a small but expert crowd from Scandinavia, Europe, and sometimes even further afield (this year there were attendees from Brazil and Israel!). Continue reading ““See you later, pollinator””