Seminar series highlights: Phil Stevenson

hoenybee

As mentioned previously on the blog, Andrew Jackson and I started a new module this year called “Research Comprehension”. The module revolves around our Evolutionary Biology and Ecology seminar series and the continuous assessment for the module is in the form of blog posts discussing these seminars. We posted a selection of these earlier in the term, but now that the students have had their final degree marks we wanted to post the blogs with the best marks. This means there are more blog posts for some seminars than for others, though we’ve avoided reposting anything we’ve posted previously. We hope you enjoy reading them, and of course congratulations to all the students of the class of 2014! – Natalie

Here’s articles from Maura Judge and Chris Parsisson inspired by Professor Phil Stevenson‘s seminar, “Pollinator fidelity in coffee and citrus: is it all just sex and drugs?”

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An unlikely love story

Maura Judge

This is the story of a certain love affair, commonly known as floral constancy. The story involves pollinators and flowers. Floral constancy is the tendency of a pollinator to remain faithful to and exclusively visit a certain flower species or morphospecies. Whilst remaining faithful, the pollinator bypasses other available flower species that could potentially be more rewarding.

So what are the drivers of this phenomenon? For the plant species, the benefits are more obvious as pollinators that are flower faithful are more likely to transfer pollen to other flowers of the same species and hence, flower constancy favors flower pollination. Furthermore, flower constancy prevents the loss of pollen during interspecific flights and prevents pollinators from clogging stigmas with the pollen of other flower species. Hence, the reasons for the evolution of floral constancy in plants are obvious.

However, what could be the benefits for a pollinator? To ignore other flowers that could potentially provide more nectar than their preferred type contradicts the optimal foraging theory. Nonetheless, floral constancy has been observed in honeybees (Apis mellifera), bumblebees (Bombus terrestris) and butterflies (Thymelicus flavus). Drivers of floral constancy are rewards associated with cues such as flower shape, colour or scent. For example, honeybees have been found not to attempt to feed on other available flowers that exhibit an alternative colour to their preferred flower type. One hypothesis for the evolution of floral constancy in pollinators is that insects can only identify and handle one flower type or species at a time due to their limited memory capacity.

There are three other hypotheses for the evolution of floral constancy in pollinators. The first is the learning investment hypothesis which refers to the ability of a pollinator to learn a motor skill to obtain nectar from a certain species of flower. Learning these motor skills requires a substantial investment of energy and switching to other flower species could be energetically costly and hence, inefficient and non-adaptive. Furthermore, feeding from one particular plant species increases the insect’s efficiency to obtain nectar from it. The second hypothesis is the costly information hypothesis which states that pollinators stay faithful to one plant species because they know that they obtain a reliable reward from it, i.e. nectar. Hence, the pollinator does attempt to feed on other plant species because it cannot predict the amount of nectar in other flowers and could essentially waste foraging time and energy on flowers that contain possibly less or even no nectar. The third alternate hypothesis is the resource partitioning hypothesis. It states that, in social foragers, flower constancy could benefit the entire colony as if individual foragers specialize on specific flower species, foragers avoid competing with one another. Thus floral constancy would increase foraging efficiency.

In addition, Prof. Stevenson and his colleagues have found evidence for another hypothesis in which toxins such as caffeine are the drivers of floral constancy in pollinators. Evidence for this came from bees being found to be more likely to forage on the same plant species if it contained caffeine and less likely to confuse it with similar signals from other plant species. They have found evidence of plant defence compounds enhancing the memory of reward in pollinators. Honeybees rewarded with caffeine, which occurs naturally in coffee and citrus plant species, were three times as likely to remember a learned floral scent as honeybees rewarded with sucrose alone. Thus, this proposed hypothesis ties the little understood phenomenon of floral constancy in with the little understood ecological role of plant defence compounds occurring in floral nectar.

Admittedly, this love affair is not as rosemantic (pun intended) as Romeo and Juliet’s. However, it is very intriguing nonetheless and the mechanisms behind it are still very uncertain. Exciting new evidence underlying the mechanisms involved is being found by Stevenson and his collaborators and it seems likely that it is not solely Britney Spears who finds toxicity attractive.

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The deviousness of flowers

Chris Parsisson

It should have come as no surprise to us that flowers act as drug pushers to get their evil way. Phil Stevenson of The University of Greenwich and Kew gave a short talk about the loyalty of pollinators to nectar producers.

Flowers have many devious tricks and will stop at nothing to reach their ultimate reproductive goals.  A world before flowers must have been a drab place with wind pollination being the order of the day and clouds of pollen wafting across the countryside in a desperate bid to land on a female plant part and perpetuate the gene line of the parent. No colourful flowers, no enticing perfume, no sweet honey. Just a hay fever sufferer’s nightmare. No wonder some plants formed a partnership with pollinators to streamline the operation.

And what a partnership it was! Insects often took on the role of pollinators and tied their fortunes to the plants’ success as plants tied themselves to the pollinators. Flowers evolved colours and scents to attract insects then often refined their flowers for special partners. Bees and wasps became preeminent in pollination and became dependent on supplies of nectar and pollen for their living. Always lured in by the flowers their co-evolution made both mutually dependent. The beauty of flowers and scents led to human intervention and flowers were developed with multiple petals and constant flowering periods but these developments often led to sterile flowers or loss of scents the need for human pollination. Isn’t it always the way? But who is keeping score? The millions of cultivated roses grown around the world must outnumber the wild roses in hedgerows so again the inclusive fitness of the roses, originally chosen for a brighter or extra petal, was assured. We too were seduced by the flowers into serving their nefarious schemes.

We discovered in recent decades that the colour we see on a flower is not the same as that seen by many pollinators. Bees see more in the ultra violet range and the patterns they perceive on many flowers lead directly to nectaries or to the stamens for a dusting of pollen or to shed some onto the stigma in this joint effort. No wonder many cultivated flowers with their multiple petals, lack of scent and vibrant colours are inaccessible to many bees, the landing instructions are lost and the nectaries have often been sacrificed for more petals. Best leave the cultivated flowers for the humans, enthralled by the flowers’ guile.

We know that some orchids lure male bees in with the promise of quick uncomplicated sex. Like a seaport pimp enticing a sailor down an alley with promises of beautiful girls nearby, the orchid entices him in and delivers nothing. The female bee is really another co-evolved flower and the male gets nothing for his trouble. The orchid delivers its pollen onto the bee’s back and off he goes looking for another flower. The floral equivalent of robbing the sailor and sending him staggering off into the night.

Now, it seems, we find that flowers are demanding loyalty of bees by slipping them drugs without their knowledge. Small amounts of caffeine are included with the nectar at a level thought to be below the taste consciousness of the bee but enough to make it remember the hit it got and return for more. This occurs in many coffee species and also in citrus species. It makes evolutionary sense. All flowering plants are competing with every neighbouring flower. If they weren’t and there were enough pollinators to go around all flowers would be simple in form and give out a minimum amount of nectar. That’s why flower form evolved so dramatically. The cunning flowers need an extra edge to ensure that bees come back to them as long as their flower lasts. Many flowers need a pollinator to visit more than once: to take away pollen to another flower and to bring in pollen. Often the female stigma ripens at a different time to the male anthers to prevent self-fertilisation so multiple visits may be ensured by making a bee remember the little lift it got at a particular plant.

Pollination is a serious business as 65% of crops are insect pollinated. Concerns about sudden hive collapse of honey bees and losses of pollinators are real. Even the managed bees are not enough for all pollination needs so wild pollinators must be carefully watched. Large monocultures may be detrimental to bees as tests have shown that levels of amino acids in some nectar may be harmful if eaten in excess.

Many leads could follow this research as a way to best serve the pollinators but, rest assured, those devious flowers will be still full of tricks.

Image: Wikicommons

Seminar series highlights: Fiona Doohan

wheat

As mentioned previously on the blog, Andrew Jackson and I started a new module this year called “Research Comprehension”. The module revolves around our Evolutionary Biology and Ecology seminar series and the continuous assessment for the module is in the form of blog posts discussing these seminars. We posted a selection of these earlier in the term, but now that the students have had their final degree marks we wanted to post the blogs with the best marks. This means there are more blog posts for some seminars than for others, though we’ve avoided reposting anything we’ve posted previously. We hope you enjoy reading them, and of course congratulations to all the students of the class of 2014! – Natalie

Here are Yutaka Kumagai and Cormac Murphy’s views on Dr. Fiona Doohan‘s seminar“Plant-Microbe interactions – the good, the bad and the ugly”.

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Food security: A game changer for GMOs?

Yutaka Kumagai


The subject of genetic modification has always carried with it a certain level ethical ambiguity in the eyes of the wider public. While quite a significant proportion of the blame for this may be down to misinformation and ignorance, it may also be contributed to the somewhat shady operations of large corporations such as Monsanto. It is inevitably the more shocking or controversial stories that capture the imaginations of the public, and the David and Goliath legal battles between farmers and corporations do not fail to grab attention. Anti-GMO activist groups are also extremely vocal in their fight for organic produce, and many of the articles that may be sourced online are heavily biased in their favour.

On a national level, public opinion is clearly against the notion of genetically engineered organisms, a simple google search of ‘Ireland GMO’ returns multiple hits from anti-GMO sites. Yet while Irish consumers may not approve of GM, it is obvious that many also do not understand the concept. A certain amount of the blame for this ignorance surely lies with the lack of dialogue surrounding the topic, with most of the information broadcast being anti-GMO, without providing much of an explanation. This may even be seen in large scale shops such as Marks & Spencers lauding their wares as non-GM.

However, the benefits of many GM foods are such that surely a system of control would be more profitable than outright ban. In a recent seminar, Dr. Fiona Doohan, a senior lecturer at UCD, gave an insight into the research being undertaken by her team on disease resistance in cereal crops. Specifically, her works focuses on the infection of wheat  and barley crops by Fusarium graminearum and F. culmorum, which are known causes of Fusarium Head Blight (FHB) disease. This causes bleaching of cereal grains, and is harmful to plants and animals. The main toxin produced during infection is deoxynivalenol (DON), which facilitates FHB, and may be attributed as the cause of many of the observable effects. By observing variance in wheat response to DON, Doohan was able to find a resistant genotype. Unfortunately, this resistant genotype carried with it its own set of negative traits, preventing it from use as an effective cash crop. As such, Doohan attempted to identify the specific genes associated with resistance. Expression levels of DON-resistant wheat genes were analysed through the use of microarray testing, with results verified through RT-PCR analysis. This allowed for the identification on orphan (lineage specific) genes involved in the defence pathway activated by DON to be identified. With further research, it will hopefully be possible for this pathogen resistance to be conferred to susceptible wheat strains.

It would be difficult to colour such a development in a bad light, especially considering that wheat is one of the most produced cereal crops in the world. So why is public opinion so against GMO? All GMO food products must pass rigorous testing by the WHO, with continuous assessment taking place once a product is released to the market. While certain GM foods, such as golden rice, do make their way into the public ‘good books’, even these success stories are not as widely known as they ought to be. Yet, it can only be hoped that the current research being undertaken by Doohan, and those like her, will turn the tide in this war of misinformation.

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Give us this day our daily bread

Cormac Murphy


Wheat and its by-products have been such an integral part of human livelihoods for so long they’ve become religious artefacts. They are everywhere, just ask a despairing coeliac. But for as long as we’ve been cultivating wheat, our health has been intertwined with that of the crop. Poor weather, mycological diseases or trampling could take both the income and vital nutrition from a family. And if an infected stalk was reaped and processed into food, it could pose a real threat to the health and sanity of a community. Some classic examples are the cases of ergot poisoning that lead to mass hysteria and witch burnings across Europe in the middle ages. Today with wheat representing the second largest source of calories for all mankind, the health of our wheat crop has never been more important.

And it’s up to people like Fiona Doohan, Director of the UCD Earth Institute to cultivate strains of wheat that can produce enough to meet the need of a hungry word (and economy) that are resistant to these harmful pathogens. Dr. Doohan’s lab focused on the fungus Fusarium graminearum, which causes fusarium head blight  (fhb) a disease that devastates wheat and barley resulting in billions of dollars loss in crops annually. Dr. Doohan looks at the actions of the fungus focusing on one of the main toxins it produces, deoxynivalenol (DON) also charmingly known as vomitoxin. DOM interferes with protein synthesis and when applied by itself to the wheat heads  produced the bleaching characteristic of fhb. In low levels DON has been found to prevent cell death, whereas at high levels DOM causes it. This facilitates the switch from vitotrophic to necrotrophic which is a key part of the disease’s progression and spread. Dr. Doohan looked at 2 cultivars of wheat; Remus which was susceptible to DOM but produces an economically viable crop, and CM 82036 which wile being a less viable source of income is resistant to DON.

Both were treated with DOM. After 4 hours the plants were observed and RNA samples  and run through a custom microarray were taken from both plants, this was repeated after 24 hrs. The DON was seen to have a greater effect after 24hrs in the Remus both visibly and in terms of disrupting protein synthesis. In the resistant strain the majority of the proteins that seem to be produced in response to the toxin were “unclassified” the products of “orphan genes”. Orphan genes are genes with very specific lineages that we currently have very little information on in databases. Doohan’s team found that these particular orphans seemed to be linked to stress responses in the plant. There was also evidence that they were fast evolving, with even close phylogenic relatives baring genes with as little as a 50% match. They appeared to be more toxin specific than tissue specific, arising at the points where DON was introduced. These seem like the key to DON resistance and potentially the key to transferring that resistance. A yeast 2 hybrid screen was then used to examine the interactions of these orphan proteins with other proteins known to be active in stress resistance. In these tests a related mycological toxin T-2 was used on the yeast as yeast is highly DON resistant. Just to drive home the seriousness of these toxins T-2 is the key ingredient in now banned biological weapon known as “Yellow rain”. The results of these tests indicated that the orphans are involved in the activation of the SnRK1 stress resistance pathway thought how it interacts remains unknown.

These experiments have given us a glimpse at a potential new tool to protect the food security of the world. But with so little known about the genes involved, a lot of work still needs to be done. Some wheat genomes have recently been sequenced and the information that can be gathered from them may yet shed light on our orphans. As with any GM organism, particularly one that’s intended for human consumption, there must be a great understanding of exactly how these changes will affect the makeup of these plants.

Image: Wikicommons

Dig for victory

In a previous post I showed what I think being a palaeontologist is all about, especially the point that palaeontologists are different from oryctologists. The first ones study changes of biodiversity through time, the second ones extract fossils (but again, both are far from exclusive).

Here is a short summary of  experience working at Upper Cretaceous excavation sites in the South of France (that’s around 80-65 million years old) namely in the Bellevue excavation site in Esperaza run by the Musée des Dinosaures.

First step is to find a place to dig.

Step 1.1: find something

Why along the road? It doesn’t have to be but it has two clear advantages: you can park your car next to it and it’s usually rich in fresh outcrops of rock (where you can find more fossils than in a crop field!).

Step 1.2: try again and again!

The second step, once you’ve decided that there might be something in the outcrop you’ve just explored, is to remove all the “annoying stuff”. To palaeontologists that obviously means all the wonderful fauna and flora and their associated environment (usually soil) that are growing above the potential fossiliferous site (how rude of them!).

Step 2: remove all the annoying stuff

Once you’ve removed the layer of living stuff, you can start the long and interesting part: hitting rocks with a hammer and a pike during the hottest days of summer.

Step 3: start hitting the rocks
Step 4: find something (hopefully!)

Finally, with a bit (a huge bit) of luck, you’ll find a fossil that was worth all this hassle.

Step 5.1: clean the fossil

Once you’ve found the fossil, the first step is to clean the surface facing you and start to build a trench around it in order to pour plaster over it and bring it to the lab. As you can see, paint brushes are useless here too: the hammer and the pike make ideal tools for the surrounding trench and an oyster knife and a smaller hammer do the cleaning jobs. Oh yeah, and a tube of glue. After around 80 million years, the bones get a bit fragile.

Step 5.2: clean the fossil… again!

The last step is to properly clean the fossil in the lab by removing it from all the surrounding rock. The best tools are mini pneumatic-drills and loads of patience. When all that is done, the palaeontologist can start to work on the fossil.

You can find more impressive pictures on the Musée des Dinosaures webpage.

Author: Thomas Guillerme, guillert[at]tcd.ie, @TGuillerme

Images: Thomas Guillerme and Sébastien Enault (with the kind authorisation of Jean Le Loeuff). Feature image: http://www.libraryofbirmingham.com/

Seminar series highlights: Amy Pederson and Christine Maggs

apodemus
Apodemus sylvaticus, (wikicommons)

As mentioned previously on the blog, Andrew Jackson and I started a new module this year called “Research Comprehension”. The module revolves around our Evolutionary Biology and Ecology seminar series and the continuous assessment for the module is in the form of blog posts discussing these seminars. We posted a selection of these earlier in the term, but now that the students have had their final degree marks we wanted to post the blogs with the best marks. This means there are more blog posts for some seminars than for others, though we’ve avoided reposting anything we’ve posted previously. We hope you enjoy reading them, and of course congratulations to all the students of the class of 2014! – Natalie

Here’s views from Sharon Matthews on Dr. Amy Pedersen‘s seminar, “A systems ecology approach to infection and immunity in the wild” and Dermot McMorrough’s take on Professor Christine Maggs‘ seminar, “Invasive seaweeds and other marine organisms”.

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It’s a ‘wormy’ world we live

Sharon Matthews


We all walk around thinking I will never have parasites but apparently our chances of becoming infected are high because there are around 1,400 species of parasite that can infect humans.  If this news wasn’t bad enough, Dr. Amy Pederson informed us at her seminar that our chances of becoming infected with two or more parasites at the same time, is also very high.  Dr. Pederson explained that through her work, she hopes to understand the phenomenon of co-infection and the interactions between these parasites in a host that drive this trend.

Dr. Pederson and colleagues showed through a meta-analysis of studies that co-infection is often associated with higher parasite abundance and a negative effect on human health.   The interspecific interactions between parasites in a host can influence disease severity and transmission through the immunological responses of the host, making an environment more accessible for another species.

To investigate this phenomenon, Dr. Pederson chose to do a perturbation study using the wild species of wood mouse, Apodemus sylvaticus as a host system. A lot of past studies on parasitism have used a laboratory mouse model because of accessibility to the subject and ease of manipulation and control of confounding factors.  I think it is very important to also have wild animal model systems because they strongly represent the variation and dynamics that would be seen in a real-life infection scenario.  Also the wood mouse can be parasitised by 30 different species (both micro and macro parasites) and up to 70% of them can be co-infected which resembles the situation in humans.

Dr. Pederson wanted to determine the nature of the interactions among the parasite community in the woodmouse and to assess the stability of the community so she used the anthelminthic drug ivermectin to perturb the system.  This drug targets nematodes, the most abundant member of this community so interactions between these and other groups should be apparent from perturbing their numbers.  I liked the fact there was a longitudinal aspect to the experimental design as it allowed the effects on the parasite community to be analysed over time.  All of the wood mice were tagged at the beginning and there were 3 different treatment groups: controls that received water at every monthly capture, a single treatment group and a group that received treatment of ivermectin at every capture.  Faecal and blood samples were taken at each capture to check for levels of infection through egg counts and blood smears.

The results showed that treated mice had a 71% lower probability of infection 3 weeks after treatment than control mice but no difference was seen after one to two months because nematode numbers increased.  This suggests that the effect on nematodes was short-lived and the community of parasites was resilient, returning to the original state before perturbation.  This pattern for reduction and then returning to normal levels of infection was seen in Heligmosomoides polygyrus, the most abundant nematode in the community. This parasite shares an infection site with the protist, Eimeria hungaryensis.  As the numbers of H. polygyrus reduced, the numbers of E. hungayensis increased and then returned to original levels once H. polygyrus recovered.  This effect on a non-target species suggests that there may be a competitive interaction between the two species.  They both occupy the same niche in the gastrointestinal tract of the wood mouse and reduction of numbers of the more dominant nematode may have given the protozoan a chance to use resources not normally available to it to colonise.  No treatment effect was seen on any of the other parasite species.

The work of Dr. Pederson is very interesting and it gives us a window into the dynamics underlying co-infection.  This work will broaden our understanding of the world of parasites and how they interact and will help inform us in our choice of treatment and which species may be effected by it.  The one thing I was happy about coming out of the seminar was the fact that Dr. Pederson said, “those who are wormy usually remain wormy”.  In other words, individuals with high burdens of nematodes (worms) show a tendency for reinfection over time.  That leaves me with some hope that for at least now, I remain wormless and if the stats are anything to go by, I have a chance at remaining wormless for the forseeable future.

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Review of Christine Maggs’ seminar

Dermott McMorrough

The effect of invasive species is, by now, well documented and is often brought to light when species’ such as grey squirrels, American crayfish, zebra mussels, and Japanese knotweed turn up in a new environment; an event all to familiar to ecologists. Those listed above are just some of the examples of ‘alien’ species known to kill off native creatures and plants when they become established in new habitats. In Ireland, for example, the role of the North American Grey Squirrel has been well studied due to the effect they have had on our native Red Squirrel since their introduction into Co. Longford in 1911.

Invasive species have an incredible ability to migrate and establish themselves thousands of miles from their origin, either organically, or often with a helping hand from humans for example by hitching a ride as stowaways on trade ships or in ballast tanks, as has been the case with Zebra Mussels. The shared ability of the aforementioned species to colonise vast areas is no mere coincidence. Several species are introduced to new ecosystems, accidentally or otherwise, but relatively few have enjoyed such enduring success. Aside from threatening native species of plants and wildlife, the incredible growth of these species can lead to them negatively impacting on anthropogenic activities, whether it be fouling mooring lines or clogging water intake pipes as has been the case at the Guinness brewery at St. James’ Gate.

Professor Maggs’ seminar began with an explanation of how an invasive species can colonise an area. While her background was evidently in Botany, she made a particular effort to appeal to the zoologists in the audience with numerous references to the role of oysters in the spread of macro algae. Her research covers a fairly broad area, and pinpointing an exact research question has eluded many in the room. We were, however, treated to a synopsis of how invasives go about establishing themselves, and the methods often employed to prevent this process or eradicate it if it has already taken place. For example, methods such as immersing oysters in concentrated brine or flash boiling them have proven effective in fighting the spread of invasive algae, which use the oysters as a vector.

The spread of an invasive alga would not seem like an immediately worrying problem to those untrained in ecology. As with many problems in science, it is not until the issue directly affects the people in charge of policy making that anything is done to rectify it. This unfortunate criterion was evident in one of the examples used by Professor Maggs. In 2008, the city of Qingdao was due to host the Sailing event of the 29th Olympic games, but just weeks before racing was due to start, an algal bloom covered Qingdao bay in a thick layer of Enteromorpha algae. The presence and strength of the bloom was largely accredited to the high levels of nitrates in the water as a result of farmland runoff, coupled with higher than average temperatures and rainfall. During the seminar, the use of giant plastic sheets in San Diego Bay was seen as an American answer to an ecological problem, but it worked. Credit where credit is due. The imminent deadline of the Olympiad prompted the Chinese authorities to tackle this ecological disaster with what has to be the most wonderfully Chinese way possible: by ordering 20,000 locals to line the beaches, and man over 1,000 fishing boats to rake in the bloom manually. Sure enough, within a few days over 100,000 tonnes of the algae had been shipped out of the bay.

Algal bloom in Qingdao. Picture from the Guardian
Algal bloom in Qingdao. Picture from the Guardian



Increases in the amount of travelling done by humans and more importantly freight over the past century has led to an explosion in the ranges of successful invasive species, to the point at which one must wonder how endemic species can survive at all? The increased efficiency of our transit routes has also meant that invasives no longer rely on miracle migrations, such as that likely undertaken by the Iguana of the Galapagos. With the ever-increasing demand for fresh exotic produce in the developed world, the ships are getting faster, the coolers are getting colder, and the chances of an invasive species making it’s way around the world in less than 24 hours, perfectly preserved in Tesco wrapping and ready to colonise a new ecosystem have been made just that much easier. It seems that when it comes to being an invasive species, every little helps.

The Biology of Godzilla

Warning: minor spoilers ahead!

 

godzilla

He’s back! Originally a metaphor for the horrors of the bombing of Hiroshima and Nagasaki in a heavily censored post-war Japan, Godzilla become a cultural icon whose name is known across the world. His latest incarnation is in Gareth Edward’s film which I saw on its opening weekend. And as a biologist I can’t help but watch with an eye towards the plausibility of the gigantic reptile and his opponents.

I was pleasantly surprised to find that, like Edward’s previous film Monsters, care had been taken to ensure that the titular creature and his adversaries had realistic behavioural traits. Of course, we are dealing with animals 100m tall so some artistic licence is being taken, but I was impressed with how the creatures had clearly been considered as biological organisms and I thought would be fun to discuss the monsters of Godzilla from a biological perspective. I will have to include some minor spoilers so do not read unless you have seen the film or don’t care. You have been warned!

Despite being the titular subject of the film, Godzilla is arguably not the protagonist though he is undoubtedly the saviour. The catalyst for the action is the birth of a MUTO. or Massive Unidentified Terrestrial Organism. It is soon apparent that the “terrestrial” part of its name is a misnomer as it takes to the skies upon gigantic wings. A second MUTO is discovered, though this time the term “terrestrial” holds true. This animal is also significantly larger than the first one and the scientists quickly recognise that rather than these being two different species, they are a male and female of the same species. The male is a highly mobile but smaller creature while the female is a much larger and less mobile animal.

This sexual dimorphism is common in the animal kingdom. We are used to thinking of males as the larger sex but this generally only occurs in territorial or polygamous animals where size is important in attracting and maintaining females. In species where these factors are not important females are often larger as they have a larger reproductive burden. Males can produce vast quantities of sperm at even relatively small sizes while the number of eggs a female can produce is directly related to her size. The larger a female can get, the more eggs she can produce. This type of sexual dimorphism is common in insects, spiders and fish and occurs occasionally in other taxa including mammals such as the spotted hyena and blue whale. Probably the most extreme example of this sexual dimorphism is seen in Ceratoid anglerfish, a family of deep sea fish whose low densities mean that finding a mate can be extremely difficult. To get over this problem the males have become parasitic, attaching to the first female they find and slowly lose their internal organs as their circulatory systems merge with that of the female. Their body atrophies until they are little more than testicles, ready to fertilise the female whenever she requires.

Ceratiids
Female ceratiid dwarfing her male companion http://bit.ly/1n8Fx68

The smaller size of the males means that they are often more mobile than the females. Indeed, flightless females and volant males are not a construct of the film but are found in real life too. Scale insects and stick insects, among others, have this dichotomy of locomotive strategies. The larger an animal is, the more energetically costly it is to defy gravity. In addition, flying can open up the possibilities of predation. It is therefore safer for females to remain relatively sedentary and wait for males to come to them. In order to seek out as many females as possible, travel must be energetically cheap for the male. This means covering as much ground as possible which is easiest if they can fly which means being light. This is seen in the film as the male travels across the entire Pacific ocean in less than the time it takes the female to travel from Nevada to San Francisco.

The male MOTU attracts the female through the use of vocalisations: he calls to her. In the animal kingdom, too, it is predominantly the male who calls to attract females. From cicadas to penguins , males across the animal kingdom use their voice to tell females how great they are and what excellent genes they have. Blue whales have calls that can cross oceans so the male MUTO’s call to the female that crosses the Pacific is not inconceivable, though how it then travels across land to Nevada is stretching plausibility somewhat.

When the MUTOs finally meet they engage in a bonding ritual commonly seen in species who pair-bond. Species such as penguins and albatrosses, where pairings are maintained across more than one season, have ritual greetings that reaffirm their bonds. The MOTUs have so far been insectoid in their behaviour so this may seem out of keeping as pair bonding is commonly found in warm blooded animals. Yet there is an insect that pair bonds, the Lord Howe stick insect, although the female is also capable of reproducing through parthenogenesis. This may explain why we don’t actually see the MOTUs mate before the female lays eggs: she is capable of reproducing parthenogenetically. There are some species which are parthenogenetic but still require sperm to stimulate egg production. While we clearly see the female carrying eggs prior to her meeting the male, it may be that contact with the male, however brief, is required to stimulate egg laying.

Before the laying of eggs and after the pair bonding comes the gift giving. Nuptial gifts are common in the animal kingdom across many taxa. Sometimes these gifts come in the form of packages of highly nutritious sperm which the female eats, often while the male mates with her. The larger the gift, the longer she eats and the greater the chance she has of fertilising the eggs. In other species the gift is in the form of food the male has captured. It is this type of nuptial gift that the male MUTO offers the female, in the form of a nuclear bomb. Whatever rocks your boat!

Scorpion fly with nuptial gift

The final two behaviors we see are nest guarding and emotion. The female MUTO protects her nest from Godzilla and shows grief and anger when her nest is destroyed by our plucky human protagonist. Many animals guard their nests and offspring. We are used to seeing mammals and birds protecting their young but this behavior is also present in insects, spiders and fish among others. For some animals, such as the octopus,  this nest guarding is fatal as they are so dedicated to their protective role that they do not leave, even to eat, while the eggs develop. The grief that the female expresses is also seen in real life, though so far it has only been seen in mammals and birds. However, given the level of intelligence shown by the MUTOs, grief is not an inconceivable reaction.

The behaviours exhibited by the MUTOs are surprisingly biologically plausible. In a genre where science is often used only as far as necessary and scientific words are often thrown around without any consideration as to their suitability it was a surprise to see so much care going into these animals. This is not to say that everything about the creatures was accurate. Godzilla is 100m tall, the female MUTO is similar in size and the male, while smaller, is still several storeys tall and is capable of flight. A recent discovery of the largest dinosaur to date, a titanosaur from Argentina, was ‘only’ 20m tall and weighed just under 80 tonnes. The reason animals do not attain the size seen in fiction is a combination of the effects of gravity and the strength of organic materials. As animals get bigger their volume grows faster than their length and this puts increasing pressure on their skeleton. There is a size above which it is impossible to function and it is unlikely that anything larger than the recent dinosaur discovered will be significantly surpassed. Godzilla and his kaiju compatriots are fortunately physically impossible on our planet. Equally, their diet is implausible and raises the question of why, if they can absorb radiation, do they need mouths? The characteristics of Godzilla himself are even less biologically sound, but many of his most egregious characteristics date back to his creation, when creating a powerful metaphor for violent destruction was more the more pressing concern.

Dinosaur bone
That’s one big dinosaur! See the BBC news article http://bbc.in/1mG5oE0

Giant monsters are a staple of genre fiction and, like the transporters of Star Trek or the time travel of the Terminator films, if you cannot suspend your disbelief in that regard then you’d better not watch. But often it is the case that you are willing to suspend some disbelief but then the writer or director expects you to go further and asks you to throw any desire for realism out of the window. The pleasant surprise with this film is the effort the filmmakers have made to make their creatures feel real. They looked amazing, moved realistically and, most surprisingly of all, behaved realistically. I hope that this is the first of many films that exploit the amazing diversity of real life to their advantage, rather than make things up. When real life is so diverse and bizarre, why bother with fiction? Save that for the plot!

Author: Sarah Hearne, hearnes[at]tcd.ie, @SarahVHearne

Images: Wikicommons

Seminar series highlights: Fred Marion-Poll

drosophila

As mentioned previously on the blog, Andrew Jackson and I started a new module this year called “Research Comprehension”. The module revolves around our Evolutionary Biology and Ecology seminar series and the continuous assessment for the module is in the form of blog posts discussing these seminars. We posted a selection of these earlier in the term, but now that the students have had their final degree marks we wanted to post the blogs with the best marks. This means there are more blog posts for some seminars than for others, though we’ve avoided reposting anything we’ve posted previously. We hope you enjoy reading them, and of course congratulations to all the students of the class of 2014! – Natalie

Here’s thoughts from PJ Boyce and Joe Bliss on Dr. Frederic Marion-Poll’s seminar; “Why do we avoid bitter molecules (and why do flies avoid them too)?”

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A Bitter Taste for Deadly Sweets!

PJ Boyce

Have you ever held a cockroach in your bare fist? Have you felt its wings flicking against the inside of your hand? Its feet sticking to your skin? Personally, I’ve touched and held a lot of weird and wonderful things but never have I been so thoroughly disgusted as when I held a cockroach. Its such an…icky…creature! So why is it in this modern age of mass extinctions, that the cockroach has managed to persist, even considering the considerable amount of effort on our part to exterminate the little devils! I can’t answer that. What I can do is explain yet another way in which these tough little guys are managing to foil us again: They are avoiding our poisoned bait traps! How? By changing how they think about them!

Of course, I use the term ‘think’ loosely. Really, they are changing how they perceive the bait and this all boils down to how they taste it. Gustation, the sense of taste, in insects, is probably best understood in the old, reliable, Drosophila. The fruit fly’s well documented genome lends itself to many different kinds of mutation experiments, including, as Dr. Frederic Marion-Poll was delighted to explain to the gathering of neuroscientists, zoologists, and other interested parties at his talk, experiments on taste.

Of Marion-Poll’s many examples of experiments performed on the humble fruit fly, one in particular is very relevant. They were interested in seeing whether olfactory receptors (associated with smelling) expressed on taste cells could trigger a ‘taste’ response to an oderant (smelly) stimulus. Interestingly, they observed that not only could the flies taste the ‘smelly’ molecule (using electrophysiological measurements) but also that the behaviour of the flies differed depending on where the olfactory receptor was expressed. When the receptor was expressed in a sweet tasting cell (initiating a sweet response), the fly was attracted to the stimulus but when the receptor was expressed in a bitter tasting cell (initiating a bitter response), the same stimulus triggered an aversive response and repelled the fly.

‘What has this got to do with cockroaches?’ I here you ask. Well, the key finding to take from this experiment was that it didn’t matter what chemical was being tasted. What mattered was where the receptor was being expressed. So, when I heard about populations of cockroaches learning to avoid poisoned bait I immediately thought of the work of Marion-Poll and co.

The bait that has been used for the cockroach traps is glucose, the (usually) universally sweet molecule. On its own and under normal circumstances, cockroaches can’t get enough of glucose. Add a little poison to this delectable treat and the cockroaches were literally killing themselves to get a tasty mealful. Recently, however, populations of cockroaches have been discovered that avoid glucose, whether or not it has been poisoned, in favour of other, usually less desirable foods. More than this, they also show the classic ‘bitter response’ (common to almost every tasting animal) to tasting glucose. This indicates that they are now tasting glucose as a bitter molecule!

‘Wouldn’t it be better if the cockroaches evolved to recognise the poison instead of disregarding all glucose?’ you might ask, and you would be right, except that’s not how evolution works, is it? It is possible that a cockroach could evolve a gene that makes a receptor that detects the poison. A much more likely scenario, however, is that the cockroach accidentally expresses an already existing gene, namely the glucose receptor, in a bitter tasting cell. By doing this, it would react to glucose as if it were a bitter molecule, thereby having an advantage over all the gullible cockroaches in the presence of poison. Is this mechanism feasible, though? Almost certainly! When we consider that olfactory receptors can be functionally expressed in taste cells, it’s not too much of a stretch to suggest that a receptor which already exists in a sweet taste cell could ‘hop the fence’ to a bitter taste cell. I think it a much more prudent question to ask: ‘What are we going to do about the impending cockroach apocalypse ’cause we just can’t seem to stop these guys!?’

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A Taste of Insanity?

Joe Bliss

morpheus
Image Source

What is real? How do you define, ‘real’? If you’re talking about what you can feel, what you can smell, what you can taste and see, then real is simply electrical signals interpreted by your brain.” – Morpheus, The Matrix, 1999


The 1999 film The Matrix makes us question the reality of our own existence. The main protagonist Neo discovers that his entire world is an electronic simulation, created by sentient machines to occupy his mind while they harvest the energy generated by his metabolism.  For the purposes of the rest of this blog, I will make the assumption that the world we find ourselves in is not a simulated reality. However after a research seminar given by Fredric Marion-Poll, I find myself debating the reality around me. Is sugar sweet? What is sweet?
These may sound like the questions of a man on the verge of insanity, but they are interesting issues to raise and are without obvious answers. We can describe a colour by its wavelength and sound by its pitch as these are physical, measurable quantities, but there are no inherent properties of a chemical that define it as bitter or sweet.
Taste is a sensation produced when a chemical reacts with a receptor cell in the taste buds of the tongue. However there are different taste receptor cells, including one for bitter tastes and one for sweet tastes. These cells have an array of unique receptors for a number of different chemicals. If a chemical matches with a receptor on a sweet cell it will stimulate the cell to send a ‘sweet’ signal to the brain.
Marion-Poll suggested that animals have adapted to associate harmful chemicals with ‘bitter’ which stimulates an evasive response. He showed a video of this recognisable ‘bitter response’ in both an insect and in this must-see video of a child being fed grapefruit juice. The research he presented also highlighted that taste has more levels of complexity than just simple recognition. In one experiment, fruit flies were offered a choice of four fructose food sources containing varying levels of strychnine, a highly toxic substance. As expected, flies avoided this toxin as it stimulates a bitter taste receptor. However even when the bitter tasting cell was destroyed in the fly, that strychnine laced food source was still avoided. This suggests that the strychnine also inhibits the sweet tasting cells, further enhancing toxin avoidance. However this was not the case for all the bitter chemicals they tested and the process is not yet fully understood.
As a final intriguing conclusion to the seminar, research was presented which found that some cockroaches in the USA have adapted to avoid glucose baited traps. The sugar bait was made less sweet for these cockroaches which now taste the glucose as bitter, making them avoid the traps. So this begs the fundamental philosophical question; what is the true taste of sugar? As Morpheus might say, it is whatever your mind chooses it to be.

Image: Wikicommons

What is(n’t) palaeontology like?

paleontology

After rereading Sive’s excellent blog post on what is a zoologist or at least what is it like to study it, I remember having a slightly similar difficulty in explaining my background in palaeontology. Reactions range from: “Oh… Palaeontology? That’s like the origins of humans and stuff?” or “So you go on excavations and find ancient Roman pottery?” to “Bheuuh, want another beer?”. What frustrated me is that none of these reactions are correct but neither are they totally incorrect (especially the last one!).

Palaeontology is not archaeology

Most people that have only a vague idea of what palaeontology is are usually not big fans of Jurassic Park and don’t know Alan Grant so they usually associate palaeontology with Ross Geller or Indiana Jones. Being not a big fan of TV series, I don’t know whether Ross is a good representation of the reality of life as a palaeontologist but I know that Indiana is not. Not even a little bit. He’s an archaeologist. That might be a nerdy detail for some but to understand what palaeontology is about, it is important to understand the difference. Even though both archaeologists and palaeontologists study the past based on what they find in the ground (and in books!), the time scales involved make the two disciplines impossible to compare. Archaeologists are mainly interested in human culture (they might find animal bones but they are usually the fragments of crafted objects). In contrast, palaeontologists are interested in the remains of life that occurred before human civilisation. Therefore we have two very different time scales here: from years to centuries or, at a push, millennia for archaeologists and from hundreds to millions of millennia (or billion of years) for palaeontologists.

Palaeontology is not about excavations

Palaeontologists do not excavate fossils, that’s a job for Oryctologists. Okay, I’m being picky with the terms here but, again, the distinction is important. Most palaeontologists are also oryctologists, meaning that they go into the field and do excavations as the basis for their scientific work (yeah, in the end, that’s not a cliché, one of the nicest parts of the job is field work!). However, not all palaeontologists are oryctologists (even though most are) and many oryctologists are not palaeontologists. Again, palaeontology is not only about digging up fossils and putting them in museums (contrary to what this song suggests), it is about the study of changes that occurred on our planet through deep time (geography, climate, etc…) and how they affected living organisms (evolution, extinction, etc…).

JP-Digsite

While we’re on the subject of oryctology, there is a huge public misconception about excavations. Most people that have seen Jurassic Park might think that, in the 90’s, one could just go into the field armed with nothing but a paint brush and happily stumble across a complete Velociraptor (Deinonychus!) skeleton which just had to be cleaned out from the surrounding layers of dust. This scenario would certainly make palaeontology way more straightforward and easy but it would also mean that excavations would be just boring routines where a hoover would do a better job than a naively enthusiastic undergrad student!

Even though excavation techniques are at least as numerous as excavation sites, the paint brush must be one of the rarest tools. Personally, I’ve tried things like hammering a cliff with a pike, shoveling dust and blocks of stone, digging in solid clay with an oyster knife or sifting tons of bags of sediments after diluting it in acid in a lab. None of these activities are similar to the restful act of flicking away sand with a brush (but they’re still a lot of fun!).

Palaeontology is not dusty

The two points above are understandably confusing for the general public because of the Hollywood image of palaeontologists, depicted as “adventurers, not really serious, but entertaining” (to translate a quote from Eric Buffetaut’s book “À quoi servent les dinosaures?”). One might think that other scientists would have a better understanding of palaeontology. However, even if they generally understand the discipline and its implications better than the general public: “Paleontology has a reputation as a dry and dusty discipline, stymied by privileged access to fossil specimens that are interpreted with an eye of faith and used to evidence just-so stories of adaptive evolution” (Cunningham et al 2014).

Thankfully, however, the discipline that studies traces of evolution has not escaped evolution of its own. The “privileged access to fossil specimens” has been replaced by either huge online databases (just one example and one other among thousands) or accessible and well-curated collections. The “eye of faith” has been replaced by X-Ray tomography, Surface scanners and synchrotrons; and the “just-so stories” are now replaced by integrative studies leading to a new vision of the history of life

Palaeontology is… great

The differences between a nerdy “Indianajonesomorph” oryctologist that knows all of the dinosaurs’ names by heart and a realistic palaeontologist are what makes palaeontology so interesting. More than the taxonomy, taphonomy, comparative anatomy and cladistic tools that palaeontologists use, palaeontology is about the idea that everything is constantly changing and that we live in just one fleeting moment in the vast history of life.

However, I still like the image of the “adventurers, not really serious, but entertaining”… As long as palaeontologists don’t take this image seriously themselves!

Author: Thomas Guillerme, guillert[at]tcd.ie, @TGuillerme

Images: Wikicommons

Seminar series highlights: John Hutchinson

As mentioned previously on the blog, Andrew Jackson and I started a new module this year called “Research Comprehension”. The module revolves around our Evolutionary Biology and Ecology seminar series and the continuous assessment for the module is in the form of blog posts discussing these seminars. We posted a selection of these earlier in the term, but now that the students have had their final degree marks we wanted to post the blogs with the best marks. This means there are more blog posts for some seminars than for others, though we’ve avoided reposting anything we’ve posted previously. We hope you enjoy reading them, and of course congratulations to all the students of the class of 2014! – Natalie

Here’s Kate Minogue and Rosie Murray’s blogs inspired by Professor John Hutchinson‘s seminar, “Six-toed elephants and knobbly-kneed birds! Case studies in the evolution of limb sesamoid bones.”

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Them bones them bones need………investigating!

Kate Minogue

When a seminar begins with a stuffed cat photo-bombing with the crowd you know its not going to be your usual type of research seminar, and what John Hutchinson discussed during his talk in Trinity College Dublin was far from the norm. The acclaimed scientist and author of the hugely popular blog “What’s in John’s freezer?” kept the audience intrigued throughout. From six-toed elephants to two-knee-capped birds the diversity of sesamoid bones was dealt with in great detail and, more importantly to an audience of previously oblivious zoologists, their evolution over time gave us some amazing new insights.

Firstly I think its important to begin as Hutchinson himself did. By explaining what a sesamoid bone is. They are essentially small, rounded masses embedded in certain tendons and usually related to joint surfaces. They can be found in the knee, hand, wrist and foot of the human body. Hutchinson himself explained them as a waste basket of bones that “ sit in funny places”. By looking at different species which possess these bones in certain locations, Hutchinson began investigating their function and the role they play in locomotion ability. It was through his work in this field that these small, awkwardly located and previously misunderstood bones were credited with giving greater mechanical advantages to an organism by allowing a change in direction of muscle force.

The most interesting part of Hutchinson’s work, from my point of view, was his research on elephants’ feet. By looking deeper into the composition of the foot of present day elephants and past remains he was able to highlight an evolutionary change that has occurred over millions of years. Looking at an elephant you would consider them to be very flat footed animals. However Hutchinson’s research proved this observation to be incorrect. By dissecting present day elephant feet (from that famous freezer of his) he was able to show that they are in fact pointed-toed animals. At the rear base of their foot they have a mass of fat which causes the bone structure of their foot to be tilted ( almost as if they were wearing a high wedge made out of fat). But it was what he found within this mass of fat that make this unlikely foot structure functionally possible. He identified a sesamoid bone embedded within, which was acting as a sort of prop along with the cushion of fat. This bone was later referred to as a pre-digit as it has lost its tendon connections over time and now acts more like projections from the base such as digits. The adaption of the sesamoid bone in the foot of the elephant over 40 million years ago has allowed elephants to change their posture from a once flat footed animal to a very unusual large mammal with a tilted foot presumably giving the animal better mobility.

X-ray image of an elephant's foot. Picture from "What's in John's freezer?"
Elephants walk on a high-heel fat pad. Picture from “What’s in John’s freezer?


The panda is another example that Hutchinson touched on to highlight the use of a sesamoid bone to increase mobility. Instead of evolving an opposoble thumb to aid in grasping bamboo and feeding they use an enlarged sesamoid bone to act as a thumb instead. This adaption has fulfilled its role perfectly and allowed pandas to continue to feed on their exclusive food source, as long as it exists.

Leaving Hutchinson’s seminar I found myself questioning what else we are misunderstanding in the animal kingdom. How have these sesamoid bones which appear to have a huge role in mobility and muscle function pretty much escaped our attention till now and what else are we missing? Hutchinson’s work is a clear example that if you question the unlikely you could just discover something unexpected. Who would have thought it, a 6-toed, high-heels-wearing large mammal! It just doesn’t get better than that, or does it….?

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HOW does the chicken cross the road?

Rosie Murray

While a chicken’s reasons for crossing a road have long been fodder for comedians (the not-so-funny ones), science is less concerned with its motives, and more with its locomotives (that is, HOW chickens cross roads).

Locomotion in modern birds (Neornithes) has two remarkable features; feather-assisted flight and unusually crouched hindlimbs, for bipedal support and movement. I will focus on the issue of crouched hindlimbs.

As has been known for decades, modern birds are dinosaurs (even comparatively rubbish birds like chickens). So, the way birds – living dinosaurs – move is obviously a vitally important source of data for understanding how locomotion worked in extinct dinosaurs.

But birds have some unusual features that set them apart from all the other dinosaurs. A major difference is that birds don’t really have tails, or, if they do, they’re fairly negligible, feathery things. We know that all the other dinosaurs had really big, long, meaty tails. So, somewhere on the way to birds, the tail became so reduced in size that it has almost been totally lost.

The vast majority of land animals, including ourselves, move forwards by swinging the entire leg back-and-forth from the hip (hip-driven locomotion). However, birds keep their hips extremely bent; pointing their thighs forwards, and move around mostly by swinging the lower leg from the knee (knee-driven locomotion). This bent hipped, knee-driven style of moving gives them a characteristic “crouched” look.

But, let’s start at the very beginning. In order to move, terrestrial animals exert a force against the ground to support and then move their body. The reaction force of the ground (GRF) is directed at, or close to, the centre of mass (CoM). This stabilizes the body as it moves position. The GRF is mainly vertical during the mid-phase of locomotion. The mid-phase is when the hindlimb is poised beneath the body on its way forward. Bipedal animals such as birds use a single supporting limb for most of this stance. Therefore the foot of this limb must be placed directly underneath the CoM to exert the vertical GRF. The joints of the limb must also be suitably positioned so that the antigravity muscles can push against the ground in such a way as to move forward without losing balance. The location of the CoM is therefore a major determinant of the limb orientation at mid-stance (Fig. 1)

Living tail-less dinosaurs (A) such as chickens have a centre of mass (black/white) located far forwards in the body. To cope with this they keep their feet forwards by bending their hips and swinging the leg from the knee, which is very unusual. Extinct dinosaurs with large tails (B) would have a more rearward centre of mass. This means they may have had stood straighter and swung their legs from the hip, like most other animals
Fig. 1: Living tail-less dinosaurs (A) such as chickens have a centre of mass (black/white) located far forwards in the body. To cope with this they keep their feet forwards by bending their hips and swinging the leg from the knee, which is very unusual. Extinct dinosaurs with large tails (B) would have a more rearward centre of mass. This means they may have had stood straighter and swung their legs from the hip, like most other animals. Image source: The Guardian

 

Losing the tail means that relatively more of a bird’s mass is at the front of the body, resulting in a more cranial CoM. To remain balanced, the feet and legs also need to be placed further forwards. And, one consequence of the crouched, knee-driven way birds walk and run is that the leg joint that does most of the job (the knee), can be stuck a lot further forwards on the body than the main joint other animals use (the hip). So a lot of the weirdness of bird locomotion may just be related to them having to put their legs more towards the front of the body, to match the CoM.

To test this, a team of scientists lead by Bruno Grossi took a simplified approach to the question, and stuck a big heavy tail on a chicken’s backside to mimic the stature of dinosaurs. And the CoM moved back, just like that. The chickens responded by straightening their legs and swinging their hips more, just as their dinosaur ancestors are hypothesized to do. If you’re interested in reading Gossi’s paper, you can find it here.

The current trend in this kind of research is towards more technical methods; using computer models to digitally reconstruct movement using every muscle, tendon and bone possible. Professor John  Hutchinson and his team are doing exactly that. And their findings unarguably agree with Gossi’s very simple experiment, that the CoM of modern birds has moved forward, and brought with it, the ‘crouched’ stance that we see in the modern day chicken and its relatives.

So, how does the chicken cross the road? Well, as always in science, we can only say how does the chicken NOT cross the road?  Not like a dinosaur (Fig. 2…not to scale!).

Image Source: Science magazine
Image Source: Science magazine

And, if you’re curious, you can check out this newly discovered dinosaur now termed ‘the chicken from hell’.

The Wakatobi Flowerpecker: the reclassification of a bird species and why it matters

Wakatobi Flowerpecker - Male

I posted previously about my PhD research studying bird populations from the tropical and biodiversity-rich region of Sulawesi, Indonesia. I am happy to announce that the first paper as part of this research has just been published in the open access journal PLOS ONE. To read the full paper for free, click here. This work is a collaborative effort from staff in the Department of Zoology in Trinity College Dublin and Haluoleo University in Sulawesi. Here, I’d like to discuss the wider importance of the findings of this study.

My current research focuses on bird populations from peninsular South-east Sulawesi and the nearby Wakatobi Islands. The main focus of this paper was to reassess the taxonomic status of a population of birds from the Wakatobi Islands (i.e. whether these birds represent a species or subspecies). The birds in question belong to the flowerpecker family (Dicaeidae); a group of small and colourful, arboreal passerines found from Southeast Asia to Australia. The Wakatobi birds were originally described as a separate species (Dicaeum kuehni) from those on mainland Sulawesi by the renowned avian taxonomist Ernst J. Hartert. However, for reasons that remain unclear in the literature, the Wakatobi birds were later reclassified as a subspecies of the Grey-sided Flowerpecker (Dicaeum celebicum) from mainland Sulawesi. Therefore we decided the Wakatobi populations were deserving of reassessment. From comparisons of plumage and morphology (that is, the measurement of various features such as a bird’s wing and bill), as well as estimates of genetic divergence and phylogenetic relationships between Wakatobi and Sulawesi populations, our results suggest the Wakatobi birds deserve to be recognised as a distinct species. We have therefore recommended the Wakatobi populations be reclassified as Dicaeum kuehni, a species found only on the Wakatobi archipelago and put forward the common name ‘Wakatobi Flowerpecker’.  For more detailed methods and results check out the paper.

“So what?”, you might say. Well, despite centuries of work from naturalists aiming to estimate the number of different species that exist or have existed on Earth (be they animal, plant, fungus, bacteria, etc) and further understand their evolutionary relationships, we still have a lot to learn! Therefore, this research adds another tiny piece to this enormous and incomplete jigsaw. Through a greater understanding of life on Earth we can attempt to answer some of the great philosophical questions, such as ‘Where and how did life start?’; ‘How and why do new species appear?’;  ‘Why has life evolved to become as it is today?’; and ‘How have we, as humans, come to be?’. Anyway, let’s be honest, who doesn’t enjoy learning of a recently discovered species or simply one they haven’t heard of before (be they as cute as the recently discovered olinguito or as frighteningly ugly as the goblin shark)? But the endeavour to discover species and classify and quantify the diversity on life on Earth brings us much more than entertainment and endless fascination, it also has very practical applications. Data on the distribution and conservation status of species are one of the major sources of information used to inform conservation policy. Therefore, as we are in the midst of an extinction crisis, it is vital that these data are accurate.

In order to maximise our understanding biodiversity, particularly in the remote and poorly known Sulawesi region of Indonesia, we require multi-disciplinary research. For example, take a look at Figure 1 below. On the left are a male (above) and a female (below) Grey-sided Flowerpecker from mainland Sulawesi. On the right are a male (above) and a female (below) Wakatobi Flowerpecker. They look very similar, right? This is true. However there are subtle but consistent differences in plumage between the species (again, see the paper for more info on this). Without the collection of detailed morphological data and the generation of genetic sequences, we may have incorrectly concluded that these make up just one species, when in fact they are morphologically distinct, reproductively isolated and genetically very different. This demonstrates the need for modern research, not just in Sulawesi, but globally, to employ integrative research, combining traditional comparisons of colour, size and shape with modern genetic and phylogenetic analyses.

Figure 1. Plumage comparisons-p18pjcggcs1dgo1ulm1sor9s214bc
Figure 1. A comparison of plumage characteristics between male (top row) and female (bottom row) Grey-sided Flowerpeckers (left) and Wakatobi Flowerpeckers (right).

Despite the knowledge that the Sulawesi region is home to a large number of remarkable birds that are found nowhere else in the world, it has remained relatively poorly studied. Furthermore, there has been a lack of integrative ornithological research in the area and very little genetic sampling. Therefore, it is likely that avian species richness for the Sulawesi region is underestimated and that numerous bird species are awaiting description. On top of this, Sulawesi’s biodiversity is facing major threats from a rapidly expanding human population and mass habitat destruction, among other things. Unless we can encourage more multi-disciplinary research within the region, we will likely fail to recognise evolutionarily distinct lineages and run the risk of losing them forever.

Our current findings inspire many further questions. For example, why have the flowerpeckers on the Wakatobi islands become so different to their close relatives on mainland Sulawesi? In other words, what are the evolutionary pressures that have driven the divergence of the Wakatobi Flowerpeckers? By investigating these questions, we hope to learn more about the evolutionary processes of speciation and adaptation to living on islands. As the Wakatobi Flowerpecker is found only on the Wakatobi Islands, the protection status afforded to the islands may require reassessment. Furthermore, considering one unique bird species has evolved on the Wakatobi, could there be more? Watch this space.

Author and Images:  Seán Kelly, kellys17[at]tcd.ie, @seankelly999

Are men really better than women?

When you imagine a scientist, what do you imagine? The first image that I see, despite never having seen it in real life (thankfully!), is the traditional “mad scientist”. The white lab-coat, crazy hair, glasses or goggles, holding a flask or test tube containing some dangerous-looking substance. This scientist is, inevitably, male (and white, but that’s a subject for another day).

Mad scientist

The lack of women in science has become a cause for concern for many people. Discussions of how to fix the “leaky pipe”, where female students are lost at a disproportionately higher rate than their male colleagues at postgraduate level and beyond, have become increasingly frequent. Some of these potential fixes were discussed a couple of years ago here on this blog.

But why do we want more women in science? Surely science, being so objective and rational, has little need for political correctness? If there aren’t many women in science then that’s just an indication that they aren’t smart enough or don’t want to put in the work required to reach high academic positions and by trying to increase the numbers artificially we’ll end up with poorer science and the advancement of knowledge will slow to a stand-still.

This may sound like hyperbole but it’s not far off what has been argued. Larry Summers, then-president of Harvard, argued that women were less intelligent than men due to genetic differences and that childcare burdens meant women weren’t willing to put in the long hours necessary to advance their careers. The lack of science to support these statements is disturbing from someone in his position. The genetic differences are negligible and the experiences of transgender people show that people’s assessment of intelligence is often linked to their perception of gender. As to women shouldering the burden of childcare, well, personally I see this as an opportunity to make this burden more equal, rather than punish the women for having the temerity to reproduce (a man was involved in this reproduction as well, after all).

Getting back to the question, why does it matter if science is largely dominated by men? A scientist is a scientist and their gender shouldn’t matter. While it’s unfortunate that women have not been welcomed into science, it hasn’t affected what science has been done. Has it? Well, chances are, it has.

A recent paper published in PloS Biology looked at the studies into genital evolution. The paper, by Ah-King and colleagues found a distinct bias in the focus of these studies towards male genitalia and away from female genitalia that was not explained by any obvious cause such as ease of study or taxonomy. Given the tenor of this piece you’ll be forgiven for thinking that I’m going to say “but when they looked at the sex of the researcher they found that women studied vaginas while men studied penises and as there’s more men in science that’s caused the bias” but the researchers looked at this and found that men and women had a similar bias towards researching male genitals.

Waterfowl genitalia
Waterfowl genitalia. Modified from Brennan et al., 2007, PLoS One

So does this mean that this study actually goes against my hypothesis that the sex of the researcher matters? I don’t think so. This study can’t be taken in isolation, it must be taken in context. The context is that ever since Darwin, males have been perceived as the dominant sex and the ones driving sexual evolution with the females as little more than passive receivers of sperm. While this is now known not to be the case, such attitudes take a long time to die. The researchers discuss this explicitly:

“. . . [we] suggest that the bias reflects now outdated assumptions about the unimportance of, or lack of, variation in female genitalia in sexual evolutionary dynamics.” (p6).

This highlights the problem, not only of not having women in science now, but of having a historical absence of women. As the subject has historically been studied and taught by men to men, many unfounded beliefs have taken hold. The belief that males are inherently more interesting to study is just one example of this. These beliefs become so pervasive that everyone believes them, and may explain why women have the same bias towards studying male genitalia that men have.

The lack of women in science means that unfounded beliefs such as this go unchallenged for so long that they become core tenets of disciplines and trying to overturn them takes immense effort. It allows scientists to say that women are less intelligent than men and use their absence as evidence, in the same way that some use the absence of minorities as indications of their intelligence, ignoring the systematic biases that prevent them from attaining a position of authority within their field, or even entering it in the first place. Neil Degrasse Tyson beautifully summed up the barriers to entry presented to women and minorities, none of which are to do with intelligence and all are to do with cultural expectations and the resistance experienced when you try to surmount those expectations.

Increasing diversity has innumerable benefits and no real downsides (though it may have perceived ones, particularly for those whose positions of authority are being challenged). In a recent NERD club we discussed the benefits of mobility, which included being exposed to new ideas and new ways of doing things in different departments. This exposure to new ideas can also come through increasing the pool of people from which scientists are drawn. When most of your scientists are male, they will be, on average, more interested in male genitalia than female. When most of your scientists are from the western hemisphere, the majority of the research will be biased towards those countries. Increasing diversity increases the field of interests scientists have and will actually accelerate our scientific knowledge. Diversity makes better science.

Author: Sarah Hearne, hearnes[at]tcd.ie, @SarahVHearne

Image: Wikicommons