Happy New Year!

I hereby wish all my co-workers (students, PhD-students, postdocs and colleagues) a Happy New Year 2011! I certainly hope that the new year will be as succesful as the previous was, for many of us. Apart from several good publications in excellent journals (BMC Evolutionary Biology, Evolution, J. Evol. Biol., TREE to mention only a few) I would also like to highlight some other great highlights (to me personally):

1. Kristina Karlsson succesfully defended her PhD in November and have already published most of her thesis-papers. Well done!

2. Fabrice Eroukhmanoff got a postdoctoral 2-year grant from The Swedish Research Council (VR) to go to Norway (Oslo University) and work with Glenn-Pether Saethre and Thomas F. Hansen.

3. Machteld Verzijden found out, just before Christmas, that she will stay in our lab for 2-3 more years, due a postdoctoral scholarship from the Wenner-Gren Foundations.

4. Former postdoc Shawn Kuchta got a faculty position at Ohio University (Athens, USA), and started up his new lab from the beginning of September 2010. Sophia Engel visited him during November, and I will myself go there for a visit in April 2011.

Needless to say: I am proud to work with such a group of excellent and dedicated scientists as you guys! Although academic life is stressful and we compete (like all other groups) for grants and to get our papers published in good journals, I think we are doing remarkably well, as a lab and as a group. I think this is because we regularly meet and discuss science - in a friendly and cooperative atmosphere. This is the key to sucess - much more than large research grants. I hope we can continue along this succesful path for many years to come.

As for myself, I will now leave for South Africa (well, tomorrow!), and will be back in the last week of January. Until then; enjoy this picture of a Greater Collared Sunbird, photographed in the Eastern Cape Province in South Africa in April this year. My overly ambitious daughter My (who is soon a professional blogger and expert in HTML-programming, by the way), has started up a new photo blog, where she wants us both to upload our photos during the trip to South Africa. You can find it here.

I am not sure I will allocate that much time as my daughter expects me to, as I want to stay away from the internet for a while, when enjoying field work, good wine, birds and wildlife. But keep following this other blog, perhaps I will change my mind :).

How we are evolving and more on the "missing heritability" problem

Although I suggested  we should skip articles for next lab-meeting (Wednesday 22 December), I changed my mind after finding a couple of interesting papers in the popular science magazine Scientific American. Both deal with human evolution and human genetics, and should be an easy read, and are of much principal interest, also to us.

The first one raises the question "How we are evolving" and it discusses the recent recent data obtained from "Next-generation sequencing" that have elucidated the evolutionary history of coding genes in Homo sapiens. It turns out that so-called "selective sweeps" are quite unusual in our genome, i. e. alleles that have quickly increased in frequency in response to local selection pressures and in local environments. Thus, the case of the recent demonstrated selective sweep in the genes affecting haemoglobin production when humans invaded the Tibetan Plateau that we discussed earlier this year, are atypical, and do not seem to be the norm (according to the article in Scientific American).

Instead, it appears that the global distribution of human coding genes more reflects recent migration histories: genes that increased in frequency at a certain place were then carried along to new places as human colonized the Earth. This implies that selective sweeps are rare, and they mainly happen when there is strong and sustained selection that is consistent over relatively long time at a given place. This implies that selection might in general be relative weak, in humans at least. Perhaps humans are able to adapt (culturally) and counteract selection pressures by cultural adaptations, such as clothing, food habits etc., which weakens natural selection in many environments?

The other article in Scientific American deals with the so-called "missing heritability"-problem, i. e. the uncomfortable facts that there are very few genes explaining a substantial amount of variation in diseases. Thus, most large-effect genes are quite rare in the populations, whereas those genes that are common explain only a tiny fraction (in the order of a few percent) of the disease-related variation. This has caused despair among molecular biologists and biomedical researchers, since the huge amount of sequencing data has not solved many of Homo sapiens biomedical problems (contrary to promises in the most enthusiastic heydays of genome sequencing). In spite of thousands of variable SNP:s ("single-nucleotide polymorphisms"), only a few percent of the total amount of variation in human phenotypic traits are explained by these molecular markers. This can either be interpreted as a great disappointment (in relation to promises), a complete failure for molecular biology or a great triumph of quantitative genetics, but as usual, the questions that are raised by these findings might be more interesting than the exact answers. The solution? Well, certainly not to sequence more or try to obtain more SNP:s, but rather to think harder (surprisingly, an underutilized strategy in much of today's science!).

The two articles can be found here and here, and I think you will enjoy both, as they are relatively easy read. Let's have a brief and informal discussion about these papers on Wednesday, after we've had some glögg!

Soon Christmas and last lab-meeting for this year on December 22 2010

Wednesday 22 will be the last lab-meeting for this year before Christmas, and before I leave for South Africa. I was thinking we should skip a paper this time, and just discuss some general issues and any remaining practicalities before the winter break. I will bring "glögg" (both with and without alcohol!), if somebody else could volunteer to bring "lussekatter" and/or pepparkakor.

Hope to see you in "Darwin" then on December 22. Same time as usual: 10.15.

Interesting blog about "Eco-evolutionary dynamics" by Andrew Hendry's lab

Those of you have met Andrew Hendry before, either in Vienna during the "Speciation"-meeting last week, or last year when he was the external opponent on the PhD-thesis by Fabrice Eroukhmanoff, might enjoy this blog from his research laboratory. His lab seem to have a similar attitude as ours when it comes to public outreach and using social media, which is nice. A general theme of their blog is "Eco-evolutionary dynamics", which fits well with the kind of research Hendry et al. have been pursuing in recent years, using sticklebacks, guppies and Galápagos finches as study organisms. Enjoy!

Greetings from "Speciation-meeting" in Vienna!

Together with several other colleagues from Lund, Sweden and other countries, our lab was well-represented at the first European Speciation Conference, organized by the Institute for Advanced System Analysis (IIASA) in Vienna (Austria). This three-day conference has gathered a number of researchers working on the problems of speciation, both theoretically and empirically. A list of talks from the conference can be found here.  

The first evening of the conference, we enjoyed nice Austrian food (LOTS of meat!) and good wine, and of course the company of many of our colleagues. On the picture above you can see how happy we are after tasting some great wine. From left to right you see Anna Runemark (Lund University), Fredrik Haas (currently at Oslo University), Erik Svensson (Lund University), Andrew Hendry (McGill University, Canada), Anna Qvarnström (Uppsala University) and Jörgen Ripa (Lund University).Although this time there was a Scandinavian bias at the table, we have also of course interacted and entertained ourselves with some other great colleagues, such as Maria Servedio as well as former McArthur student and legendary ecologist Mike Rosenzweig.

 Personally, I mostly enjoyed the talk by Daniel Bolnick (University of Texas at Austin), about the rarity of sympatric speciation in sticklebacks, which was somewhat heretical in a conference that has been so dominated by the "Adaptive Dynamics"-school, led by Ulf Dieckmann at IIASA, where the importance of sympatric speciation has been vastly exaggerated, in relation to its real importance in natural populations (in my personal opinion). If sympatric speciation was as common as these models of "evolutionary branching" indicate, there would essentially be a new species on every twig of a bush, which there clearly isn't. This very fact in itself suggests (at least to me) that constraints on sympatric speciation are likely to operate and be important, and that the asexual modelling approach in the adaptive dynamics school has underestimated the severity of recombination.

As a primarily empirically oriented evolutionary biologist, I see a major weakness of the Adaptive Dynamics-school in that their models are only weakly connected to empirical work and the parameters they include in their models are not as natural to estimate as the classical and well-established estimates typically  used by field evolutionary biologists that are derived from quantitative genetics (i. e. selection coefficients). In the absence of such transparent models with parameters defined in an empirically meaningful way, the jury is still out whether adaptive and sympatric speciation is really important in nature, or whether it is mainly a phenomena that gains more attention from theoreticians than it deserves from an empirical point of view of practicing naturalists and field biologists.

Our learning paper is covered by German radio

Our recent paper on learned mate preferences in Calopteryx splendens females has now also been covered in German Radio. An excerpt from an interview Joachim Budde made with me in the German Radio channel Deutschland Funk is available here, unfortunately only in German. Enjoy!

lab meeting December 8

For this week's labmeeting I have chosen a review on the evolution of sexual dimorphism in Lepidoptera, by Cerise Allen, Bas Zwaan and Paul Brakefield (all of whom I know from Leiden, though none of them are there anymore). In this paper they review the evidence for the relative contributions of natural and sexual selection to the evolution of sexual dimorphism.
Though none of us work on Lepidoptera, we do all work on sexual dimorphism in one way or another, so in that sense it's right on topic for us!

You can download this paper here.
The abstract is below some of my own pictures from Lepidoptera from the American continent.
Enjoy!

Abstract:
Evolution of Sexual Dimorphism in the Lepidoptera

Among the animals, the Lepidoptera (moths and butterflies) are second only to beetles in number of described species and are known for their striking intra- and interspecific diversity. Within species, sexual dimorphism is a source of variation in life history (e.g., sexual size dimorphism and protandry), morphology (e.g., wing shape and color pattern), and behavior (e.g., chemical and visual signaling). Sexual selection and mating systems have been considered the primary forces driving the evolution of sexual dimorphism in the Lepidoptera, and alternative hypotheses have been neglected. Here, we examine opportunities for sexual selection, natural selection, and the interplay between the two forces in the evolution of sexual differences in the moths and butterflies. Our primary goal is to identify mechanisms that either facilitate or constrain the evolution of sexual dimorphism, rather than to resolve any perceived controversy between hypotheses that may not be mutually exclusive.

Seminar by Nina Wedell on selfish genetic elements and sexual selection and PhD-thesis defency by Kristina Karlsson

This week our department will be visited by Professor Nina Wedell (Exeter University, UK), who will act as an external faculty opponent on the thesis of Kristina Karlsson Green, on Friday November 26 (09.30, "Blue Hall", Ecology Building).


Nina Wedell is well-known for her research on sperm competition, sexual selection and mating system evolution in insects. You can read more about her research here, and here you can find some of her publications. Here is an article about Ninas recent research on the evolutionary consequences and benefits of female promiscuity.


Nina Wedell will arrive to our department already on Thursday (November 25), and will present a research seminar at 14.00 entitled: 


"Selfish genetic elements and sexual selection"


This talk is co-arranged with The Research School in Genomic Ecology (GENECO), and there will also be another talk by Sören Molin the same afternoon and the same place (Lecture Hall, Biology Building, Sölvegatan 35 A), but at 15.15. Note that both these talks do not take place in the "Blue Hall", but in a separate building ("The Biology Building").

Papers for labmeeting on November 24: genomics and sex ratio evolution

This Wednesday, we will discuss two short papers, one in Nature Genetics and the other one in Nature. They are both very short, but should make interesting reads. The first paper was suggested by Bengt Hansson, and is an example of how the sequencing of entire genomes can shed light over local adaptation, in this case of the plant Arabdopsis lyrata to serpentine soils. You can download that paper here. The second paper is an example of how climatic factors can drive population divergence in sex determination systems, in this case over an altitudinal gradient of an Australian lizard species. You can download that paper here. Abstracts of both papers are provided below.

I hope you enjoy these papers and that we will have a good discussion. Time and place as usual: "Darwin" at 10.15 (Wednesday November 24). Fika volunteers are encouraged to step forward.

Population resequencing reveals local adaptation of Arabidopsis lyrata to serpentine soils  

Thomas L Turner, Elizabeth C Bourne, Eric J Von Wettberg, Tina T Hu & Sergey V Nuzhdin

Nature Genetics 42: 260–263 (2010)

DOI: doi:10.1038/ng.515

A powerful way to map functional genomic variation and reveal the genetic basis of local adaptation is to associate allele frequency across the genome with environmental conditions. Serpentine soils, characterized by high heavy-metal content and low calcium-to-magnesium ratios, are a classic context for studying adaptation of plants to local soil conditions. To investigate whether Arabidopsis lyrata is locally adapted to serpentine soil, and to map the polymorphisms responsible for such adaptation, we pooled DNA from individuals from serpentine and nonserpentine soils and sequenced each 'gene pool' with the Illumina Genome Analyzer. The polymorphisms that are most strongly associated with soil type are enriched at heavy-metal detoxification and calcium and magnesium transport loci, providing numerous candidate mutations for serpentine adaptation. Sequencing of three candidate loci in the European subspecies of A. lyrata indicates parallel differentiation of the same polymorphism at one locus, confirming ecological adaptation, and different polymorphisms at two other loci, which may indicate convergent evolution.

Climate-driven population divergence in sex-determining systems

Ido Pen, Tobias Uller, Barbara Feldmeyer, Anna Harts, Geoffrey M. While & Erik Wapstra

Nature 468: 436–438 (18 November 2010)

DOI: doi:10.1038/nature09512

Sex determination is a fundamental biological process, yet its mechanisms are remarkably diverse. In vertebrates, sex can be determined by inherited genetic factors or by the temperature experienced during embryonic development. However, the evolutionary causes of this diversity remain unknown. Here we show that live-bearing lizards at different climatic extremes of the species’ distribution differ in their sex-determining mechanisms, with temperature-dependent sex determination in lowlands and genotypic sex determination in highlands. A theoretical model parameterized with field data accurately predicts this divergence in sex-determining systems and the consequence thereof for variation in cohort sex ratios among years. Furthermore, we show that divergent natural selection on sex determination across altitudes is caused by climatic effects on lizard life history and variation in the magnitude of between-year temperature fluctuations. Our results establish an adaptive explanation for intra-specific divergence in sex-determining systems driven by phenotypic plasticity and ecological selection, thereby providing a unifying framework for integrating the developmental, ecological and evolutionary basis for variation in vertebrate sex determination.

evoecogeomorphometrical fun

Hello from the wilds of Athens, Ohio! As Sophia said, we're geeking out on the study of shape. Such analyses receive less attention than they should, but think about it: everything has shape! Its a serious matter. As Houle (2010 PNAS) noted, we would benefit greatly from a revolution in "phenomics" to compliment recent advances in genomics.

Here's one of the papers Sophia and I read, which can be found on Dean Adams' web page:

Adams, D. & M. L. Collyer. 2009. A general framework for the analysis of phenotypic trajectories in evolutionary studies. Evolution 63: 1143-1154.

This paper is simply an analytical technique, but it is broadly applicable to all sorts of questions in biology, and my brain was exploding with ideas as I read it. While you are checking out Adams' web page, read a few other papers, too -- he's one of my favorite scientists.

Speaking of favorite scientists: it turns out the Donald Miles in the Department of Biological Sciences here at Ohio University is also interested in geometric morphometrics. We recently discussed the possibility of forming a GMM reading group this winter, or even working through the book "Morphometrics with R" (Julian Claude, 2008), which is valuable but not easy. These ideas are preliminary, and it may or may not happen exactly this winter (it will happen, though) -- if you'd like to join in remotely (Skype meetings?) shoot me an email.

Working here with Sophia has been an absolute blast! Y'all are very lucky to have her among your ranks!!! In addition, I'm very excited to have the opportunity to contribute in a small way to the ongoing studies of Calopteryx splendens, which I view as a system with extraordinary potential. Together, Sophia and I have studied GMM, made chili, eaten burritos at the Burrito Buggy, cruised around in my 1983 VW bus (her name is Betsy), and drank quite a few beers and glasses of wine. We also found the salamander shown above (picture stolen off of Amphibiaweb). LIfe is good.

Peace.

Hi from Athens.

I’m having a good time here, filled with damselfly wings and the theory of Geometric Morphometrics during the daytime, and socializing and beers in the evenings. Shawn is part of a very lively and nice department!

The first week spoiled me with balmy summer temperatures (well, almost) and a spontaneous multiplication of my salamander species counts! There are gorgeous species to be found here, my favorite is the Red Salamander (Pseudotriton ruber) because of its beautiful coloration, and it is well worth strolling through the beautiful forest and looking under logs and stones for a (rare, I’ve been told) glimpse of it.

Our literature seminars are usually attended just by Shawn and me, but we gladly share our reading list in the hope to spark your interest in morphology and the statistical methods for its analysis:

The study of Dean C. Adams (Evolutionary Biology 2010, 10:72) is a nice real-world example of character displacement in salamanders driven by competitive selection in sympatric populations.

The underlying theoretical framework for such studies is described in an earlier paper by the same author (Dean C. Adams and Michael L. Collyer (2009) Evolution 63-5: 1143-1154), and historical overview and review of available methods for shape analysis can be found in Adams et al. 2004 (Ital. J. Zool. 71: 5-16. Another review paper by Christian P. Klingenberg (Nature 2010, Vol 11, 623-635) approaches the topic from an evo-devo perspective.

Dreaming of partial warps in Procrustes space…

Sophia

Recently we have published two studies based on the isopod system of Asellus aquatics. This species occurs in two ecotypes, which resides in different habitats. As the ecotypes are present in several Swedish lakes, this system has been studied in depth with regard to parallel evolution. Our new articles address differences in mating behavior between the ecotypes. As other crustaceans, A. aquaticus exhibits precopulatory mate guarding where the male captures a female before she is receptive and carries her beneath him until she is ready to mate. This behavior is target for sexual conflict in several isopods as the optimal initiation of pairbonding may differ between the sexes.

One of our articles, published in the latest number of Journal of Evolutionary Biology, deals with differences between the ecotypes in mate guarding duration, but also in differences in female survival and offspring production. Among other things, we found a pattern of parallel evolution in these traits. The other article, published in open access journal PLoS ONE, deals with differences in mating propensity between the ecotypes and how this is affected by demographic factors. Here, we found that the novel ecotype seem to have evolved a plastic behavior as response to sex ratio, in contrast to the ancestral ecotype.

You could find both abstracts below, and both articles are included in Kristina Karlsson Green’s thesis that will be defended on next Friday.

Parallel divergence in mate guarding behaviour following colonization of a novel habitat

K. Karlsson, F. Eroukhmanoff, R. Härdling & E.I. Svensson

Abstract

Ecological factors can have profound effects on mating system and mating behaviour. We investigated the effect of altered ecological conditions, following colonization of a novel habitat, on precopulatory mate guarding in a freshwater isopod (Asellus aquaticus). This isopod occurs in two different ecotypes, which coexist within several different lakes in Sweden but which utilize different habitats. These ecotypes have rapidly (ca. 40 generations) diverged in parallel among lakes in several phenotypic characters, presumably as a response to different predatory pressures. Here, we demonstrate that also mate guarding characteristics have diverged in parallel between the ecotypes in different lakes. This is one of the few studies reporting parallel evolution of mating behaviour. Furthermore, our results also indicate a potential sexual conflict, as the length of mate guarding appears to lower components of female fitness. We discuss how novel environments might have strong and rapid effects on mate guarding dynamics and mating behaviour.

Phenotypic Plasticity in Response to the Social Environment: Effects of Density and Sex Ratio on Mating Behaviour Following Ecotype Divergence

Kristina Karlsson^*, Fabrice Eroukhmanoff, Erik I. Svensson

Abstract

The ability to express phenotypically plastic responses to environmental cues might be adaptive in changing environments. We studied phenotypic plasticity in mating behaviour as a response to population density and adult sex ratio in a freshwater isopod (Asellus aquaticus). A. aquaticus has recently diverged into two distinct ecotypes, inhabiting different lake habitats (reed Phragmites australis and stonewort Chara tomentosa, respectively). In field surveys, we found that these habitats differ markedly in isopod population densities and adult sex ratios. These spatially and temporally demographic differences are likely to affect mating behaviour. We performed behavioural experiments using animals from both the ancestral ecotype (‘‘reed’’ isopods) and from the novel ecotype (‘‘stonewort’’ isopods) population. We found that neither ecotype adjusted their behaviour in response to population density. However, the reed ecotype had a higher intrinsic mating propensity across densities. In contrast to the effects of density, we found ecotype differences in plasticity in response to sex ratio. The stonewort ecotype show pronounced phenotypic plasticity in mating propensity to adult sex ratio, whereas the reed ecotype showed a more canalised behaviour with respect to this demographic factor. We suggest that the lower overall mating propensity and the phenotypic plasticity in response to sex ratio have evolved in the novel stonewort ecotype following invasion of the novel habitat. Plasticity in mating behaviour may in turn have effects on the direction and intensity of sexual selection in the stonewort habitat, which may fuel further ecotype divergence.

Journal cover in "Evolution" and the role of learned mate preferences in population divergence

Most of you have already seen this - but I post it again in case somebody missed it. We've got the journal cover in the November 2010 issue of Evolution, featuring our article about learned mate preferences in the banded demoiselle (Calopteryx splendens). This paper has also been highlighted by the popular science site Science Daily, and it will also be covered in a popular science radio programme in Germany, since I was recently interviewed about the study by a journalist from our southern neighboring country.

Apart from our own article, the same issue contains a number of interesting other articles about sexual selection, most notably Richard Prums paper about null models in sexual selection in which he argues that the Lande-Kirkpatrick (NK)-model as the most appropriate such null model, a paper we discussed at the lab-meeting last week. Here is the title and abstract of our own paper:


A ROLE FOR LEARNING IN POPULATION DIVERGENCE OF MATE PREFERENCES  


Erik I. Svensson, Fabrice Eroukhmanoff, Kristina Karlsson, Anna Runemark & Anders Brodin

Article first published online: 13 JUL 2010

DOI: 10.1111/j.1558-5646.2010.01085.x

Learning and other forms of phenotypic plasticity have been suggested to enhance population divergence. Mate preferences can develop by learning, and species recognition might not be entirely genetic. We present data on female mate preferences of the banded demoiselle (Calopteryx splendens) that suggest a role for learning in population divergence and species recognition. Populations of this species are either allopatric or sympatric with a phenotypically similar congener (C. virgo). These two species differ mainly in the amount of wing melanization in males, and wing patches thus mediate sexual isolation. In sympatry, sexually experienced females discriminate against large melanin wing patches in heterospecific males. In contrast, in allopatric populations within the same geographic region, females show positive (“open-ended”) preferences for such large wing patches. Virgin C. splendens females do not discriminate against heterospecific males. Moreover, physical exposure experiments of such virgin females to con- or hetero-specific males significantly influences their subsequent mate preferences. Species recognition is thus not entirely genetic and it is partly influenced by interactions with mates. Learning causes pronounced population divergence in mate preferences between these weakly genetically differentiated populations, and results in a highly divergent pattern of species recognition at a small geographic scale.

Null models in sexual selection

For next week's labmeeting I suggest to read the paper by Richard Prum in the most recent issue of Evolution about making the Lande-Kirkpatric model of sexual selection the null model, kind of like a Hardy-Weinberg equilibrium. The abstract is posted below. I saw Richard Prum give a presentation at the ISBE this last month, and I really liked his talk. He does not propose any new models for sexual selection, but rather gives ideas for a new perspective on the existing models & the data. Good food for thought, right?

And, to liven up the blog a bit here are some pictures of odonates from my recent trip to Borneo. Enjoy! (both the paper and the pictures).

Abstract:

The Lande-Kirkpatrick mechanism is the null model of evolution by intersexual selection: implications for meaning, honesty, and design in intersexual signals.

The Fisher-inspired, arbitrary intersexual selection models of Lande (1981) and Kirkpatrick (1982), including both stable and unstable equilibrium conditions, provide the appropriate null model for the evolution of traits and preferences by intersexual selection. Like the Hardy–Weinberg equilibrium, the Lande–Kirkpatrick (LK) mechanism arises as an intrinsic consequence of genetic variation in trait and preference in the absence of other evolutionary forces. The LK mechanism is equivalent to other intersexual selection mechanisms in the absence of additional selection on preference and with additional trait-viability and preference-viability correlations equal to zero. The LK null model predicts the evolution of arbitrary display traits that are neither honest nor dishonest, indicate nothing other than mating availability, and lack any meaning or design other than their potential to correspond to mating preferences. The current standard for demonstrating an arbitrary trait is impossible to meet because it requires proof of the null hypothesis. The LK null model makes distinct predictions about the evolvability of traits and preferences. Examples of recent intersexual selection research document the confirmationist pitfalls of lacking a null model. Incorporation of the LK null into intersexual selection will contribute to serious examination of the extent to which natural selection on preferences shapes signals.

New thesis from the lab by Kristina Karlsson, nailing and next lab-meeting

Probably, the proudest moment in the life of PhD-student advisors is when their students has finished his/her thesis. This has now happened once again in our lab, and I am of course extremely happy that my fourth PhD-student Kristina Karlsson has now gotten her PhD-thesis back from the printer. Before Tina, Jessica Abbott (2006), Tom Gosden (2008) and Fabrice Eroukhmanoff (2009) has previously succesfully finished their theses, and I am of course happy to soon be able to kall Tina Dr. Karlsson.

The second proudest moment in the life of the PhD-student advisors is usually the thesis defence. This will take place on Friday November 26 2010 in the "Blue Hall" (Ecology Building). The external opponent on Tinas thesis will be Professor Nina Wedell (Exeter University, UK), and the thesis defence will start at 09.30.

Prof. Wedell will also give an invited research seminar the day before Tinas thesis dissertation (November 25) with the title: "Sexual selection and selfish genetic elements". This talk will take place in the "Red Room" (Ecology Building) at 14.00 on November 25 2010. Needless to say, both Prof. Wedell's talk on November 25 as well as the dissertation ceremony on November 26 are open to the general public and everybody who is interested.

Tina will "nail" her thesis on the "Oak" outside the Biology Library next Wednesday (November 10, 2010) at 15.00. Drinks will be served after this ceremony, and again, it is open to anyone who wish to attend. The same day, our regular lab-meeting will take place as usual (10.15-12.00 in "Darwin"). Anna Runemark will send out a manuscript of ours about sexual selection in mainland and island populations, with the hope to get some input and criticisms. If you do not receive this manuscript, please send Anna an e-mail and she can send you a copy (anna.runemark@zooekol.lu.se). Fika volunteers are particularly welcome to this meeting.

update: new time for tomorrow's lab meeting: 11.00

Tomorrow's labmeeting will be one hour later than usual, at 11.00, because there is an interesting talk by Niels Dingemanse from the Max Planck Institute for Ornithology in the limnology group at 10.00. Niels is one of the leading researchers on the theme of animal personality, and his talk is likely to be interesting for anyone working on the evolution of behaviour. Here is a link to his website.

Can phylogenetic methods from evolutionary biology inform us about how societies evolve?

This coming lab-meeting (Wednesday 27 October), I was thinking that we should discuss if and how methods from evolutionary biology can elucidate problems studied by political scientists: the rise and fall of societies. There is an interesting article published in Nature, where the authors used phylogenetic methods to investigate if societies evolved towards more complexity (or not). The study was performed on a set of societies in South-East Asia and in the Pacific.  

Evolutionary biologist and community ecologist Jared Diamond has an interesting perspective about the study. Read both the comment by Diamond and the original article so that we can have an interesting discussion on Wednesday. Time and place as usual: "Darwin" at 10.15. Below is the abstract and title of the original paper:

Rise and fall of political complexity in island South-East Asia and the Pacific  

Thomas E. Currie,Simon J. Greenhill, Russell D. Gray, Toshikazu Hasegawa & Ruth Mace 

There is disagreement about whether human political evolution has proceeded through a sequence of incremental increases in complexity, or whether larger, non-sequential increases have occurred. The extent to which societies have decreased in complexity is also unclear. These debates have continued largely in the absence of rigorous, quantitative tests. We evaluated six competing models of political evolution in Austronesian-speaking societies using phylogenetic methods. Here we show that in the best-fitting model political complexity rises and falls in a sequence of small steps. This is closely followed by another model in which increases are sequential but decreases can be either sequential or in bigger drops. The results indicate that large, non-sequential jumps in political complexity have not occurred during the evolutionary history of these societies. This suggests that, despite the numerous contingent pathways of human history, there are regularities in cultural evolution that can be detected using computational phylogenetic methods.

Remembering the summer: field work with damselflies in Skåne

 

Winter is approaching fast, and what could be better then than to try to remember the past beatiful summer for as long as possible?Varm summers means field work with insects, at least for some of us. This was also the case for myself, CAnMove postdoc Sophia Engel and a number of other students and postdocs working with field studies of calopterygid damselflies. Here is a nice movie about CAnMove-related field work from Lund University's Youtube-channel. This movie contains an interview with Sophia and myself, where we explain what kind of experiments we did, and why. Unfortunately, this movie is in Swedish, not English, but at least you can enjoy the pictures!

Basically, we have quantified flight speeds of individually marked damselflies of two species (Calopteryx virgo and C. splendens), and we relate this performance-trait to wing morphology (shape), longevity in the field and mating success (sexual selection). A key player in this system is an enigmatic avian predator which kills these insects: The white wagtail (Motacilla alba), which also appears in the movie. The ornithologists among you readers will hopefully also realise how fascinating this insect system actually is, since it obviously also involves a bird! A key goal of ours is to link morphology to performance and fitness, and combine flight speed estimates with data on morphology and fitness. Such studies are rarely possible to perform, particularly not in natural populations of insects, so we are quite excited about the results that will hopefully come out from this work.

If the movie above does not work, you could follow this link instead. Enjoy! And go back and watch this movie whenever you miss the summer...

Island biology and morphological divergence of the Skyros wall lizard Podarcis gaigeae: a combined role for local selection and genetic drift on color morph frequency divergence?

 

















We have recently published a paper on evolutionary processes in isolated islet populations of the Skyros wall lizard, Podarcis gaigeae in BMC Evolutionary Biology. The paper investigates the relationship between neutral genetic divergence and morphological divergence in islet- and mainland populations. The morphological trait we use in the comparisons is throat colour morph, and islet populations show pronounced frequency differences with different morphs being common on different islets. Our data suggests that stochastic forces such as genetic drift and/or founder effects can interact with selection and have an effect even at a morphological level in islet populations with low effective sample sizes. BMC Evolutionary Biology is an open access journal and a link to the paper is found here. The abstract is as follows:

Island biology and morphological divergence of the Skyros wall lizard Podarcis gaigeae: a combined role for local selection and genetic drift on color morph frequency divergence?

Anna Runemark, Bengt Hansson, Panagiotis Pafilis, Efstratios D. Valakos & Erik I. Svensson

Background

Patterns of spatial variation in discrete phenotypic traits can be used to draw inferences about the adaptive significance of traits and evolutionary processes, especially when compared to patterns of neutral genetic variation. Population divergence in adaptive traits such as color morphs can be influenced by both local ecology and stochastic factors such as genetic drift or founder events. Here, we use quantitative color measurements of males and females of Skyros wall lizard, Podarcis gaigeae, to demonstrate that this species is polymorphic with respect to throat color, and the morphs form discrete phenotypic clusters with limited overlap between categories. We use divergence in throat color morph frequencies and compare that to neutral genetic variation to infer the evolutionary processes acting on islet- and mainland populations.

Results

Geographically close islet- and mainland populations of the Skyros wall lizard exhibit strong divergence in throat color morph frequencies. Population variation in throat color morph frequencies between islets was higher than that between mainland populations, and the effective population sizes on the islets were small (N_e:s <>ST) for throat color morph frequencies fell within the neutral F_ST-distribution estimated from microsatellite markers, and genetic drift could thus not be rejected as an explanation for the pattern. Moreover, for both comparisons among mainland-mainland population pairs and between mainland-islet population pairs, morph frequency divergence was significantly correlated with neutral divergence, further pointing to some role for genetic drift in divergence also at the phenotypic level of throat color morphs.

Conclusions

Genetic drift could not be rejected as an explanation for the pattern of population divergence in morph frequencies. In spite of an expected stabilising selection, throat color frequencies diverged in the islet populations. These results suggest that there is an interaction between selection and genetic drift causing divergence even at a phenotypic level in these small, subdivided populations.

Lab-meeting about intralocus sexual conflict and seminar by Jessica Abbott

This week's lab-meeting has been moved to Thursday morning (10.00-12.00) and to the seminar room "Fagus" (third floor above "Darwin"), due to the seminar by outside visitor and former lab-member Jessica Abbott in the same day, in the afternoon (14.00, "Blue Hall").

The theme of Jessica's talk will be intralocus sexual conflict and genetic constraints, and that will also be the theme of our lab-meeting. I was thinking that we should discuss a recent review by Jessica in Proc. R. Soc. Lond. B. about how one can study intralocus sexual conflict in hermaphroditic animals. Hopefully, Jessica will arrive in time to comment on this paper as well, her expected arrival time to the Department is about 11.00.

Before we discuss Jessica's interesting review-paper, we will discuss a manuscript that I and Fabrice Eroukhmanoff have written about population variation in intersexual genetic correlations and sexual dimorphism in aquatic isopods (Asellus aquaticus). We have worked on this manuscript for quite a while and we would be interested in getting some input. The results have clear links to the research topic and interests by Jessica. We will send you out this manuscript in a separate e-mail, hopefully today (Monday). Send me an e-mail if you do not get it (erik.svensson@zooekol.lu.se).

After our lab-meeting in "Fagus", there will be opportunity to go for lunch with Jessica, and at 14.00 her seminar starts in the "Blue Hall" in the Ecology Building, entitled:


"Using sex-limited evolution to detect evolutionary constraints"

You can read more about Jessica's research here, and here you can find a list of past and more recent publications. 

Updated Wednesday-plans for lab-meeting on October 6

On Wednesday, our lab-meeting will start one hour later, at 11.15, as there is an interesting seminar that starts at 10.00 in the Limnology Section's seminar room "Tanken" (first floor). The talk will be given by Dr. Martin Lind, former PhD-student in Umeå in the laboratory of Frank Johansson, and currently a VR-postdoc at Sheffield University (UK). The title of Martins talk is:

"Local adaptation, gene flow, cost and benefits of phenotypic plasticity"

After the seminar, we walk back to the 2nd floor, and start  our regular lab-meeting at 11.15, i. e. one hour later than usual. This lab-meeting will take place in "Darwin", as has previously been announced. Hopefully, Martin will join us and provide some input on the papers. We will discuss one paper on niche conservatism in North American Jays, and one manuscript of ours that has already been sent out by Maren Wellenreuther. Send Maren an e-mail if you have not yet received this manuscript (maren.wellenreuther@zooekol.lu.se).

Hi from Perth

Hi all,

A quick update from here down under at the ISBE conference. Today is the last day, and so there is only one more session is to come and the Hamilton lecture, which will be held by Nick Davies this time, one of my personal heroes in the field of behavioral biology. Looking forward! Also, I’m pleased to inform you that Thomas Gosden and I gave a talk in the same session yesterday afternoon. Tom gave an excellent presentation of his ongoing work, to a very enthusiastic audience. I think my talk was well received as well, though that is of course up to the audience to judge, but at least there were plenty questions. (Tom said I did a good job ;) ).

I’ve been looking for an emerging theme at this edition of the ESEB, as in previous years conferences were often overwhelmingly about one subject ( a few years ago it was multiple sexual traits), but I am not sure there is one this year. If anything, it might be the question of why females mate multiply, from the particular angle of genetic compatibility. Also Nina Wedell’s plenary lecture was of course along that theme. I am looking forward to hearing her speak again when she is coming to Lund! Marianne Wolfner also had a very interesting presentation about interactions at the molecular level between male and female proteins in fertilization. Also personalities has been pretty prominent, like the previous ISBE.

It’s been a lot of fun, lots of varieties of talks available, though Tom missed quite a few of them since he had to write his talk (yes, the data were that fresh of the press).

We’re both looking forward to some travel afterwards. Tom is driving up western Australia, and I’m going to explore the jungle in Borneo! Our life sucks badly, you guys enjoy your Swedish October…

Cheers, Machteld and Tom.

Climatic niche similarity and geographic range limits in ecologically similar co-existing damselflies

Dear all,
Now it is time to discuss one of my papers again. Together with Keith Larson and Erik Svensson, I am currently working on a paper that investigates niche divergence in Calopteryx damselflies.

Speciation in the genus Calopteryx is largely thought to be de-coupled from ecology, and reproductive isolation seems to have evolved independent of habitat ecology, through sexual selection, social interactions, learning and/or genetic incompatibilities. For this reason, ecological differences between closely related odonates are a priori expected to be relatively minor, and the modest differences that exist are likely to have evolved post-speciation, reflecting ecological divergence after reproductive isolation was already achieved. We tested these predictions using a large habitat data set for the two largely co-existing species Calopteryx splendens and C. virgo in Sweden and Finland and then employed spatial modelling techniques to identify the:

(i) environmental habitat characteristics, amount of niche overlap and degree of habitat specialisation,

(ii) combined and interactive effects of environment and predators and

(iii) ecological differences between allopatric and sympatric populations.

It will be great to discuss our findings with you next week (as usual we meet on Wednesday the 6th of October at 10:15 at the Darwin room, Lund University). Erik has also suggested to read a recent paper by John E. McCormack, Amanda J. Zellmer, and L. Lacey Knowles. Their work focused on niche divergence and its role in speciation in Mexican Jays.

DOES NICHE DIVERGENCE ACCOMPANY ALLOPATRIC DIVERGENCE IN APHELOCOMA JAYS AS PREDICTED UNDER ECOLOGICAL SPECIATION?: INSIGHTS FROM TESTS WITH NICHE MODELS

I will circulate the Evolution paper by McCormack et al. (2010) and the manuscript via email. If I have not included you in the email list and you would like to read and comment on these papers, then please send an email Maren.Wellenreuther@zooekol.lu.se

I will bring fika to the next meeting.

Have fun, Maren