Visit to EXEB by Masahito Tsuboi and talk about phenomics and the integration of micro- and macroevolution

Posted by Erik Svensson

For next week's EXEB-meeting (Tuesday August 23 at 10.00 in "Argumentet"), I am happy to welcome an outside visitor: Dr. Masahito Tsuboi from the Centre for Ecological and Evolutionary Synthesis (CEES) and the "Macroevolution Group". Masahito is currently a postdoc in Thomas F. Hansen's lab at Oslo University.

Masahito is visiting my lab next week to discuss some future research collaboration, and will give a talk about his research entitled:


Bridging the gap between micro- and macro-evolution: a challenge of quantitative phenomics

Below is the Abstract of the talk and some information about Masahito's research background:

Abstract: One of the most enduring challenges in evolutionary biology is to understand how evolutionary processes observed at population levels scale up to the diversity observed at species or higher taxonomic levels. Over the past decades, theoretical maturation of quantitative genetics, development of phylogenetic comparative methods and accumulation of high quality phenotypic data have collectively start offering solutions to fundamental issues in linking micro- and macro-evolution. Applying quantitative genetic theories for macroevolutionary phenotypic data, my research tries to assess if and how tempo and mode of macroevolution could be understood by microevolutionary patterns. In my seminar, I will first briefly outline my idea and present some preliminary results. A stronger focus then would be placed on discussing the approach and further scopes.

About me: I obtained PhD degree last year from Uppsala University, Sweden, working with Prof. Niclas Kolm on brain size evolution in cichlids, pipefishes and seahorses primarily from above-species, macroevolutionary, perspectives. Currently, I am a Postdoctoral fellow funded by Japanese Society for Promotion of Science (JSPS) based in University of Oslo, Norway, working with Prof. Thomas Hansen on the link between micro- and macro-evolution using dataset of vertebrate brain size, deer antler size, and fly wing morphology. 

"Fika" will be available. Everybody should be most welcome!

First EXEB-meeting fall 2016: on the evolution of coral snake mimicry

Posted by Erik Svensson

I hope everybody have enjoyed the summer and has had some time to relax. It is time to start this fall's EXEB-meetings, and suggest we meet and discuss this recent beutiful paper on the evolution of Batesian mimicry between coral snakes and king snakes by Allison Rabosky and colleagues. The paper is open access and can be downloaded here. This paper contains a nice mixture of phylogenetic comparative methods, macroevolutionary questions, colour evolution, mimicry and herps! What more could one ask for? Abstract is appended below.

When: Tuesday August 16 at 10.00

Where: "Argumentet", 2nd floor, Ecology Building. 

I will bring "fika" :)

Coral snakes predict the evolution of mimicry across New World snakes 

Alison R. Davis Rabosky, Christian L. Cox, Daniel L. Rabosky, Pascal O. Title, Iris A. Holmes, Anat Feldman, Jimmy A. McGuire

Nature Communications 7, Article number: 11484 doi:10.1038/ncomms11484

Abstract

Batesian mimicry, in which harmless species (mimics) deter predators by deceitfully imitating the warning signals of noxious species (models), generates striking cases of phenotypic convergence that are classic examples of evolution by natural selection. However, mimicry of venomous coral snakes has remained controversial because of unresolved conflict between the predictions of mimicry theory and empirical patterns in the distribution and abundance of snakes. Here we integrate distributional, phenotypic and phylogenetic data across all New World snake species to demonstrate that shifts to mimetic coloration in nonvenomous snakes are highly correlated with coral snakes in both space and time, providing overwhelming support for Batesian mimicry. We also find that bidirectional transitions between mimetic and cryptic coloration are unexpectedly frequent over both long- and short-time scales, challenging traditional views of mimicry as a stable evolutionary ‘end point’ and suggesting that insect and snake mimicry may have different evolutionary dynamics.

 

On linking ecology to sexual selection

Together with John Waller, I have a paper that is now out in American Naturalist as an E-article, meaning that it is "Open Acess" and possible for anyone to download. Go here, if you would like to download a PDF of this paper. I am very much in favour of the OA-model of publishing, and I certainly hope that the publication fees we paid will also result in more citations.

This study, which was fun to do and write up, takes a look at the important link between ecology and sexual selection. We were interested in the functional significance and evolutionary consequences of wing pigmentation in calopterygid damselflies, and we used a mixture of comparative phylogenetic analyses and field studies using thermal imaging to adress this issue. In particular, we wanted to see if there was any obvious thermal benefit of male wing pigmentation, which also has important functions in sexual selection, male-male competition and species recognition. Turns out that the evidence for such a thermal benefit is mixed, although there is a clear biogeographic signature in the sense that pigmented clades are more common in northern regions and temperate climates.

Wing pigmentation is also significantly associated with eleved speciation and extinction rates, using so-called BiSSE-analyses ("Binary Speciation and Extinction") as implemented in Diversitree. This latter result provides comparative support to our previous experimental work demonstrating that wing pigmentation functions as a species recognition character between C. splendens and C. virgo, and suggest that wing pigmentation is generally involved across the entire group as a promoter of speciation, although most species formed by such non-ecological sexual selection tend to go extinct fairly soon after they have formed.

In general, I think there are too few studies where comparative approaches and field experiments are combined, as both have strength and weaknesses and inferences could be stronger if they are combined (Disclaimer: in case some sensitive theoretical ecologist reads this post, I do of course also think there are other interesting and useful research approaches, such as mathematical models).

Ecology and Sexual Selection: Evolution of Wing Pigmentation in Calopterygid Damselflies in Relation to Latitude, Sexual Dimorphism, and Speciation

American Naturalist (in press, November 2013)

Erik I. Svensson* and John T. Waller

Evolutionary Ecology Unit, Department of Biology, Lund University, SE-223 62 Lund, Sweden

Abstract

Our knowledge about how the environment influences sexual selection regimes and how ecology and sexual selection interact is still limited. We performed an integrative study of wing pigmentation in calopterygid damselflies, combining phylogenetic comparative analyses, field observations and experiments. We investigated the evolutionary consequences of wing pigmentation for sexual dimorphism, speciation, and extinction and addressed the possible thermoregulatory benefits of pigmentation. First, we reconstructed ancestral states of male and female phenotypes and traced the evolutionary change of wing pigmentation. Clear wings are the ancestral state and that pigmentation dimorphism is derived, suggesting that sexual selection results in sexual dimorphism. We further demonstrate that pigmentation elevates speciation and extinction rates. We also document a significant biogeographic association with pigmented species primarily occupying northern temperate regions with cooler climates. Field observations and experiments on two temperate sympatric species suggest a link between pigmentation, thermoregulation, and sexual selection, although body temperature is also affected by other phenotypic traits such as body mass, microhabitat selection, and thermoregulatory behaviors. Taken together, our results suggest an important role for wing pigmentation in sexual selection in males and in speciation. Wing pigmentation might not increase ecological adaptation and species longevity, and its primary function is in sexual signaling and species recognition.

Updated information about lab-meeting on April 9: ERC, phylogenies and tropical diversification

This is an update about the coming lab-meeting on Tuesday April (10.30), as there was some mis-communication, and it turns out Lesley will not be able to attend the meeting due to a course in landscape genetics, and this is probably also the case for Rachel and Maren. The lab-meeting on Tuesday will start with  Jessica presenting her ERC-talk for the coming interview in Brussels, and she can then get final feedback from the lab-members that attend. Our new student Anais from Cataluna has also promised to bring some catalunian "fika", and we can try out the red wine she brought last week.

Then, we should discuss this paper that I originally suggested which deals with how the use of multiple phylogenies can be used to answer basic ecological and evolutionary questions about the niche conservatism and range expansions and test the classical "tropical conservatism" hypothesis. This paper is in press in Evolution, and is quite long, but in case you have time you can also read the shorter paper Lesley suggested that was published in Ecology Letters. 

Both these papers are thematically similar and demonstrate the power of a phylogenetic perspective and modern comparative methods to address fundamental problems and general processes in ecology and evolution. The titles and abstracts of both papers are posted below. Enjoy!

WHAT CAN MULTIPLE PHYLOGENIES SAY ABOUT THE LATITUDINAL DIVERSITY GRADIENT? A NEW LOOK AT THE TROPICAL CONSERVATISM, OUT OF THE TROPICS, AND DIVERSIFICATION RATE HYPOTHESES

1. Roland Jansson, 
2. Genoveva Rodríguez-Castañeda, 
3. Larisa E. Harding

We reviewed published phylogenies and selected 111 phylogenetic studies representing mammals, birds, insects, and flowering plants. We then mapped the latitudinal range of all taxa to test the relative importance of the tropical conservatism, out of the tropics, and diversification rate hypotheses in generating latitudinal diversity gradients. Most clades originated in the tropics, with diversity peaking in the zone of origin. Transitions of lineages between latitudinal zones occurred at 16–22% of the tree nodes. The most common type of transition was range expansions of tropical lineages to encompass also temperate latitudes. Thus, adaptation to new climatic conditions may not represent a major obstacle for many clades. These results contradict predictions of the tropical conservatism hypothesis (i.e., few clades colonizing extratropical latitudes), but support the out-of-the-tropics model (i.e., tropical originations and subsequent latitudinal range expansions). Our results suggest no difference in diversification between tropical and temperate sister lineages; thus, diversity of tropical clades was not explained by higher diversification rates in this zone. Moreover, lineages with latitudinal stasis diversified more compared to sister lineages entering a new latitudinal zone. This preserved preexisting diversity differences between latitudinal zones and can be considered a new mechanism for why diversity tends to peak in the zone of origin.

Species interactions constrain geographic range expansion over evolutionary time

Alex L. Pigot^*, 

Joseph A. Tobias

Whether biotic interactions limit geographic ranges has long been controversial, and traditional analyses of static distribution patterns have made little progress towards resolving this debate. Here, we use a novel phylogenetic approach to test whether biotic interactions constrain the transition to secondary sympatry following speciation. Applying this temporal framework to a diverse clade of passerine birds (Furnariidae), we reject models of geographic range overlap limited purely by dispersal or environmental constraints, and instead show that rates of secondary sympatry are positively associated with both the phylogenetic and morphological distance between species. Thus, transition rates to sympatry increase with time since divergence and accelerate as the ecological differences between species accumulate. Taken together, these results provide strong empirical evidence that biotic interactions – and primarily ecological competition – limit species distributions across large spatial and temporal scales. They also offer phylogenetic and trait-based metrics by which these interactions can be incorporated into ecological forecasting models.