A second try to go the Himalayas

 Posted by Erik Svensson

Since we did not have time to discuss the paper on avian species diversity in eastern Himalaya last week, due to the fact that we enjoyed so much listening to Jessica's talk and drinking cava, we make a new try this coming week. Here is the paper by Trevor Price and his colleagues in Nature.

 For a short summary of the findings in the paper I also recomment this a brief comment about the study by Arne Mooers, in a "News & Views"-article in the same issue of Nature, which is also worth reading.

The picture above shows the national bird of Nepal, the charismatic Himalayan Monal, a pheasant that I was lucky to see myself during my bird watching tour to Nepal in 1991, along the slopes of the Anapurna Trekk. The paper interests me for personal reasons, as already as a young bird watcher in 1991, I wondered about the amazing species diversity and how it came about, before I was very knowledgeable in ecology and evolutionary theory.

Date and time: Tuesday September 30, 10.30
Where: "Argumentet", second floor (Ecology Building)

I will bring fika!

Lab-meeting on ERC-interview, PNAS-accept, niche-filling, supply and demand and avian species richness in the Himalayas

Next week, we will listen to Jessica Abbott, giving her "practice talk" before her interview in Brussels (Belgium) for an ERC Junior Grant, which we certainly hope she will get this time (it is the second year in a row that Jessica has been shortlisted for this prestiguous grant). We should all try to give good feedback to Jessica so that her chances to get this grant are maximized!

We will also celebrate that Jessica, I, our two former postdocs Natsu and Yuma and Jostein Kjaerandsen got an accept on our paper on sexual selection on Wing Interference Patterns (WIP:s) in Drosophila melanogaster in Proc. Natl. Acad. Sci. USA. Jessica has promised to bring some nice "fika", and I will bring some "bubble" to celebrate this.

Finally, Jessica asked me to pick a short paper to discuss as well, and I have chosen a relatively recent paper on adaptive radiation, speciation and niche filling in the Himalayan bird fauna. I do this partly for personal reasons, as this is a fascinating and extremely species-rich region of the world where I travelled as a young student and avid bird watcher in 1991, just before the start of my PhD in 1992. I hope you will enjoy this beatiful paper (Abstract is provided below). You might also want to read the "News and Views" comment on this paper by Arne Mooers, which summarizes the main findings.

Date and time: Tuesday, September 23, 10.30
Where: "Argumentet", 2nd floor, Ecology Building. 
  
Trevor D. Price et al.

Niche filling slows the diversification of Himalayan songbirds

Nature 509, 222–225 (08 May 2014) doi:10.1038/nature13272

Speciation generally involves a three-step process—range expansion, range fragmentation and the development of reproductive isolation between spatially separated populations1, 2. Speciation relies on cycling through these three steps and each may limit the rate at which new species form1, 3. We estimate phylogenetic relationships among all Himalayan songbirds to ask whether the development of reproductive isolation and ecological competition, both factors that limit range expansions4, set an ultimate limit on speciation. Based on a phylogeny for all 358 species distributed along the eastern elevational gradient, here we show that body size and shape differences evolved early in the radiation, with the elevational band occupied by a species evolving later. These results are consistent with competition for niche space limiting species accumulation5. Even the elevation dimension seems to be approaching ecological saturation, because the closest relatives both inside the assemblage and elsewhere in the Himalayas are on average separated by more than five million years, which is longer than it generally takes for reproductive isolation to be completed2, 3, 6; also, elevational distributions are well explained by resource availability, notably the abundance of arthropods, and not by differences in diversification rates in different elevational zones. Our results imply that speciation rate is ultimately set by niche filling (that is, ecological competition for resources), rather than by the rate of acquisition of reproductive isolation.

Lab-meeting on why and how to estimate components of reproductive isolation

This coming Wednesday (November 2, 2011, 13.00), our lab-meeting will be dedicated to the Why and How to estimate components of pre- and postmating isolation, starting with a key paper and method developed by Douglas Schemske's group, which you can download here. This paper was published in 2003 in Evolution, i. e. fairly recently, but the method has already become popular. Here is an empirical application to birds, a study on crossbills by Craig Benkman's group, which you can download here, and here is another empirical application to damselflies by Adolfo Cordero's group, which you can download here.

I suggest that we read the plant paper by Schemske's group in detail, as it is a key publication where the method was presented. This paper has been cited 166 times, quite a sign of it being an important paper.  Then we also read, although more extensively,  the two other papers to see how the method has been applied to other systems.

Lab meeting: 21 April 2010 at 10:15am, Darwin room

Good morning everybody,

We will have a lab meeting this week. Two things are on the agenda:
1) Fabrice has been invited to give a seminar in Linköping and would like to get your feedback on his presentation. He will speak about

Joint effects of migration modification and assortative mating in the early stages of ecological speciation

Fabrice Eroukhmanoff, Anders Hargeby & Erik I. Svensson

ABSTRACT: The question of how diverging populations might become separate species by restraining gene flow is a central issue in evolutionary biology. Assortative mating might emerge early during divergence, but migration modification can also play an important role in speciation. We demonstrate that two recently diverged ecotypes of a freshwater isopod have rapidly developed pre-mating isolation. This is consistent with ecological speciation theory, which predicts that sexual isolation arises as a byproduct of ecological divergence. However, migration modification acts as the main barrier to gene flow, although the joint emergence of these two isolating mechanisms has facilitated adaptive divergence. These results underscore that migration modification might be as important as assortative mating in the early stages of ecological speciation.

2) Tina would like to get your input on some 'work in progress'. Please email me under Maren.wellenreuther@zooekol.lu.se to get the attachments - if you have not received them already.

Any fika volunteers for this week? See you all on Wednesday, Maren

Lab-meeting on good genes and ecological speciation January 13 2009

It is time for lab-meetings again, and what would be more suitable to start with than a theoretical paper about "good genes" and speciation? You will find this paper here, and it has recently been published in Science by van Doorn et al. You will find the abstract below:

On the Origin of Species by Natural and Sexual Selection

G. Sander van Doorn,^1,2,*, Pim Edelaar,^3,4,5,* Franz J. Weissing³

Ecological speciation is considered an adaptive response to selection for local adaptation. However, besides suitable ecological conditions, the process requires assortative mating to protect the nascent species from homogenization by gene flow. By means of a simple model, we demonstrate that disruptive ecological selection favors the evolution of sexual preferences for ornaments that signal local adaptation. Such preferences induce assortative mating with respect to ecological characters and enhance the strength of disruptive selection. Natural and sexual selection thus work in concert to achieve local adaptation and reproductive isolation, even in the presence of substantial gene flow. The resulting speciation process ensues without the divergence of mating preferences, avoiding problems that have plagued previous models of speciation by sexual selection.

Time and place as usual: "Darwin" at 10.15 (immediately after the "Pheromone group"). It would be great if you could respond below if you will come (or not!), as I am not sure how many are back in town. Any fika-volunteer?