Merry Christmas and Happy New Year 2012!

 Another year has soon passed, and I wish to say Merry Christmas and a Happy New Year to all of you involved in research in lab. This includes both those of you who are currently in Lund, and those of you who are elsewhere in the world, such as in exotic countries like Norway and Australia.

The pictures above come from the Christmas Meeting in the new Evolutionary Ecology Unit, which was held last week. After talks in the afternoon by several group members and other colleagues in the new unit, it was time for the traditional Swedish Christmas Table, or "Julbord" As you see, Jessica Abbott participated too, after several years of exile in Canada and Uppsala. Jessica will start her new position in Lund in January 2012, after receiving her "Junior Project Grant" from Vetenskapsrådet in 2011. Tina Karlsson also participated, and she will leave to start her postdoc in Finland (Helsinkki) in May 2012.

The year 2011 was an extremely successful year for our lab, in terms of succesful grant applications. Apart from Jessica obtaining a VR-grant and Tina getting a postdoc-grant from VR, Fabrice Eroukhmanoff obtained an EU/Marie Curie postdoc in December, and Machteld Verzijden got extension on her postdoc from the Wennergren Foundation. Considering the severe competition for grants these days, I am both amazed and proud of these achievements of you guys. And you should be as well, of course.

The year 2011 was also  successful in terms of publishing, with nice papers in leading journals, such as Animal Behaviour, BMC Evolutionary Biology, Heredity, Evolution, Journal of Evolutionary Biology, to name a few. We are clearly doing work that is interesting and relevant, and I have the feeling we are moving in the right direction to be even more succesful in the coming years.

Once again: Merry Christmas and enjoy the break! See you in 2012!

Congratulations to Fabrice Eroukhmanoff for obtaining postdoctoral EU-fellowship ("Marie Curie")

Former PhD-student Fabrice Eroukhmanoff, who is currently postdoc at CEES in Oslo (Norway) has apparently obtained a postdoctoral scholarship from the European Union through the "Marie Curie"-programme. As he recently obtained a two-year postdoctoral scholarship from the Swedish Research Council (VR), this means that he can stay longer in Oslo and be able to do more research, before possibly returning to Sweden.

On behalf of myself, as proud former advisor, and the rest of us, I wish to congratulate Fabrice for yet another impressive achievement. Well done!

Lab-meeting and some interesting evolutionary articles in Science

This week's lab-meeting will take place at an unusual time: Friday 9 December at 10.00 in "Argumentet". I hope you can make it, as Machteld and I will tell us a little bit about our impressions from the ASAB-meeting in London, where we recently participated. In addition, I would like to discuss two recent articles in Science which are of interest to evolutionary ecologists (and which are short reads). You will find more information about these papers below, including links and Abstracts.

First, there is this interesting study about negative frequency-dependent selection in voles: 

Negative Frequency-Dependent Selection of Sexually Antagonistic Alleles in Myodes glareolus

1. Mikael Mokkonen¹,*,
2. Hanna Kokko²,
3. Esa Koskela³,
4. Jussi Lehtonen²,⁴,
5. Tapio Mappes¹,
6. Henna Martiskainen³,
7. Suzanne C. Mills⁵

Abstract

Sexually antagonistic genetic variation, where optimal values of traits are sex-dependent, is known to slow the loss of genetic variance associated with directional selection on fitness-related traits. However, sexual antagonism alone is not sufficient to maintain variation indefinitely. Selection of rare forms within the sexes can help to conserve genotypic diversity. We combined theoretical models and a field experiment with Myodes glareolus to show that negative frequency-dependent selection on male dominance maintains variation in sexually antagonistic alleles. In our experiment, high-dominance male bank voles were found to have low-fecundity sisters, and vice versa. These results show that investigations of sexually antagonistic traits should take into account the effects of social interactions on the interplay between ecology and evolution, and that investigations of genetic variation should not be conducted solely under laboratory conditions. 

Second, there is this study on individual face recognition in paper wasps: 

Specialized Face Learning Is Associated with Individual Recognition in Paper Wasps

1. Michael J. Sheehan*,
2. Elizabeth A. Tibbetts

Abstract

We demonstrate that the evolution of facial recognition in wasps is associated with specialized face-learning abilities. Polistes fuscatus can differentiate among normal wasp face images more rapidly and accurately than nonface images or manipulated faces. A close relative lacking facial recognition, Polistes metricus, however, lacks specialized face learning. Similar specializations for face learning are found in primates and other mammals, although P. fuscatus represents an independent evolution of specialization. Convergence toward face specialization in distant taxa as well as divergence among closely related taxa with different recognition behavior suggests that specialized cognition is surprisingly labile and may be adaptively shaped by species-specific selective pressures such as face recognition.

Increasing visitor traffic to our blog

The visitor statistics to this blog has been going steadily upwards since it was first launched in spring 2009 (see graph above), and last month we actually had more than 5000 hits. Although bloggers built-in visitor statistics does not separate automated searches from web-engines from individuals that are really interested in our stuff, and although it does not track "unique" visitors, I think these numbers reflect an ongoing and positive trend, and increasing awareness of our research and the blog. It is probably a safe educated guess that several hundred visitors per month read our blog and find it interesting and worthwhile to read.

Hopefully, this increase will continue in the near future, as it often takes several years to build up a new blog and "brand it". Hopefully, the blog will also help us to attract students, postdocs and other outside collaborators and also spread more efficiently information about our ongoing studies and publications.  Sofar, we have mainly used it to announce lab-meetings, but we are increasingly using it also as a vehicle to inform about recent meetings that we have participated in, as Maren did recently when she was at "Blodbadet" in Stockholm, as also Fabrice did after he went to a hybridization workshop in Scotland, and as I also I did myself when I recently visited the ASAB Winter Meeting with Machteld.

Blogs and social media do certainly not replace traditional means of scientific communication, such as peer-reviewed publications in international journals. But they are certainly an important complement, and I am more and more convinced that they can have a positive impact and "spill-over effects" on such vital things as citation rates of papers.

I would therefore encourage you all, once again, to post interesting things, short or long, on this blog, along these lines, including interesting talks you have been to, or interesting articles you have stumbled upon. Together, we might make this blog an excellent outlet for the dissemination of research, both our own and others.

Some thoughts from ASAB:s winter meeting in London: remembering Mayr's and Tinbergen's legacies

Together with Machteld Verzijden from our lab, I recently attended the annual "winter meeting" for the Association for the Study of Animal Behaviour (ASAB), close to London Zoo. The theme for this year's meeting was "Why do animals mate with the "wrong" partner?", and you can find a list of the talks here. There were several interesting talks, including contributions from Marlene Zuk about "same-sex behaviour" and Karen Pfennig about adaptive hybridization in spadefoot toads. The most interesting talk, in my opinion, was however Tamra Mendelson, who pointed out the need for a clear operational definition of species recognition, and emphasized that it should be integrated with the need for a general theory of mate recognition.

Other contributions were more controversial, including a talk by Joan Roughgarden, about the evolution of cooperation and mutual affection, and Malin Ah-King from Uppsala University about the need for developing gender-neutral models of sexual selection. Malin Ah-King took as her starting point a model based on five demographic parameters that makes no assumptions about past evolutionary history of the two sexes and argued that the so-called "w-distribution" (distribution of male-female joint fitnesses) was crucial in determining the degree of mate acceptance and promiscuity. Although I see some validity in moving away from the evoutionary psychology tradition of stereotypic sex differences to better understand mating system evolution, the opposite approach, ignoring sex differences altogether seems to be a bit too drastic in my opinion. But I might have misunderstood some underlying assumptions of this model, of course.

Even more controversial was when Ah-King suggested that we should consider alternative explanations for why animals mate than the classical evolutionary one: that animals mate because natural selection favours reproduction and the transmission of genetic material across generations. King instead suggested that animals more often mate because of "pleasure", which to me seems to be making the classical mistake of confusing proximate ("mechanistic") and ultimate ("evolutionary") explanations of animal behaviour. 

As evolutionary biologist Ernst Mayr and ethologist Niko Tinbergen have taught us, proximate and ultimate explanations are not mutually exclusive, but rather complementary, and adress different "layers" in the explanation of behaviours and other traits. Thus, contrary to what Ah-King claimed, the two statements "animals mate because of pleasure" and "animals mate to maximize the transmission of their genes" are not contradicting each other. They can even be integrated by stating: "Animals have evolved pleasure of reproduction as an internal reward system because natural selection has favoured organisms which are efficient in spreading their genetic material".

This took very long time for many biologists to undertand, particularly for geneticists, physiologists and developmental biologists. There is a famous story about fly geneticist TH Morgan who, in the early twentieth century stated that: "Darwin thought that male birds had evolved bright plumage colouration because of sexual selection by female choice. We now know that this explanation was incorrect, and the reason why male birds have more bright plumage than females is because of difference in sex hormones".  It would be sad if the important conceptual insights about the crucial difference between proximate and ultimate explanations, so clearly explained by Mayr and Tinbergen were forgotten again. And yet, that is the impression I got after listening to Ah-King's talk.

Hybridization and Speciation

Recently, I participated in a very interesting Frospects workshop in the UK about hybridization and speciation and organized by Roger Butlin and Mike Ritchie, under the coordination of Ulf Dieckman. Several invited experts such as Godfrey Hewitt, Richard Abbott, James Mallet or Karin Pfennig presented their views on hybridization and how it is (or should be) more and more recognized as a creative evolutionary force in many aspects including speciation (one of the classic examples being homoploid or polyploidy hybrid speciation). But another (among many) particularly interesting discussion that took place originated from an argument presented by evolutionary and behavioral ecologist Karin Pfennig. It deals with the possible outcomes of reinforcement and how it might induce reproductive isolation between allopatric and sympatric populations of the same species through divergence of mate preferences. It is thus very relevant to some of the systems we are working on, such as Calopteryx damselflies.

Indeed, in some cases, selection against heterospecific matings may incidentally result in individuals from conspecific populations which are either situated in sympatry or allopatry leading to the initiation of reproductive isolation between formerly conspecific populations (Pfennig & Ryan 2006 Proc. Roy. Soc. B). For example, Jaenike et al. (2006, PloS Biology) showed that, between two sympatric species of Drosophila, strong hybrid inviability could not only select discrimination of heterospecifics, but also incidentally lead to discrimination of conspecifics from allopatric populations. Anpther example, although a bit more complicated as it involves different sympatric populations instead of allopatric and sympatric ones can be found in Hoskins et al. (2006, Nature), but there the data on divergence in mating preferences is quite interesting.

Remarkably, we have actually kind of obtained a similar result in one of our previous study (Svensson et al. 2006 Evolution), where we found that strong divergent sexual selection was accompanied by a significant decrease of female response towards conspecifics from other populations. This is corroborated by another study yet from our group, that found reduced gene flow between some of these populations (Svensson et al. 2004 Heredity), like it has been found in other systems (Rice and Pfennig 2010). I had myself never really thought about it that way, and this opened my mind a lot I must say on what Erik and others of our group have done in the past. And what about learning then? Well, we know it is likely to play an important role in divergence of mate preferences in our system (Svensson et al. 2010 Evolution), and all things considered it might even facilitate this process, as mate choice may change faster and thus the constraining effects of gene flow in the early stages will then not be an issue anymore.

We all concluded that evaluating this type of scenario may be possible with existing data or systems. In particular, studies of reinforcement and reproductive character displacement often involve comparisons of reproductive traits between sympatry and allopatry. But I guess in our case, there might be ways to use existing data and design new experiements to test specifically this type of hypothesis and whether such a process can actually promote speciation or why conspecific populations never really speciate, only maintaining a moderate level of divergence (genetic constraints, learning etc.?). Maybe you guys are already long aware of this, but I still wanted to shareit, as it was new for me, and I hope you find this as interesting as I did, and that it stimulates some new ideas maybe?

Some useful refs:


Jaenike J, Dyer KA, Cornish C, Minhas MS (2006) Asymmetrical reinforcement and Wolbachia infection in Drosophila. Plos Biology 4, 1852-1862.Hoskin CJ, Higgie M, McDonald KR, Moritz C (2005) Reinforcement drives rapid allopatric speciation. Nature 437, 1353-1356.

Pfennig KS, Ryan MJ (2006) Reproductive character displacement generates reproductive isolation among conspecific populations: an artificial neural network study. Proceedings Of The Royal Society Of London Series B-Biological Sciences 273, 1361-1368.

Rice AM, Pfennig DW (2010) Does character displacement initiate speciation? Evidence of reduced gene flow between populations experiencing divergent selection. Journal of Evolutionary Biology.

Svensson EI, Eroukhmanoff F, Friberg M (2006) Effects of natural and sexual selection on adaptive population divergence and premating isolation in a damselfly. Evolution 60, 1242-1253.

Svensson EI, Kristoffersen L, Oskarsson K, Bensch S (2004) Molecular population divergence and sexual selection on morphology in the banded demoiselle (Calopteryx splendens). Heredity 93, 423-433.