Our new paper about learning in sexual selection and speciation is now out in TREE

Our paper in Trends in Ecology & Evolution about the role of learning in sexual selection and speciation is now online, and you can find a link to it here. Soon the reprints will hopefully come, and then you can ask Machteld Verzijden for a copy (machteld.verzijden@biol.lu.se). Hopefully, this paper will stimulate increased interest and more experimental and observational studies in this fast moving field.

Below, you will find more details about the paper. Enjoy!

The impact of learning on sexual selection and speciation

• Machteld N. Verzijden 
• Carel ten Cate, 
• Maria R. Servedio, 
• Genevieve M. Kozak, 
• Jenny W. Boughman, 
• Erik I. Svensson

http://dx.doi.org/10.1016/j.tree.2012.05.007

Learning is widespread in nature, occurring in most animal taxa and in several different ecological contexts and, thus, might play a key role in evolutionary processes. Here, we review the accumulating empirical evidence for the involvement of learning in mate choice and the consequences for sexual selection and reproductive isolation. We distinguish two broad categories: learned mate preferences and learned traits under mate selection (such as bird song). We point out that the context of learning, namely how and when learning takes place, often makes a crucial difference to the predicted evolutionary outcome. Factors causing biases in learning and when one should expect the evolution of learning itself are also explored.

On blogging, tweeting and non-ecological speciation

One of the reasons to have a scientific blog, whether an individual-based or a group-based one like ours, is that you might increase the attention to your research, and hopefully also increase the interest in your work, boost your citation rates and perhaps become more succesful as a scientist in grant applications. But is there any real evidence for this, or is it pure wishful thinking? As a matter of fact, some quantitative evidence is starting to accumulate now, that blogging and tweeting does increase the interest in your work, as judged by increasing number of downloads. Thus, unlike many other scientists who might consider blogging waste of time, I think it is a mistake to dismiss social media in the scientific process these days.

In the spirit of this, and with the hope to increase the interest in my research, I post my latest article that is published in Organisms, Diversity & Evolution and which is entitled: "Non-ecological speciation, niche conservatism and thermal adaptation: how are they connected?" It is a critical review of the current state of ecological speciation theory, its assumptions and limitations, and with a discussion about some alternatives to ecological speciation. Download it, read it or cite it (or do it all!)! I also present some thermal image data on the thermal niches of two sympatric calopterygid damselflies: Calopteryx splendens and C. virgo.

This paper was fun to write, and it largely grew out of discussions I had with Andrew Hendry and some other folks at Uppsala last year, when I visited the Evolutionary Biology Centre (EBC) in conjunction with the PhD-student defence's of Niclas Vallin and Paolo Innocenti. The Abstract and paper details are given below. Now, perhaps Maren Wellenreuther and Anna Runemark will post about some other recent lab-publications that have come out recently?

Abstract

During the last decade, the ecological theory of adaptive radiation, and its corollary “ecological speciation”, has been a major research theme in evolutionary biology. Briefly, this theory states that speciation is mainly or largely the result of divergent selection, arising from niche differences between populations or incipient species. Reproductive isolation evolves either as a result of direct selection on mate preferences (e.g. reinforcement), or as a correlated response to divergent selection (“by-product speciation”). Although there are now many tentative examples of ecological speciation, I argue that ecology’s role in speciation might have been overemphasised and that non-ecological and non-adaptive alternatives should be considered more seriously. Specifically, populations and species of many organisms often show strong evidence of niche conservatism, yet are often highly reproductively isolated from each other. This challenges niche-based ecological speciation and reveals partial decoupling between ecology and reproductive isolation. Furthermore, reproductive isolation might often evolve in allopatry before ecological differentiation between taxa or possibly through learning and antagonistic sexual interactions, either in allopatry or sympatry. Here I discuss recent theoretical and empirical work in this area, with some emphasis on odonates (dragonflies and damselflies) and suggest some future avenues of research. A main message from this paper is that the ecology of species differences is not the same as ecological speciation, just like the genetics of species differences does not equate to the genetics of speciation.

Keywords  Mike May Festschrift – Calopteryx – Learning – Learned mate preferences – Niche – Sexual conflict – By-product speciation – IR-camera – Thermal imaging – Ectotherms – Sexual isolation

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.

FroSpects-meeting on non-adaptive and non-ecological speciation in Lund August 18 2012

During the past decade, the ecological theory of adaptive radiation and adaptive speciation has been a main focus of interest in much speciation research. Much of current thinking in this area assumes that incipient species are formed as a direct or indirect result of niche-based ecological differences and divergent natural selection.

However, more recently it has been an increased interest also in non-ecological and non-adaptive speciation in groups like birds, fish, amphibians and insects. Some radiations are simply not very likely to result from divergent ecological selection, as species are often ecologically similar and show high degree of niche conservatism, yet speciation obviously happens also in these groups. Behavior might play a crucial role in driving speciation processes in these circumstances, including learned mate preferences, sexual selection and sexual conflict. These and related topics will be the focus of one-day scientific meeting at Lund University (Sweden) on August 18 2012.

On August 18 2012, we are therefore proud to organize this one-day meeting (free of charge) entitled "The Role of Behaviour in Non-adaptive and Non-ecological Speciation".

This meeting is funded by the European Science Foundation's (ESF) Frontier's of Speciation Research FroSpects, and will be one of several post-conference symposia the day after The International Behavioural Ecology Congress ("ISBE 2012") that will take place between August 12 and August 17 2012. 

Note that although the ESF-meeting is free of charge, the preceeding ISBE-congress is not. The meeting is open both for ISBE-participants and those who wish to only come for to the speciation meeting. Coffee and refreshments will be served on August 18, but participants will have to fund and organize travel, meals and ackomodation for themselves.

In addition to three excellent invited keynote speakers (Dr. Rampal S. Etienne, Prof. Kerry Shaw and Prof. John Wiens), we will also accept contributed talks (15 minutes, including 3 minutes of questions) to this meeting. Send an abstract (100-200 words) to Dr. Maren Wellenreuther (maren.wellenreuther@biol.lu.se), no later than April 2012.  More general questions about the meeting can be answered by Prof. Erik Svensson (erik.svensson@biol.lu.se).

Organizing committé:


Prof. Erik Svensson
Dr. Machteld Verzijden
Dr. Maren Wellenreuther
Ms. Anna Runemark 

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!

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.

Lab-meeting on phenotypic plasticity, learning, sexual selection and mate preferences

This coming Wednesday (26 May), I wish to discuss a recent TREE-article by Charlie Cornwallis and Tobias Uller that recently came out. The title of this article is Towards an evolutionary ecology of sexual traits. I was one of the reviewers on this article, and I think they have some interesting things to say. Whether you agree or not with their general message, I think this paper should stimulate some discussion.

Also, postdoc Machteld Verzijden might send out one of her manuscripts about mate preference evolution in fish, that she want some input on. If she is able to finish this manuscript, she will send it out by e-mail to the group tomorrow (Tuesday).

Any fika-volunteer?