Greetings from Oxford

I am currently visiting the well-known university town Oxford (UK), where I have given an invited research seminar at the Edward Grey Institute, which belongs to the famous Department of Zoology at South Parks Road. It has been very stimulating, as usual when interacting with research colleagues, and there has also been plenty of times for walking in the city and enjoying several pints of nice bitter!

I can strongly recommend a visit to Oxford with its cosy and history-laden academic atmosphere. Enjoy the pictures!

Visit by Thomas F. Hansen and Arnaud Le Rouzic this week

This week our department will be visited by theoretical evolutionary biologist Thomas F. Hansen, who is currently professor at University of Oslo in Norway. I am pleased to host Thomas during his visit to Lund, as I visited his department Centre for Ecological and Evolutionary Synthesis (CEES) in May last year, and it is now my time to take care of him as he visits our department.

Thomas former postdoc Arnaud Le Rouzic will also visit us, and will give a short presentation of his research during our lab-meeting on Wednesday (10.15; Thomas will arrive later, in Wednesday afternoon). During our lab-meeting on Wednesday, I was thinking we should also discuss a paper about evolutionary quantative genetics, authored by Steve Chenoweth et al:

Author(s): Chenoweth SF (Chenoweth, Stephen F.)1, Rundle HD (Rundle, Howard D.)2,3, Blows MW (Blows, Mark W.)1

AMERICAN NATURALIST Volume: 175 Issue: 2 Pages: 186-196 Published: FEB 2010

Abstract: Although divergent natural selection is common in nature, the extent to which genetic constraints bias evolutionary trajectories in its presence remains largely unknown. Here we develop a general framework to integrate estimates of divergent selection and genetic constraints to estimate their contributions to phenotypic divergence among natural populations. We apply these methods to estimates of phenotypic selection and genetic covariance from sexually selected traits that have undergone adaptive divergence among nine natural populations of the fly Drosophila serrata. Despite ongoing sexual selection within populations, differences in its direction among them, and genetic variance for all traits in all populations, divergent sexual selection only weakly resembled the observed pattern of divergence. Accounting for the influence of genetic covariance among the traits significantly improved the alignment between observed and predicted divergence. Our results suggest that the direction in which sexual selection generates divergence may depend on the pattern of genetic constraint in individual populations, ultimately restricting how sexually selected traits may diversify. More generally, we show how evolution is likely to proceed in the direction of major axes of genetic variance, rather than the direction of selection itself, when genetic variance-covariance matrices are ill conditioned and genetic variance is low in the direction of selection.

The paper can be downloaded here. Most of you probably already know that Steve Chenoweth is the postdoc host of Tom Gosden, former PhD-student in our lab.

Also, you should of course not miss the exciting Thursday seminar (18 February at 14.00 in "Blue Hall") by Thomas, also on the theme of quantitative genetics, with the title:

Measuring evolvability and constraints with examples from the evolution of Dalechampia blossoms

We do thus have a very exciting week ahead of us!

Our research is featured in TREE and we get a cover photo!

In the latest issue of Trends in Ecology & Evolution, the cover photo is a couple of mating damselflies (Ischnura elegans), one of our favourite study species. It is of course very pleasing to see both this photo on the cover, and the flattering coverage of our research in a a review article by Charlie K. Cornwallis and Tobias Uller, entitled Towards an evolutionary ecology of sexual traits. Cornwallis and Uller discusses a number of recent articles about the dynamics of sexual selection over several generations, including a paper published by Tom Gosden and me entitled Spatial and temporal dynamics in a sexual selection mosaic (in Evolution, 2008).

Here is the abstract of the review article by Cornwallis and Uller:

References and further reading may be available for this article. To view references and further reading you must purchase this article.

Charlie K. Cornwallis^a, and Tobias Uller^a

^a Edward Grey Institute, Department of Zoology, University of Oxford, South Parks Road, Oxford, UK, OX1 3PS

Empirical studies of sexual traits continue to generate conflicting results, leading to a growing awareness that the current understanding of this topic is limited. Here we argue that this is because studies of sexual traits fail to encompass three important features of evolution. First, sexual traits evolve via natural selection of which sexual selection is just one part. Second, selection on sexual traits fluctuates in strength, direction and form due to spatial and temporal environmental heterogeneity. Third, phenotypic plasticity is ubiquitous and generates selection and responses to selection within and across generations. A move from purely gene-focused theories of sexual selection towards research that explicitly integrates development, ecology and evolution is necessary to break the stasis in research on sexual traits.

Next lab meeting - wednesday 10 02 2010

For the next lab meeting, I thought that we could explore a bit a field that we are not all very familiar with: developmental evolution. The real reason is that I am planning a postdoc with Anna Qvarnström, from Uppsala University, which is gonna be about the role of ontogenetic trajectories on adaptive divergence and speciation, and I would be extremely grateful if I could get input on my VR-application from all of you who can come. The main idea is that heterochrony of for example secondary sexual characters may have an effect on assortative mating between populations and ultimately speciation. I will work on the flycacther hybrid zone and mainly using quantitative genetics techniques to answer this question among others. Thus, it would be really nice if you have the time to read my application and that we discuss what can be improved during the lab meeting. I will send you by email the application tomorrow. Erik and I thought that it would also be nice to read a short paper which discuss these kinds of questions, and I chose a paper by Sean Rice which is, I think, a nice introduction to the field: Proc. Natl. Acad. Sci. USA
Vol. 94, pp. 907–912, February 1997

Here is the abstract:

Heterochrony has become a central organizing concept relating development and evolution. Unfortunately, the standard definition of heterochrony—evolutionary change in the rate or timing of developmental processes—is so broad as to apply to any case of phenotypic evolution. Conversely, the standard classes of heterochrony only accurately describe a small subset of the possible ways that ontogeny can change. I demonstrate here that the nomenclature of heterochrony is meaningful only when there is a uniform change in the rate or timing of some ontogenetic process, with no change in the internal structure of that process. Given two ontogenetic trajectories, we can test for this restricted definition of heterochrony by asking if a uniform stretching or translation of one trajectory along the time axis superimposes it on the other trajectory. If so, then the trajectories are related by a uniform change in the rate or timing of development. If not, then there has been change within the ontogenetic process under study. I apply this technique to published data on fossil Echinoids and to the comparison of human and chimpanzee growth curves. For the Echinoids, some characters do show heterochrony (hypermorphosis), while others, which had previously been seen as examples of heterochrony, fail the test—implying that their evolution involved changes in the process of development, not just the rate at which it proceeded. Analysis of human and chimpanzee growth curves indicates a combination of neoteny and sequential hypermorphosis, two processes previously seen as alternate explanations for the differences between these species.

I hope you can all come. I will try to remember to bring fika.

Information about Fulbright scholarships on Wednesday February 3

This coming Wednesday (February 3), there will first be a presentation from Heather Halenbeck, an officer from the Fulbright Commission, who will inform about their prestigious scholarships in "Darwin" at 10.00, i. e. during our regular lab-meeting time. This presentation will start at 10.00, and both undergraduates, PhD-students, postdocs and senior scientists are welcome to attend.

Heather's presentation will end around 11.00, whereafter our regular lab-meeting will start, with two papers for discussion chosen by Mactheld Verzijden about insect learning. You are most welcome to attend both of these meetings, of course. Thus, either come at 10.00 or at 11.00, depending on your preferences. Please spread this information also to other interested in the Ecology Building.

Papers for discussion weds 3 Feb

Erik suggested that I pick next weeks’ lab meeting papers to discuss, and so I have.
My main topic of study is mate choice learning and evolution, and I have done experimental work on birds and fish regarding this topic. Though I don’t think there is fundamentally anything different about this topic regarding vertebrates and invertebrates, I have chosen two papers that deal with insect learning behavior. This is to hopefully convince you (if you weren’t already) that this is an interesting topic, and potentially fruitful to study in damselflies. The first paper is a review, by Reuven Dukas , about the different types of learning known in insects and the evolutionary implications. The second paper is an experiment that shows some very interesting interactions between circadian clocks and male mate preference learning.

here are links to the two papers:

Evolutionary biology of insect learning. R. Dukas 2008

Social Experience Modifies Pheromone Expression and Mating Behavior in Male Drosophila melanogaster, Krupp et al 2008

Enjoy,

Machteld

TREE-article about antagonistic coevolution, resistance and tolerance

Together with my colleague Lars Råberg, I have recently published an "Opinion"-article in Trends in Ecology & Evolution, that has just come out on "early view". This article deals with the different roles of resistance and tolerance in antagonistic coevolutionary interactions involving animals.

Basically, we argue that the evolution of victim tolerance, instead of resistance, might halt coevolutionary arms races and make them less probable, in contrast to if the victim evolves resistance instead. This idéa has been floating around for quite a while in the plant litterature, but we extend the idéa to animals and to other types of enemy-victim interactions. We illustrate this using a variety of empirical examples from several different types of antagonistic enemy-victim interactions involving animals. Here is the abstract and link if you are interested:

Resistance and tolerance in animal enemy–victim coevolution

References and further reading may be available for this article. To view references and further reading you must purchase this article.

Erik I. Svensson and Lars Råberg

Victim defence against enemies can be divided into resistance (minimizing successful enemy attacks) and tolerance (minimizing the fitness impact of enemy attacks). Although resistance has a negative effect on enemy fitness, tolerance, by this definition, does not necessarily; the relative importance of resistance and tolerance within a population might therefore affect enemy–victim coevolution. Resistance and tolerance have been distinguished in studies of plant defence, whereas most studies of antagonistic interactions in animals have focused on resistance, neglecting tolerance. We suggest that tolerance is also an important means of defence in animal victim–enemy interactions such as brood parasitism, mating interactions and territoriality. We discuss the potential coevolutionary consequences of tolerance variation in these animal enemy–victim interactions.