Does sexual and natural selection operate against each other or in the same direction?

Posted by Erik Svensson

During last week's lab-meeting we talked a little about the relationship between natural and sexual selection, and to what extent these processes are opposed to each other vs. operate in the same direction and favours the same phenotypic trait values. Next week we will continue discussing this theme based on a recent article about sexual and natural selection in fruitflies (Drosophila melanogaster) in Current Biology. This article by Long, Agrawal and Rowe does also have some important implications for what kind of inferences that can be made to natural populations based on studies in laboratory settings, with a cautionary tale.

Time and place as usual: "Argumentet "(2nd floor, Ecology Building) at 10.30, Tuesday, February 5.

Below, you will find Abstract and link to the article.

The Effect of Sexual Selection on Offspring Fitness Depends on the Nature of Genetic Variation

• Tristan A.F. Long^1, 2, , , 
• Aneil F. Agrawal¹, 
• Locke Rowe¹

• ¹ Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
• ² Department of Biology, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada

• http://dx.doi.org.ludwig.lub.lu.se/10.1016/j.cub.2011.12.020, How to Cite or Link Using DOI

• Permissions & Reprints

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Summary

Whether the changes brought about by sexual selection are, on the whole, congruent or incongruent with the changes favored by natural selection is a fundamentally important question in evolutionary biology. Although a number of theoretical models have assumed that sexual selection reinforces natural selection [1 and 2], others assume these forces are in opposition [3, 4 and 5]. Empirical results have been mixed (see reviews in [1, 6, 7 and 8]) and the reasons for the differences among studies are unclear. Variable outcomes are expected if populations differ in their evolutionary histories and therefore harbor different amounts and types of segregating genetic variation. Here, we constructed populations of Drosophila melanogaster that differed in this regard to directly test this hypothesis. In well-adapted populations, sexually successful males sired unfit daughters, indicating sexual and natural selection are in conflict. However, in populations containing an influx of maladaptive alleles, attractive males sired offspring of high fitness, suggesting that sexual selection reinforces natural selection. Taken together, these results emphasize the importance of evolutionary history on the outcome of sexual selection. Consequently, studies based on laboratory populations, cultured for prolonged periods under homogeneous conditions, may provide a skewed perspective on the relationship between sexual and natural selection.

New logo and some words about our visitor statistics and blog impact

Posted by Erik Svensson

Our blog continues to attract many outside readers, since it was first launched some years ago. We have had aobut 93 000 downloads, although all not unique ones, and although some come from automatic web searches and machines, I still think that we can safely conclude that we have had thousands of human visitors. The number of downloads is currently about 1000 per month, which is a decline from about 7000 per month, before we changed the name and adress of the blog in August 2012. However, this cost in terms of lost visitors will probably be worth it in the long term, as we have a steady increase in visitors and the blog name is now more general and less person-centred.

Interestingly, the currently most popular and visited blog post of ours is the one where our new postdoc Lesley Lancaster was introduced to the other lab-members. This blog post has 1007 visits, which makes me wonder if Lesley is more famous and more popular than a post about Richard Dawkins who is number two, with only 845 downloads? Clearly, Lesley is a more up-and-coming scientist though, than Richard Dawkins who has passed his peak a long time ago. 

I have gotten many positive comments from colleagues from outside, as well as putative postdocs and PhD-students who have expressed interest in joining this laboratory. Several have also said that the combination of  laboratory experimental evolution approaches (flatworms and Drosophila) and field experimental work on non-classical model organisms (damselflies, lizards, birds) is a powerful and attractive combination. The new logo above should hopefully capture this synthetic spirit of our research laboratory. Below, you can download the new header of our blog and use as a logo if you wish, or promote us to interested collegues.