Lab-meeting on March 16 2011. New paper on condition-dependent sexual signalling by exiled lab-member Tom Gosden

Next week's lab-meeting we will not read any paper, but instead Machteld Verzijden and myself will give some informal presentations of the talks we will give in a small symposium on insect behaviour and evolution in Stockholm on Thursday, that is arranged by Professor Christer Wiklund in conjunction with a PhD-defence by his student Martin Bergman. Both Machteld and I will of course be happy for any feedback you might have, the day before our official presentations. The title of Machtelds talk is "Ethological speciation mechanisms" and mine is "Ecological vs. non-ecological speciation mechanisms".

If you nevertheless have time and are interested in reading a cool paper, there is one good one that has just been published in Journal of Evolutionary Biology by Tom Gosden and Steve Chenoweth. As you know, Tom is currently in exile in Australia, funded by a Marie Curie "outgoing" postdoc, where he now studies the fascinating and charismatic fruitfly Drosophila serrata, which has recently emerged as somewhat of a model organism in evolutionary quantitative genetics and sexual selection studies. Steve Chenoweth and Mark Blows are leading researchers in this field and have developed sophisticated statistical techniques to estimate breeding values and selection on such breeding values in this species.

The present study tests assumptions behind so-called "genic capture"-model of sexual selection, by looking at the degree of condition-dependence and genetic variation for in condition-dependence among males of Drosophila serrata in relation to a novel food source (yeast). Interestingly, the authors found evidence for condition-dependent sexual signalling, but apparently no genetic variation for condition-dependence, which indicates that it cannot evolve further, at least on this food source. Beware of some heavy maths and statistitics, before you decide to read this paper! Tom will return to Lund in 2012 (same year as Yuma) and bring in fresh new knowledge and skills to our group that he learned in Australia. Below is the abstract of their fascinating paper:

On the evolution of heightened condition dependence of male sexual displays

T. P. GOSDEN & S. F. CHENOWETH

The maintenance of genetic variation in male sexual display traits in the face of strong directional sexual selection from female preferences is an ongoing evolutionary conundrum. Condition dependence and the genic capture hypothesis are often cited as theoretical resolutions to this problem, yet little is known about the ability of condition dependence itself to evolve. We set out to test how a suite of cuticular hydrocarbons (CHCs) used in sexual displays are affected by adult diet and the potential for any condition-dependent response to evolve in a laboratory-adapted population of the Australian fruit fly Drosophila serrata. We performed a dietary manipulation within a half-sib breeding design, raising adult males either with or without access to live yeast, a manipulation that had previously shown strong effects on female fitness. Diet had strong phenotypic effects, with males from the different diets producing different CHC blends. The blend of CHCs under sexual selection showed a degree of elevated condition dependence. Regardless of the heightened sensitivity of favoured CHC blends to diet and the presence of genetic variance for the traits, we were unable to detect any genetic variance in the reaction norms for the male dietary response. Our results suggest that there is limited opportunity for males to evolve further condition dependence in response to yeast availability in this population.

New PhD-thesis in the lab: Fabrice Eroukhmanoff

I am pleased to announce that a new PhD-thesis will now be defended in our group: Fabrice Eroukhmanoff's Magnum Opus "The interplay Between Selection and Constraints on adaptive Divergence and Phenotypic Evolution".

This is the third Ph.D.-student that has finished his/her thesis in our lab, the previous two were Jessica Abbott (2006) and Tom Gosden (2008). You can find an abstract and more informaton about the thesis here. Well done Fabrice!

The thesis will be defended on Friday November 20 in the Blue Hall (Ecology Building). The external opponent will be Professor Andrew Hendry from McGill University Canada, and the thesis committé will consist of Professors Anna Qvarnström (Uppsala University), Karin Rengefors (Limnology, Lund University) and Janne S. Kotiaho (University of Jyväskylä, Finland). The thesis defence is open to everyone, and I encourage you to participate in this exciting event.

Lab-meeting on G-matrix divergence i isopods

This coming Wednesday (16 September), we will discuss genetic correlations and G-matrices in aquatic isopods (Asellus aquaticus). It is a manuscript that Fabrice and I have worked on for quite a while now, and which is one of the papers in his Ph.D.-thesis that he will defend on November 20. Naturally, we would appreciate all constructive input and criticisms so that we can incorporate these before Fabrice will handle in his thesis to the printer on October 20.

This manuscript which deals with morphological variation and quantiative genetics of morphology, should also be of interest to Tina and Sanna, who have been working recently on phenotypic and genetic correlations of behavioural traits in these isopods.

You can get this manuscript by e-mailing me (erik.svensson@zooekol.lu.se) or Fabrice (fabrice.eroukhmanoff@zooekol.lu.se). If Fabrice sends me the last version, I will also send out this manuscript to the group tomorrow (Monday).

Time and place as usual: "Darwin-room" at 10.00 on Wednesday 16 September. Any fika volunteer?