Friday, November 19, 2010
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
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.
Thursday, September 30, 2010
Climatic niche similarity and geographic range limits in ecologically similar co-existing damselflies
Now it is time to discuss one of my papers again. Together with Keith Larson and Erik Svensson, I am currently working on a paper that investigates niche divergence in Calopteryx damselflies.
Speciation in the genus Calopteryx is largely thought to be de-coupled from ecology, and reproductive isolation seems to have evolved independent of habitat ecology, through sexual selection, social interactions, learning and/or genetic incompatibilities. For this reason, ecological differences between closely related odonates are a priori expected to be relatively minor, and the modest differences that exist are likely to have evolved post-speciation, reflecting ecological divergence after reproductive isolation was already achieved. We tested these predictions using a large habitat data set for the two largely co-existing species Calopteryx splendens and C. virgo in Sweden and Finland and then employed spatial modelling techniques to identify the:
(i) environmental habitat characteristics, amount of niche overlap and degree of habitat specialisation,
(ii) combined and interactive effects of environment and predators and
(iii) ecological differences between allopatric and sympatric populations.
It will be great to discuss our findings with you next week (as usual we meet on Wednesday the 6th of October at 10:15 at the Darwin room, Lund University). Erik has also suggested to read a recent paper by John E. McCormack, Amanda J. Zellmer, and L. Lacey Knowles. Their work focused on niche divergence and its role in speciation in Mexican Jays.
I will circulate the Evolution paper by McCormack et al. (2010) and the manuscript via email. If I have not included you in the email list and you would like to read and comment on these papers, then please send an email Maren.Wellenreuther@zooekol.lu.se
I will bring fika to the next meeting.
Have fun, Maren


