lab-meeting on February 23 2011: On speciation and species concepts

The topic of this week's announced lab-meeting has been changed, since the manuscripts that were announced were apparently not ready. Instead, we'll discuss two papers that deal with the evolution of premating isolation and species concepts, respectively. Both are published in Evolution, and they can be downloade here and here.

Time and place as usual: "Darwin" at 13.30-15.00 (Wednesday February 23 2011). Tina will bring fika.
Below are the paper titles, the authors and the Abstracts:

MATE PREFERENCE ACROSS THE SPECIATION CONTINUUM IN A CLADE OF MIMETIC BUTTERFLIES 

Richard M. Merrill, Zachariah Gompert, Lauren M. Dembeck, Marcus R. Kronforst, W. Owen McMillan & Chris D. Jiggins 

Premating behavioral isolation is increasingly recognized as an important part of ecological speciation, where divergent natural selection causes the evolution of reproductive barriers. A number of studies have now demonstrated that traits under divergent natural selection also affect mate preferences. However, studies of single species pairs only capture a snapshot of the speciation process, making it difficult to assess the role of mate preferences throughout the entire process. Heliconius butterflies are well known for their brightly colored mimetic warning patterns, and previous studies have shown that these patterns are also used as mate recognition cues. Here, we present mate preference data for four pairs of sister taxa, representing different stages of divergence, which together allow us to compare diverging mate preferences across the continuum of Heliconius speciation. Using a novel Bayesian approach, our results support a model of ecological speciation in which strong premating isolation arises early, but continues to increase throughout the continuum from polymorphic populations through to “good,” sympatric ecologically divergent species.
 

PROGRESS TOWARD A GENERAL SPECIES CONCEPT

Bernhard Hausdorf

New insights in the speciation process and the nature of “species” that accumulated in the past decade demand adjustments of the species concept. The standing of some of the most broadly accepted or most innovative species concepts in the light of the growing evidence that reproductive barriers are semipermeable to gene flow, that species can differentiate despite ongoing interbreeding, that a single species can originate polyphyletically by parallel evolution, and that uniparental organisms are organised in units that resemble species of biparental organisms is discussed. As a synthesis of ideas in existing concepts and the new insights, a generalization of the genic concept is proposed that defines species as groups of individuals that are reciprocally characterized by features that would have negative fitness effects in other groups and that cannot be regularly exchanged between groups upon contact. The benefits of this differential fitness species concept are that it classifies groups that keep differentiated and keep on differentiating despite interbreeding as species, that it is not restricted to specific mutations or mechanisms causing speciation, and that it can be applied to the whole spectrum of organisms from uni- to biparentals.

Lab-meeting: "The biology of speciation"

This coming week, I was thinking that we should discuss a thought-provoking article entitled "The biology of speciation", published in Evolution early this year (2010). One of the authors is well-known plant evolutionary biologist Douglas Schemske, a strong naturalist and deep thinker. This article takes a critical look at the concept of "ecological speciation", and questions the usefulness of this term, since ecology is more or less involved in most speciation events. Instead, the authors argues that Ernst Mayr's term "Biological speciation" is more useful. I hope you will enjoy this paper and that we will have some thoughtful discussions about it. Ecological speciation has been taken so much for granted the last decade, so it is certainly time to critically question its importance and ask if its role has been exaggerated.

Time and place as usual: "Darwin", 2nd floor, Ecology Building on Wednesday March 17 (10.15).

Any "fika" volunteer???