Saturday, August 28, 2010

Contemplating speciation from Iceland.

Photo: Andrew Hendry contemplates Holar, where biologists contemplate speciation.

What better place to have a workshop on speciation than Iceland? This dynamic island has contributed so much to our modern understanding of how environmental differences can drive the evolution of reproductive isolation, so-called “ecological speciation”. As freshwater habitats were opened up following the last glaciation, Arctic char, threespine stickleback, and a few other fish species established new populations. These populations then adaptively radiated into new forms, most famously the four reproductively isolated types of Arctic char found in Thingvallavatn, the largest lake in Iceland.

On this inspiring Icelandic backdrop in the first week of August 2010 was held a speciation workshop at Holar University College (ww2.holar.is). The workshop was organized by Skuli Skulason, Ake Brannstrom, and Ulf Dieckmann under the aegis of FroSpects (www.iiasa.ac.at/Research/EEP/FroSpects/). Graciously hosted by Skuli, Bjarni Kristjansson, and their Holar colleagues, the workshop brought together dozens of speciation scientists from Europe and North America. Each person presented talks or posters in the auditorium under the watchful eye of 700 years of Holar bishops.

So what transpired? Many things were discussed, of course, and I can’t cover them all – nor would you wish to read it. So I have merely selected one topic that jumped out as being unresolved. A number of speakers presented theoretical arguments that phenotypic plasticity should promote ecological speciation – by allowing the colonization of new environments or the use of new resources. By contrast, a number of other speakers presented theoretical arguments that phenotypic plasticity should constrain ecological speciation – by reducing divergent selection on genotypes. Both sets of speakers could accept the basic points made by the other, and so we were left with no concrete conclusion about how plasticity ultimately influences ecological speciation.

This topic is likely to remain a hot one over the next few years. I am confident of this partly because it was one of the major points of late-night argument at Bjarni’s “beer club,” only a few years old and already a Holar institution. With the highest diversity of beer at any bar in Iceland – and even some single malt whisky on request – beer club may is becoming another Icelandic inspiration for speciation research. Move over Thingvallavatn.