Convergent evolutionary processes driven by foraging opportunity in two sympatric morph pairs of Arctic charr with contrasting post-glacial origins

Monica V. Garduno-Paz, Colin E. Adams, Eric Verspoor, David Knox, Chris Harrod

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


The expression of two or more discrete phenotypes amongst individuals within a species (morphs) provides multiple modes upon which selection can act semi-independently, and thus may be an important stage in speciation. In the present study, we compared two sympatric morph systems aiming to address hypotheses related to their evolutionary origin. Arctic charr in sympatry in Loch Tay, Scotland, exhibit one of two discrete, alternative body size phenotypes at maturity (large or small body size). Arctic charr in Loch Awe segregate into two temporally segregated spawning groups (breeding in either spring or autumn). Mitochondrial DNA restriction fragment length polymorphism analysis showed that the morph pairs in both lakes comprise separate gene pools, although segregation of the Loch Awe morphs is more subtle than that of Loch Tay. We conclude that the Loch Awe morphs diverged in situ (within the lake), whereas Loch Tay morphs most likely arose through multiple invasions by different ancestral groups that segregated before post-glacial invasion (i.e. in allopatry). Both morph pairs showed clear trophic segregation between planktonic and benthic resources (measured by stable isotope analysis) but this was significantly less distinct in Loch Tay than in Loch Awe. By contrast, both inter-morph morphological and life-history differences were more subtle in Loch Awe than in Loch Tay. The strong ecological but relatively weak morphological and life-history divergence of the in situ derived morphs compared to morphs with allopatric origins indicates a strong link between early ecological and subsequent genetic divergence of sympatric origin emerging species pairs. The emergence of parallel specialisms despite distinct genetic origins of these morph pairs suggests that the effect of available foraging opportunities may be at least as important as genetic origin in structuring sympatric divergence in post-glacial fishes with high levels of phenotypic plasticity. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012
Original languageEnglish
Pages (from-to)794-806
Number of pages13
JournalBiological Journal of the Linnean Society
Issue number4
Publication statusPublished - Aug 2012


  • alternative phenotypes
  • discrete morphological variation
  • ecological segregation
  • foraging specialism
  • speciation


Dive into the research topics of 'Convergent evolutionary processes driven by foraging opportunity in two sympatric morph pairs of Arctic charr with contrasting post-glacial origins'. Together they form a unique fingerprint.

Cite this