Ecological, morphological and genetic divergence of sympatric North Atlantic killer whale populations

Andrew David Foote, James Newton, Stuart Brannon Piertney, Eske Willerslev, M. Thomas P. Gilbert

Research output: Contribution to journalArticle

115 Citations (Scopus)

Abstract

Ecological divergence has a central role in speciation and is therefore an important source of biodiversity. Studying the micro-evolutionary processes of ecological diversification at its early stages provides an opportunity for investigating the causative mechanisms and ecological conditions promoting divergence. Here we use morphological traits, nitrogen stable isotope ratios and tooth wear to characterize two disparate types of North Atlantic killer whale. We find a highly specialist type, which reaches up to 8.5 m in length and a generalist type which reaches up to 6.6 m in length. There is a single fixed genetic difference in the mtDNA control region between these types, indicating integrity of groupings and a shallow divergence. Phylogenetic analysis indicates this divergence is independent of similar ecological divergences in the Pacific and Antarctic. Niche-width in the generalist type is more strongly influenced by between-individual variation rather than within-individual variation in the composition of the diet. This first step to divergent specialization on different ecological resources provides a rare example of the ecological conditions at the early stages of adaptive radiation.

Original languageEnglish
Pages (from-to)5207-5217
Number of pages11
JournalMolecular Ecology
Volume18
Issue number24
Early online date16 Dec 2009
DOIs
Publication statusPublished - Dec 2009

Keywords

  • Atlantic
  • ecotype
  • killer whale
  • Orcinus orca
  • Phylogenetics
  • persistent organic pollutants
  • orcinus-orca
  • reproductive isolation
  • feeding ecology
  • phylogenetic trees
  • adaptive radiation
  • mitochondrial-DNA
  • British-Columbia
  • stable-isotope
  • speciation

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