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Ecological, morphological and genetic divergence of sympatric North Atlantic killer whale populations
Author(s) -
FOOTE ANDREW D.,
NEWTON JASON,
PIERTNEY STUART B.,
WILLERSLEV ESKE,
GILBERT M. THOMAS P.
Publication year - 2009
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/j.1365-294x.2009.04407.x
Subject(s) - biology , sympatric speciation , generalist and specialist species , ecology , adaptive radiation , ecological speciation , divergence (linguistics) , genetic divergence , biodiversity , niche , evolutionary biology , phylogenetic tree , habitat , genetic variation , genetic diversity , population , gene , gene flow , biochemistry , linguistics , philosophy , demography , sociology
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.