Open AccessEcological speciation in postglacial E uropean whitefish: rapid adaptive radiations into the littoral, pelagic, and profundal lake habitats
Author(s) -
Præbel Kim,
Knudsen Rune,
Siwertsson Anna,
Karhunen Markku,
Kahilainen Kimmo K.,
Ovaskainen Otso,
Østbye Kjartan,
Peruzzi Stefano,
Fevolden SveinErik,
Amundsen PerArne
Publication year - 2013
Publication title -
ecology and evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.17
H-Index - 63
ISSN - 2045-7758
DOI - 10.1002/ece3.867
Subject(s) - profundal zone , allopatric speciation , sympatric speciation , ecology , biology , pelagic zone , sympatry , littoral zone , ecological speciation , ecological niche , trophic level , adaptive radiation , character displacement , habitat , phylogenetic tree , genetic variation , population , gene flow , biochemistry , demography , sociology , gene
Abstract Understanding how a monophyletic lineage of a species diverges into several adaptive forms has received increased attention in recent years, but the underlying mechanisms in this process are still under debate. Postglacial fishes are excellent model organisms for exploring this process, especially the initial stages of ecological speciation, as postglacial lakes represent replicated discrete environments with variation in available niches. Here, we combine data of niche utilization, trophic morphology, and 17 microsatellite loci to investigate the diversification process of three sympatric E uropean whitefish morphs from three northern F ennoscandian lakes. The morphological divergence in the gill raker number among the whitefish morphs was related to the utilization of different trophic niches and was associated with reproductive isolation within and across lakes. The intralacustrine comparison of whitefish morphs showed that these systems represent two levels of adaptive divergence: (1) a consistent littoral–pelagic resource axis; and (2) a more variable littoral–profundal resource axis. The results also indicate that the profundal whitefish morph has diverged repeatedly from the ancestral littoral whitefish morph in sympatry in two different watercourses. In contrast, all the analyses performed revealed clustering of the pelagic whitefish morphs across lakes suggesting parallel postglacial immigration with the littoral whitefish morph into each lake. Finally, the analyses strongly suggested that the trophic adaptive trait, number of gill rakers, was under diversifying selection in the different whitefish morphs. Together, the results support a complex evolutionary scenario where ecological speciation acts, but where both allopatric (colonization history) and sympatric (within watercourse divergence) processes are involved.