†Present address: Queen’s University Belfast, School of Biological Sciences, Belfast, BT9 7BL, UK.
Phenotype-environment correlations in a putative whitefish adaptive radiation
Article first published online: 11 MAY 2010
© 2010 The Authors. Journal compilation © 2010 British Ecological Society
Journal of Animal Ecology
Volume 79, Issue 5, pages 1057–1068, September 2010
How to Cite
Harrod, C., Mallela, J. and Kahilainen, K. K. (2010), Phenotype-environment correlations in a putative whitefish adaptive radiation. Journal of Animal Ecology, 79: 1057–1068. doi: 10.1111/j.1365-2656.2010.01702.x
- Issue published online: 5 AUG 2010
- Article first published online: 11 MAY 2010
- Received 27 August 2009; accepted 7 April 2010 Handling Editor: Joseph Rasmussen
- ecological speciation;
- gill rakers;
- stable isotope analysis
1. The adaptive radiation of fishes into benthic (littoral) and pelagic (lentic) morphs in post-glacial lakes has become an important model system for speciation. Although these systems are well studied, there is little evidence of the existence of morphs that have diverged to utilize resources in the remaining principal lake habitat, the profundal zone.
2. Here, we tested phenotype-environment correlations of three whitefish (Coregonus lavaretus) morphs that have radiated into littoral, pelagic and profundal niches in northern Scandinavian lakes. We hypothesized that morphs in such trimorphic systems would have a morphology adapted to one of the principal lake habitats (littoral, pelagic or profundal niches). Most whitefish populations in the study area are formed by a single (monomorphic) whitefish morph, and we further hypothesized that these populations should display intermediate morphotypes and niche utilization. We used a combination of traditional (stomach content, habitat use, gill raker counts) and more recently developed (stable isotopes, geometric morphometrics) techniques to evaluate phenotype-environment correlations in two lakes with trimorphic and two lakes with monomorphic whitefish.
3. Distinct phenotype-environment correlations were evident for each principal niche in whitefish morphs inhabiting trimorphic lakes. Monomorphic whitefish exploited multiple habitats, had intermediate morphology, displayed increased variance in gillraker-counts, and relied significantly on zooplankton, most likely due to relaxed resource competition.
4. We suggest that the ecological processes acting in the trimorphic lakes are similar to each other, and are driving the adaptive evolution of whitefish morphs, possibly leading to the formation of new species.