Morphological divergences and ecological correlates among wild populations of zebrafish (Danio rerio)

• Published in: Environmental biology of fishes 2017-03, Vol.100 (3), p.251-264
• Main Authors: Shukla, Rohitashva, Bhat, Anuradha
• Format: Article
• Language: English
• Subjects: Adaptive radiation; Animal populations; Animal Systematics/Taxonomy/Biogeography; Biomedical and Life Sciences; Body size; Danio rerio; Dissolved oxygen; Environment; Fish; Freshwater; Freshwater & Marine Ecology; Genetic diversity; Genotype & phenotype; Life Sciences; Morphology; Nature Conservation; Phenotypic variations; Population genetics; Predators; Speciation; Zoology
• ISSN: 0378-1909; 1573-5133
• DOI: 10.1007/s10641-017-0576-3

Studies on morphological differences among populations from different ecological regions help towards understanding diversification of traits and is a fundamental step in adaptive radiation and ultimately, speciation. This study investigates the occurrence of variations in morphological traits among wild populations of zebrafish ( Danio rerio ) from India that inhabit a variety of habitat and ecological regimes. Geometric morphometric methods and traditional morphometric analysis were used to quantify the extent of differences in morphological traits between four populations of wild D. rerio from still-water (stagnant) (Kalibazaar, in West Bengal) and slow -medium flowing (Asan, Kaushalya and Seripetkalwa in Uttarakhand, Haryana and Andhra Pradesh respectively) habitats within India. Multivariate analyses showed significant effect of populations on morphology, post-hoc paired comparisons between populations show differences in body size as well as shape across these populations. Relative warps analyses on the landmarks selected for body shape showed higher loadings for caudal peduncle, head and eye regions. Population-wise scatterplots along relative warp1 (RW1)- relative warp4 (RW4) axes revealed Asan population cluster expands beyond the other population clusters along the RW1- RW2 axes, while the Kalibazaar cluster spreads out from the others along the RW3-RW4 axes. Multiple regression models to predict relation between shape and ecological attributes indicate the strongest role of dissolved oxygen, stream velocity and abundance of predators in explaining variations in morphology across these populations. This is significant as a first study utilising the tools of morphometric analyses in Danio rerio and indicating the role of multiple (biotic and abiotic) selective forces in shaping phenotypic variations in morphology.