Shifting habitats, morphology, and selective pressures: Developmental polyphenism in an adaptive radiation of Hawaiian spiders

Particularly intriguing examples of adaptive radiation are those in which lineages show parallel or convergent evolution, suggesting utilization of similar genetic or developmental pathways. The current study focuses on an adaptive radiation of Hawaiian "spinyleg" spiders in which diversif...

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Bibliographic Details
Published in:Evolution 2015-01, Vol.69 (1), p.162-178
Main Authors: Brewer, Michael S., Carter, Rebecca A., Croucher, Peter J. P., Gillespie, Rosemary G.
Format: Article
Language:English
Subjects:
Adaptation
Adaptation, Physiological
Adaptive radiation
Amino acids
Animals
Araneae
Biological taxonomies
color
ecomorph
Ecosystem
Evolution
Evolution, Molecular
Genetic loci
Genetic Speciation
Genetic Variation
Habitats
heterochrony
Morphology
natural selection
Nucleotides
Phylogeny
Pigmentation
Pigments
Pressure
Radiation
Selection, Genetic
Spiders
Spiders - genetics
Spiders - metabolism
Taxa
Tetragnatha
Transcriptome
transcriptomics
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Summary:Particularly intriguing examples of adaptive radiation are those in which lineages show parallel or convergent evolution, suggesting utilization of similar genetic or developmental pathways. The current study focuses on an adaptive radiation of Hawaiian "spinyleg" spiders in which diversification is associated with repeated convergent evolution leading to similar sets of ecomorphs on each island. However, two species on the oldest islands in the archipelago exhibit variability, occurring as two different ecomorphs. More derived species on the younger islands show much less variability, any one species displaying a single ecomorph. We measured ecomorphological features within individuals over time to determine the nature of the variability. Then, using transcriptomes, we conducted lineage-based tests for selection under varying models and analyses of gene tree versus species tree incongruencies. Our results provide strong evidence that variability in color in Tetragnatha kauaiensis and T. polychromata is associated with development within individuals (polyphenism). Moreover, a total of 28 loci showed a signature of selection associated with loss of the color-changing phenotype, and 37 loci showed a signature of selection associated with the colonization of a new environment. The results illustrate how developmental polyphenism might provide an avenue for the repeated evolution of ecomorphs during adaptive radiation.
ISSN:0014-3820
1558-5646
DOI:10.1111/evo.12563