Alpine insect biotas are frequently characterised by large numbers of wing-reduced species, but the ecological and evolutionary bases of this reductive evolution are poorly understood. We conduct phenotypic and genetic analyses of a wing-dimorphic New Zealand stonefly species to reveal increasing selection for a vestigial-winged phenotype with increasing altitude. Specifically, altitudinal transect sampling from two South Island streams reveals parallel increases in genotypic frequencies at a locus previously found to be associated with wing reduction in the Zelandoperla fenestrata complex. Strong clinal selection at this locus contrasts with genome-wide data from genotyping-by-sequencing. The concordant, steep clines observed at altitudes around 600-700 m in two neighbouring but phylogenetically-independent populations suggest that environmental gradients associated with exposure underpin this genetic and phenotypic diversity. Importantly, this study yields a highly novel example of ‘divergence with gene flow’ acting over fine spatial scales, illustrating that natural selection at one or a few genetic loci can potentially underpin dramatic cases of local adaptation in wild populations.
Alpine insect biotas are frequently characterised by large numbers of wing-reduced species, but the ecological and evolutionary bases of this reductive evolution are poorly understood. We conduct phenotypic and genetic analyses of a wing-dimorphic New Zealand stonefly species to reveal increasing selection for a vestigial-winged phenotype with increasing altitude. Specifically, altitudinal transect sampling from two South Island streams reveals parallel increases in genotypic frequencies at a locus previously found to be associated with wing reduction in the Zelandoperla fenestrata complex. Strong clinal selection at this locus contrasts with genome-wide data from genotyping-by-sequencing. The concordant, steep clines observed at altitudes around 600-700 m in two neighbouring but phylogenetically-independent populations suggest that environmental gradients associated with exposure underpin this genetic and phenotypic diversity. Importantly, this study yields a highly novel example of ‘divergence with gene flow’ acting over fine spatial scales, illustrating that natural selection at one or a few genetic loci can potentially underpin dramatic cases of local adaptation in wild populations.
2B9 - Building 2 GSA2018_APCC6 GSACC62018@canberra.edu.auTechnical Issues?
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