The ecotype paradigm: testing the concept in an ecologically divergent grasshopper
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© 2016 by Koninklijke Brill NV, Leiden, The Netherlands. Schistocerca lineata is a widely distributed species found throughout North America, which is known to be highly variable and displays high levels of local host plant association, with four known ecotypes. Here, we test the hypothesis that the ecotype designation corresponds to genetic differentiation using molecular and morphological data by studying eight populations representing all ecotypes. Three size-dependent measures and one size-independent measure of morphology were used to evaluate phenotypic differences between populations, but these traits varied too greatly within populations and ecotypes to determine a signal of divergence. A phylogeographic analysis was unable to detect a robust signal of population-level genetic divergence. We provide evidence for a single distinct ecotype with a unique feeding habit that is genetically differentiated from all other ecotypes, suggesting that the other ecotype designations may not represent true evolutionary trajectories. Our work illustrates the need for robust molecular data when attempting to define ecotypes.
author list (cited authors)
Raszick, T. J., & Song, H.