Data from: The role of environment and core-margin effects on range-wide phenotypic variation of a montane grasshopper

The integration of genetic information with ecological and phenotypic data
constitutes an effective approach to gain insight into the mechanisms
determining interpopulation variability and the evolutionary processes
underlying local adaptation and incipient speciation. Here, we use the
Pyrenean Morales grasshopper (Chorthippus saulcyi moralesi) as study
system to (i) analyze the relative role of genetic drift and selection on
range-wide patterns of phenotypic differentiation and (ii) identify the
potential selective agents (environment, elevation) responsible for
variation. We also test the hypothesis that (iii) the development of
dispersal-related traits is associated with different parameters related
to population persistence/turnover, including habitat suitability
stability over the last 120 000 years, distance to the species
distribution core, and population genetic variability. Our results
indicate that selection shaped phenotypic differentiation across all the
studied morphological traits (body size, forewing length and shape).
Subsequent analyses revealed that among-population differentiation in
forewing length was significantly explained by a temperature gradient,
suggesting an adaptive response to thermoregulation or flight performance
under contrasting temperature regimes. We found support for our hypothesis
predicting a positive association between the distance to the species
distribution core and the development of dispersal-related morphology,
which suggests increased dispersal capability in populations located at
range edges that, in turn, exhibit lower levels of genetic variability.
Overall, our results indicate that range-wide patterns of phenotypic
variation are partially explained by adaptation in response to local
environmental conditions and differences in habitat persistence between
core and peripheral populations.