Environmental effects on genetic variance are likely to constrain adaptation in novel environments

Adaptive plasticity allows populations to cope with environmental variation but is expected to fail as conditions become unfamiliar. In novel conditions, populations may instead rely on rapid adaptation to increase fitness and avoid extinction. Adaptation should be fastest when both plasticity and selection occur in directions of the multivariate phenotype that contain abundant genetic variation. However, tests of this prediction from field experiments are rare. Here, we quantify how additive genetic variance in a multivariate phenotype changes across an elevational gradient, and test whether plasticity and selection align with genetic variation. We do so using two closely related, but ecologically distinct, sister species of Sicilian daisy (Senecio, Asteraceae) adapted to high and low elevations on Mount Etna. Using a paternal half-sibling breeding design, we generated and then reciprocally planted c.19,000 seeds of both species, across an elevational gradient spanning each species’ na..., All data was collected on seeds planted of two species at four elevations on Mt Etna, Sicily. Leaf pigment data was collected using a Dualex instrument (ForceA-France) and leaf morphology data was quantified from the software 'Lamina' that analyses scanned images of leaves., , # Environmental effects on genetic variance are likely to constrain adaptation in novel environments

These data are from a field experiment that planted seeds of two species of *Senecio* at four elevations on the slopes of Mt Etna, Sicily. Seeds were produced using a quantitative genetic breeding design with c.80 individuals of each species so that additive genetic variance could be estimated for all traits measured. Survival was used as a proxy for fitness, and leaf trait measurements include leaf morphology, size and pigment content.

## Description of the data file: Walter\_etal\_2024\_EvolutionLetters.csv

Below is a list of column identifiers in the .csv file. NA represent plants that died and could not be measured.

Columns A-H are plant identifiers.

* A: Species identifier.
* B: TGSite is the transplant elevation (500m, 1000m, 1500m and 2000m).
* C: PLANT is the individual ID for each plant.
* D: Block is the experimental block at each elevation.
* E: Family is the ...