Site information
Samples were collected from plants growing in six regions in the Republic of Panama (Table 1; Fig. S1). We extracted mean, minimum, and maximum monthly temperatures for each study site from WorldClim 2.0 (Fick & Hijmans, 2017), which provides spatially interpolated monthly climate variables with an accuracy of ~1 km2. For the lowland sites additional climate data were available from the Physical Monitoring Program of the Smithsonian Tropical Research Institute, and from the Panama Canal Authority (Table S1). The WorldClim data correlated very well with the monitored data (R2 = 0.9. Table S1) and for consistency we used WorldClim data for all sites in the analyses.