Figure 5

Illustration of genetic variation in phenotypic plasticity of size when measured at different temperatures in three age classes in 18 latitudinal populations of six species of Coenagrion damselflies. Lines represent the best linear unbiased predictors (BLUPs) of family variance components for the height and slope of thermal reaction norms extracted from random regression models fitted with restricted maximum likelihood (REML). Different shades of gray separate data from the age of 42 days (black), 84 days (light gray) and 126 days (dark gray). The scales bars along the y-axes correspond to deviations from the population mean size at each age (in mm). The absolute position of each data series along the y-axis is arbitrary and was chosen to maximize readability. Differences in the slope and elevation within each data series corresponds to the amount of among-family genetic variability in reaction norms at that ontogenetic stage relative to the population mean reaction norm (see for example, Figure 3).