Normalized surface temperature in relation to the relative distance from the flower center (0) to the outer edge (1) along a transect line under natural sunlight (red points) and artificial shade (gray points). Temperature is normalized as 0 for the minimum and 1 for the maximum along each of 5 or more transect lines in each flower or a flower unit. Curves within each plot are smoothed for all the data from 5 or more transect lines within a flower or a flower unit with 3–5 individual flowers for each species under respective light conditions using locally weighted regression.