Fig. 6
From: Iridescence and hydrophobicity have no clear delineation that explains flower petal micro-surface
Green contrast calculated from reflectance spectra obtained at different bisector angles for the tip and bottom petal regions of A. huegelii (a and b, respectively) and the lateral sepal of T. majus (c), assuming different illuminations: open sky during midday in the northern hemisphere, CIE D65 (blue line), forest and woodland shade (green and brown lines), small gaps (yellow line) and cloudy condition (black line). Dashed grey line represent the green contrast threshold value required for detection of small targets by honeybees [30] (see text for details). As green contrast values for our samples are always below the detection threshold for all illumination conditions considered, it may be concluded that changes in total intensity for our samples are not likely to be perceivable by honeybees under most common natural ambient illuminations.
