Polarimetry data, ImageJ/FIJI macros, R modeling code, and other data from: Approach trajectory and solar position affect host plant attractiveness to the small white butterfly
This data is a supplement to the manuscript "Approach trajectory and solar position affect host plant attractiveness to the small white butterfly". This manuscript used photo polarimetry to investigate differences in polarization among host and non-host plants of the polarization-sensitive small white butterfly, Pieris rapae. We also tested, and modelled, the effect of approach trajectory on the polarization of plant-reflected light and the resulting attractiveness to P. rapae. The abstract from the paper is quoted and reproduced below. The methods to produce this data are fully described in the associated manuscript or relate to macros within the dataset. These dataset contains (1) polarimetry data and example images, (2) the ImageJ/FIJI macros used to process the images and extract the polarimetry data, (3) R code used to model the effect of approach trajectory on polarization and the resulting attractiveness to P. rapae, and (4) miscellaneous supporting measurements. More detailed "read me.txt" files can be found in each subfolder. "While it is well documented that insects exploit polarized sky light for navigation, their use of reflected polarized light for object detection has been less well studied. Recently, we have shown that the small white butterfly, Pieris rapae, distinguishes between host and non-host plants based on the degree of linear polarization (DoLP) of light reflected from their leaves. To determine how polarized light cues affect host plant foraging by female P. rapae across their entire visual range including the ultraviolet (300-650 nm), we applied photo polarimetry demonstrating large differences in the DoLP of leaf-reflected light among plant species generally and between host and non-host plants specifically. As polarized light cues are directionally dependent, we also tested, and modelled, the effect of approach trajectory on the polarization of plant-reflected light and the resulting attractiveness to P. rapae. Using photo polarimetry measurements of plants under a range of light source and observer positions, we reveal several distinct effects when polarized reflections are examined on a whole-plant basis rather than at the scale of pixels or of entire plant canopies. Most notably from our modeling, certain approach trajectories are optimal for foraging butterflies, or insects generally, to discriminate between plant species on the basis of the DoLP of leaf-reflected light."