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."

本数据集为论文《趋近轨迹与太阳位置影响寄主植物对菜粉蝶的吸引力（Approach trajectory and solar position affect host plant attractiveness to the small white butterfly）》的补充数据。该论文采用光偏振测量法（photo polarimetry），探究了对偏振敏感的菜粉蝶（Pieris rapae）的寄主与非寄主植物间的偏振特性差异。研究同时测试并建模了趋近轨迹对植物反射光偏振特性的影响，以及由此产生的对菜粉蝶的吸引力。以下引用并转载了该论文的摘要。本数据集的制作方法已在相关论文中完整阐述，或与数据集内的宏程序相关。本数据集包含：(1) 偏振测量数据与示例图像；(2) 用于处理图像并提取偏振测量数据的ImageJ/FIJI宏程序；(3) 用于建模趋近轨迹对偏振特性的影响、以及由此产生的对菜粉蝶吸引力的R代码；(4) 各类辅助支持测量数据。每个子文件夹中均包含更详细的"read me.txt"文件。

“已有充分研究证实，昆虫可利用天空偏振光进行导航，但它们利用反射偏振光开展物体检测的相关研究则相对不足。近期我们的研究表明，菜粉蝶（Pieris rapae）可依据叶片反射光的线偏振度（Degree of Linear Polarization, DoLP）区分寄主与非寄主植物。为探明偏振光信号如何在包括紫外波段（300-650 nm）在内的全视觉范围内影响雌性菜粉蝶的寄主觅食行为，我们采用光偏振测量法，发现不同植物物种的叶片反射光的线偏振度普遍存在显著差异，且寄主与非寄主植物之间的差异尤为明显。鉴于偏振光信号具有方向依赖性，我们进一步测试并建模了趋近轨迹对植物反射光偏振特性的影响，以及由此产生的对菜粉蝶的吸引力。通过对不同光源与观测位置下的植物进行光偏振测量，我们发现：当从整株植物层面而非像素或植物冠层尺度分析偏振反射时，会呈现出多种独特效应。从建模结果来看，最为显著的是，对于觅食中的蝴蝶或多数昆虫而言，特定的趋近轨迹可使其基于叶片反射光的线偏振度有效区分不同植物物种。”