Data from: Boundary Strength Analysis: combining colour pattern geometry and coloured patch visual properties for use in predicting behaviour and fitness

1.Colour patterns are used by many species to make decisions that ultimately affect their Darwinian fitness. Colour patterns consist of a mosaic of patches that differ in geometry and visual properties. Although traditionally pattern geometry and colour patch visual properties are analysed separately, these components are likely to work together as a functional unit. Despite this, the combined effect of patch visual properties, patch geometry, and the effects of the patch boundaries on animal visual systems, behaviour and fitness are relatively unexplored.

2.Here we describe Boundary Strength Analysis (BSA), a novel way to combine the geometry of the edges (boundaries among the patch classes) with the receptor noise estimate (ΔS) of the intensity of the edges. The method is based upon known properties of vertebrate and invertebrate retinas. The mean and SD of ΔS (mΔS, sΔS) of a colour pattern can be obtained by weighting each edge class ΔS by its length, separately for chromatic and achromatic ΔS. This assumes those colour patterns, or parts of the patterns used in signalling, with larger mΔS and sΔS are more stimulating and hence more salient to the viewers. BSA can be used to examine both colour patterns and visual backgrounds.

3.BSA was successful in assessing the estimated conspicuousness of colour pattern variants in two species, guppies (Poecilia reticulata) and Gouldian finches (Erythrura gouldiae), both polymorphic for patch colour, luminance and geometry. 3D representations of the ΔS of patch edges (Fort Diagrams) of both species show that there is little or negative geometric correspondence between the chromatic and achromatic edges. All individuals have mΔS > 1.5 for both chromatic and achromatic measures, indicating the high within‐pattern contrast expected for display signals. In contrast from what one would expect from sexual selection, all guppies have mΔS less than expected from random contacts between all pairs of patch colour/luminance classes. The correlation between chromatic and luminance ΔS is negative in both species but zero when correlating all possible kinds of edges between the colours of each species and morph indicating non‐random colour geometry.

4.The pattern difference between chromatic and achromatic edges in both species reveals the possibility that chromatic and achromatic edges could function differently. The smaller than random expected mΔS values in guppies suggests an anti‐predator function because guppies are never found without predators. Moreover, mΔS could vary with predation intensity within and among species. BSA can be applied to any colour pattern used in intraspecific and interspecific behaviour. Seven predictions and four questions about colour patterns are presented.

5.In species which are very convex, both chromatic and luminance mΔS change with viewing angle; geometry of signalling is as important as signal geometry.

1. 许多物种会利用色彩图案做出最终影响其达尔文适合度（Darwinian fitness）的决策。色彩图案由几何特征与视觉属性各不相同的斑块镶嵌而成。传统研究中，研究者往往单独分析图案几何特征与斑块视觉属性，但二者大概率作为功能整体协同发挥作用。尽管如此，斑块视觉属性、斑块几何特征，以及斑块边界对动物视觉系统、行为与适合度的综合影响，仍未得到充分探索。
2. 本研究介绍一种名为边界强度分析（Boundary Strength Analysis, BSA）的新方法，该方法可将斑块类群间边缘（即斑块边界）的几何特征，与边缘强度的受体噪声估测值（ΔS）相结合。该方法基于脊椎动物与无脊椎动物视网膜的已知特性。通过按长度对每类边缘的ΔS进行加权，可分别计算色彩通道与无色彩通道下ΔS的均值与标准差（记为mΔS、sΔS）。这一分析的前提是，具有更高mΔS与sΔS的色彩图案（或用于信号传递的图案部分）对接收者而言更具刺激性，因而更为醒目。BSA可用于分析色彩图案与视觉背景。
3. BSA已成功用于评估两个物种的色彩图案变体的表观显著性：孔雀鱼（Poecilia reticulata）与胡锦雀（Erythrura gouldiae），二者均在斑块色彩、明度与几何特征上存在多态性。对两个物种的斑块边缘ΔS的三维可视化表示（福特图，Fort Diagrams）显示，色彩边缘与无色彩边缘间几乎不存在几何对应性，或呈负相关。所有个体的色彩通道与无色彩通道mΔS均大于1.5，这符合信号展示预期的高图案内对比度。与性选择的预期相反，所有孔雀鱼的mΔS均低于所有斑块色彩/明度类群间随机配对接触的预期值。两个物种的色彩ΔS与明度ΔS均呈负相关，但在关联各物种不同色彩形态间所有可能的边缘类型时，相关性为零，这表明色彩几何特征并非随机分布。
4. 两个物种的色彩边缘与无色彩边缘间的模式差异，提示二者可能发挥不同功能。孔雀鱼的mΔS低于随机预期值，这暗示其具有反捕食功能，因为孔雀鱼的生存始终伴随捕食者压力。此外，mΔS可能随物种内部与物种间的捕食强度变化而改变。BSA可应用于种内与种间行为中使用的任意色彩图案。本研究提出了七条关于色彩图案的预测与四个研究问题。
5. 对于具有极强凸面形态的物种，色彩通道与明度通道的mΔS均会随观察角度变化而改变，这说明信号传递的几何特征与信号本身的几何特征同等重要。