Data from: Sexual signals for the colour-blind: cryptic female mantids signal quality through brightness

1. Cryptic coloration may evolve in response to selective pressure imposed by predators, yet effective intraspecific communication may require some level of detectability. This creates a tension between the benefits of sexually selected visual traits and the predatory costs imposed by greater conspicuousness, and little is known about how this tension may be ameliorated in highly cryptic species. 2. We explore these competing demands in the false garden mantid Pseudomantis albofimbriata, a colour-blind and seemingly cryptic insect. We use reflectance spectrometry and receptor-noise modelling to characterize the conspicuousness of mantid body regions in the visual systems of mates (mantids), as well as potential predators (birds) and prey (bees). We then use condition manipulation and conspecific choice tests to further explore the colour traits of interest. 3. Based on visual modelling, we find that male mantids are inconspicuous to conspecifics, prey and predators – that is, they are chromatically and achromatically cryptic. In contrast, female mantids are chromatically cryptic to all potential receivers, but their abdomens are achromatically conspicuous. Our food manipulation experiment shows that females in good condition (and therefore with more eggs) have brighter abdomens than females in poor condition. Choice assays show male mantids are consistently attracted to females bearing brighter abdomens. 4. Our results reveal brightness-mediated sexual signalling in a colour-blind and classically cryptic insect. By communicating in the only visual channel available to them, female mantids are conspicuously signalling their quality to mates, while potentially minimizing their conspicuousness to predators and prey. Furthermore, by signalling with only a single body region, female mantids are apparently using coincident disruptive coloration to further decrease detectability to potential eavesdroppers. 5. Our data reveal a novel example of the way in which the trade-off between sexual selection for conspicuousness and natural selection for crypsis may be mediated in a visual signalling system. Such signals may be common in apparently cryptic species, and this study once again demonstrates the importance of analysing visual signals beyond the capacity of human vision.

Usage Notes
Choice testsData from conspecific choice experimentchoice_tests.csvCondition and brightnessData from female condition/brightness experimentcondition_brightness.csvVisual modellingData from visual modelling of mantid body regionsvisual_modelling.csv

1. 暗色伪装可能因捕食者施加的选择压力而进化，然而，有效的种内沟通可能需要一定程度的可检测性。这在一方面是性选择视觉特征的益处与由于更高显眼性带来的捕食成本之间的紧张关系，另一方面，关于这种紧张关系如何在高度伪装的物种中得到缓解，了解甚少。
2. 我们以假花园螳螂 Pseudomantis albofimbriata 为例，探讨这些相互竞争的需求，该螳螂是一种色盲且看似伪装的昆虫。我们运用反射光谱学和受体噪声建模技术，对螳螂体表区域在配偶（螳螂）以及潜在的捕食者（鸟类）和猎物（蜜蜂）的视觉系统中的显眼性进行表征。随后，我们通过条件操控和同种选择测试进一步探索感兴趣的色彩特征。
3. 基于视觉建模，我们发现雄性螳螂对同种个体、猎物和捕食者均不显眼——也就是说，它们在色度和无色度上均具伪装性。相比之下，雌性螳螂对所有可能的接收者均呈现色度伪装，但它们的腹部在无色度上却显眼。我们的食物操控实验显示，处于良好状态（因此拥有更多卵）的雌性螳螂腹部颜色比状态较差的雌性螳螂更亮。选择实验表明，雄性螳螂持续被携带更亮腹部颜色的雌性所吸引。
4. 我们的研究揭示了在一种色盲且传统上伪装的昆虫中，亮度介导的性信号。通过仅利用他们可用的唯一视觉通道进行沟通，雌性螳螂显著地向配偶传递其质量信号，同时可能最大限度地减少对捕食者和猎物的显眼性。此外，通过仅利用单一体表区域进行信号传递，雌性螳螂似乎在使用协同破坏性色彩来进一步降低对潜在窃听者的可检测性。
5. 我们的数据揭示了在视觉信号系统中，性选择对显眼性与自然选择对伪装之间的权衡可能如何得到调节的全新实例。此类信号在看似伪装的物种中可能普遍存在，而本研究再次证明了分析超出人类视觉能力的视觉信号的重要性。
Usage Notes
选择测试：同种选择实验数据
condition_brightness.csv：条件和亮度数据
视觉建模：螳螂体表区域视觉建模数据
visual_modelling.csv