Data from: Habitat disturbance alters color contrast and the detectability of cryptic and aposematic frogs

Animals use color both to conceal and signal their presence, with patterns that match the background, disrupt shape recognition, or highlight features important for communication. The forms that these color patterns take are responses to the visual systems that observe them and the environments within which they are viewed. Increasingly, however, these environments are being affected by human activity. We studied how pattern characteristics and habitat change may affect the detectability of three frog color patterns from the Bocas del Toro archipelago in Panama: Beige-Striped Brown Allobates talamancae and two spotted morphs of Oophaga pumilio, Black-Spotted Green and Black-Spotted Red. To assess detectability, we used visual modeling of conspecifics and potential predators, along with a computer-based detection experiment with human participants. Although we found no evidence for disruptive camouflage, we did find clear evidence that A. talamancae stripes are inherently more cryptic than O. pumilio spots regardless of color. We found no evidence that color pattern polytypism in O. pumilio is related to differences in the forest floor between natural sites. We did, however, find strong evidence that human disturbance affects the visual environment and modifies absolute and rank order frog detectability. Human-induced environmental change reduces the effectiveness of camouflage in A. talamancae, reduces detectability of Black-Spotted Green O. pumilio, and increases chromatic contrast, but not detectability, in Black-Spotted Red O. pumilio. Insofar as predators may learn about prey defenses and make foraging decisions based on relative prey availability and suitability, such changes may have wider implications for predator-prey dynamics.

动物借助色彩同时实现隐蔽与信号传递两类功能，其体表图案可通过匹配背景环境、干扰轮廓识别，或是凸显通讯所需的关键特征来达成上述目的。这类色彩图案的表现形式，是对感知该图案的视觉系统以及其所处观测环境的适应性响应。然而，当前此类环境正日益受到人类活动的干扰。本研究以巴拿马博卡斯德尔托罗群岛的三种蛙类色彩图案为研究对象，探究图案特征与栖息地变化对其可探测性的影响：分别为棕褐带纹的塔拉曼卡箭毒蛙（Allobates talamancae），以及草莓箭毒蛙（Oophaga pumilio）的两种斑点变型——黑斑绿型与黑斑红型。为评估可探测性，本研究采用了针对同种个体与潜在捕食者的视觉建模方法，同时结合了基于计算机平台的人类受试者探测实验。尽管未发现破坏性伪装的相关证据，但本研究明确证实，无论色彩如何，塔拉曼卡箭毒蛙的条纹天生比草莓箭毒蛙的斑点更具隐蔽性。本研究未发现草莓箭毒蛙的色彩图案多型性与自然生境间的林地表层差异存在关联。但本研究证实，人类干扰会显著改变视觉环境，并改变蛙类可探测性的绝对值与排序位次。人类活动引发的环境变化会降低塔拉曼卡箭毒蛙的隐蔽效果，削弱黑斑绿型草莓箭毒蛙的可探测性，并提升黑斑红型草莓箭毒蛙的色彩对比度，但并未改变其可探测性。鉴于捕食者可习得猎物的防御特性，并基于猎物相对可获得性与适宜性做出觅食决策，此类变化可能对捕食者-猎物动态产生更为广泛的影响。