Data from: A chorus of color: hierarchical and graded information content of rapid color change signals in chameleons

Animals rely on information-rich signals to minimize costs associated with competition. If fighting ability is linked to stable individual attributes (e.g. morphology), the signals that communicate information about such ability should be relatively static. Conversely, the temporal variability of motivation should favor dynamic threat signals that indicate an animal's likelihood of escalating a contest. Though static colors are used by many animals to signal quality or fighting ability, the function of dynamic color change as a social signal has only recently begun to be investigated. Here, we examined the information content of rapid physiological color changes displayed by adult male veiled chameleons Chamaeleo calyptratus during agonistic interactions by conducting experimental trials between live chameleons and standardized, experimentally-controlled robochameleon models. Chameleons reliably communicated motivation with dynamic color displays – individuals that brightened were 14 times more likely to approach the robochameleon than non-brightening individuals. Additionally, chameleons with shorter latencies to maximum stripe brightness had stronger bites, and those displaying brighter, yellower stripes exhibited more aggression. The parallels between dynamic color changes and the vocalizations used to mediate aggressive interactions in other taxa are numerous. The use of particular vocalizations/color changes can signal motivation levels while specific signal elements (e.g. pitch, timing, brightness) may be linked to fighting ability. Because the complexity and potential information content of color signals increases markedly when organisms can display context-specific variation in the expression of these ornaments, the study of dynamic color signals is a field ripe for the investigation of complex visual and signaling strategies.

动物依托富含信息的信号，以降低竞争相关的各类成本。若打斗能力与个体的稳定属性（如形态特征）存在关联，则传递此类能力信息的信号应相对静态。反之，动机的时间波动性则会偏好催生动态威胁信号，这类信号可传递动物升级争斗的可能性。尽管诸多动物会利用静态色彩传递自身质量或打斗能力的信息，但动态色彩变化作为社会信号的功能，直至近年才得到研究关注。本研究通过开展活体变色龙与标准化、实验可控的机器变色龙（robochameleon）模型的互动实验，探究了成年雄性高冠变色龙（Chamaeleo calyptratus）在争斗互动过程中展现出的快速生理性色彩变化所携带的信息内容。研究发现，变色龙可通过动态色彩展示可靠传递自身动机状态：体色变亮的个体接近机器变色龙模型的概率，是未变色个体的14倍。此外，条纹亮度达到峰值所需时长更短的变色龙，咬合力更强；而展现出更明亮、偏黄色条纹的个体则表现出更强的攻击性。动态色彩变化与其他分类群中用于调解争斗互动的发声行为之间，存在诸多相似之处：特定发声行为或色彩变化的使用可传递动机水平，而特定信号元素（如音调、时序、亮度）则可能与打斗能力相关联。由于当生物能够针对不同情境展现这类装饰性色彩表达的变异时，色彩信号的复杂性与潜在信息含量会显著提升，因此动态色彩信号的研究现已成为探究复杂视觉与信号传递策略的成熟领域。