DISSERTATION RESEARCH: The Function and Evolution of Rapid Color Change as a Social Signal

迄今为止，大多数关于视觉信号的研究都集中在动物的固定外观上，特别是它们的颜色。因此，从生态学、行为学和进化的角度来看，动态颜色信号仍然知之甚少。为了开始解决这种差异，研究人员先前对雄性面纱变色龙Chamaeleo calyptratus的快速颜色变化的控制和功能进行了详细的研究。然而，需要更广泛的背景来理解这些不寻常的颜色变化信号的进化起源和限制。在这项研究中，研究人员将对Bradypodion侏儒变色龙进行比较研究，以调查颜色变化信号是如何以及为什么进化的。侏儒变色龙在颜色变化和物种间的显示行为上表现出明显的变化，使它们成为测试这种罕见信号类型的起源和功能的进化假说的理想选择。本研究旨在确定颜色变化是否演变为强调行为显示（反之亦然），或出现作为一个信号独立于复杂的行为，并评估潜在的系统发育约束颜色变化。除了在科学期刊上交流研究结果外，研究人员还将与亚利桑那州立大学和南非国家生物多样性研究所的外展项目合作，通过为亚利桑那州和南非的中学生定制的学习活动分享主要研究成果。为了更好地了解复杂的行为显示是在复杂的颜色变化信号之前，之后还是同时进化的，研究人员将使用高清摄像机测量12种矮变色龙的种内行为（即攻击/顺从）和颜色信号的自然套件，以记录每个物种自然栖息地中同种之间的阶段性，攻击性相互作用。动物的静态照片，同时视频，将采取在侵略性的试验和比色数据将收集整个行为显示和快速颜色变化的发作。Felsenstein的独立对比和系统发育广义最小二乘（PGLS）分析将用于评估显示色度学和显示行为的多个方面之间的进化关系，并将评估所有颜色和行为信号的系统发育信号的强度。最后，该计划麦斯奎特将被用来重建祖先状态的行为显示和颜色信号，试图解开的顺序和模式的信号阐述。

To date, most studies on visual signals have focused on the fixed appearances of animals and, specifically, of their color. As a result, dynamic color signals remain poorly understood from ecological, behavioral, and evolutionary standpoints. To begin to address this discrepancy, the researchers previously conducted detailed studies of the control and function of rapid color change in male veiled chameleons, Chamaeleo calyptratus. However, a broader context is required to understand the evolutionary origins of and constraints on these unusual color change signals. In this study, the researchers will conduct a comparative study of Bradypodion dwarf chameleons to investigate how and why color change signals evolved. Dwarf chameleons exhibit marked variation in color change and display behavior among species, making them ideal for testing evolutionary hypotheses about the origin and function of this rare signal type. This study seeks to determine whether color change evolved to accentuate behavioral displays (or vice versa), or arose as a signal independent of complex behaviors and evaluate potential phylogenetic constraints on color change. In addition to communicating findings in scientific journals, the researchers will partner with outreach programs at Arizona State University and the South African National Biodiversity Institute to share major research findings via customized learning activities for middle school students in Arizona and South Africa. To better understand whether elaborate behavioral displays evolved before, after, or concurrently with complex color change signals, the researchers will measure natural suites of intraspecific behavioral (i.e. aggressive/submissive) and color signals in 12 species of dwarf chameleons using high-definition video cameras to record staged, aggressive interactions between conspecifics in each species natural habitat. Still photos of the animals, concurrently with video, will be taken during aggressive trials and colorimetric data will be collected throughout behavioral displays and bouts of rapid color change. Felsenstein's independent contrasts and phylogenetic generalized least squares (PGLS) analysis will be used to evaluate the evolutionary relationships between multiple aspects of display colorimetrics and display behaviors, and the strength of the phylogenetic signal will be evaluated for all color and behavioral signals. Lastly, the program Mesquite will be used to reconstruct ancestral states of behavioral displays and color signals in an attempt to disentangle the order and patterns of signal elaboration.