DISSERTATION RESEARCH: The Relative Roles of Chemical and Visual Communication in Heliconius Butterflies

由于化合物使它们变得不好吃，各种各样的动物物种享有相对安全的捕食者。这类物种通常会发出警告信号，捕食者会学会躲避。在许多情况下，无毒物种已经进化到利用这一点，通过模仿不好吃的颜色，形式，行为或气味来欺骗捕食者。或者，不同有毒物种的警告信号可能会趋同，从而减少训练捕食者的成本。尽管对拟态的起源和稳定性进行了大量的理论和实证研究，但对共同拟态（两个或多个相互模仿的物种）之间的相似性可能为物种识别和物种内的交流造成的冲突知之甚少。蝴蝶，表现出许多模仿的例子，是一个很好的模型系统来研究这种信号冲突。这些昆虫通常使用视觉线索来寻找和识别配偶，翅膀颜色图案的差异通常可以防止交配错误，使密切相关的物种在生殖上隔离。同时，这种颜色也可以用作有毒物种的反捕食警告信号。当共存的模仿物种已经收敛在翅膀的颜色模式，作为警告信号，种间模仿和种内识别之间的冲突是可能的。在这种情况下，转向替代识别线索的形式嗅觉信号或交配策略，减少识别冲突的可能性是预期的。该项目的主要目标是确定识别机制，减少信号冲突，以及它们在Heliconius蝴蝶密切相关的物种之间的模仿进化中的作用。为了解决这些问题，首先将确定女性腹部气味中的主要化合物，以测试信号是否以预测的方式变化，以减少具有相似颜色的物种之间的冲突。然后，选择实验和化学分析将用于确定化学和视觉信号的相对重要性，在一个独特的交配系统所表现出的一些Heliconius物种，蝴蝶在蛹阶段找到潜在的伴侣，从而减少对翅膀图案的依赖识别。更广泛的影响。共同主要研究员是一名拉丁美洲女研究生，她将负责这项工作。这项研究将包括对本科生进行蝴蝶饲养和温室条件下实验的培训。在过去，几个本科生（大多数女性）在实验室培训利用Heliconius模型系统进行自己的研究，以解决原始的科学问题。这项工作还促进了德克萨斯大学（美国）和布伦瑞克理工大学（德国）有机化学研究所的师生之间的国际合作。我们预计至少有三个主要的出版物来自这项研究，并在当地和国际科学会议的共同PI和本科生的参与。该项目由综合有机生物学部和国际科学与工程办公室资助。

A wide variety of animal species enjoy relative safety from predators due to chemical compounds that render them unpalatable. Such species often exhibit warning signals that predators learn to avoid. In many cases, non-toxic species have evolved to take advantage of this by mimicking the coloration, form, behavior, or odor of unpalatable ones to deceive predators. Alternatively, warning signals in different toxic species may converge, reducing the cost of training predators. Despite the large amount of theoretical and empirical work on the origins and stability of mimicry, very little is known about the conflicts that similarities between co-mimics (two or more species that mimic each other) might create for species recognition and communication within either species. Butterflies, show numerous instances of mimicry, and are a good model system to study such signaling conflicts. These insects generally find and recognize mates using visual cues, and differences in wing color patterns often prevent mating mistakes, keeping closely related species reproductively isolated. At the same time, such colorations may also be used as anti-predatory warning signals in toxic species. When coexisting mimetic species have converged in wing color patterns that are used as warning signals, a conflict between interspecific mimicry and intraspecific recognition is likely. In such cases, a shift towards alternative recognition cues in the form of olfactory signals or mating strategies that reduce the possibilities of recognition conflict is expected. The main goal of this project is to identify recognition mechanisms that reduce signal conflict, and their role in the evolution of mimicry between closely related species in Heliconius butterflies. To address these objectives, first the main compounds in female abdominal odors will be identified to test whether signals vary in the way predicted to reduce the conflict between species with similar colorations. Then, choice experiments and chemical analyses will used to determine the relative importance of chemical and visual signals in a unique mating system exhibited by some Heliconius species, where the butterflies locate potential mates at the pupal stage, thus reducing reliance on wing patterns for recognition. Broader impacts. The co-PI, who will be conducting the work, is a female Latin American graduate student. The research will involve training of undergraduates, in butterfly rearing and experimentation under greenhouse conditions. In the past, several undergraduates (the majority women) trained in the lab have made use of the Heliconius model system to conduct their own research to address original scientific questions. This work also promotes international cooperation between students and faculty at the University of Texas (USA) and the Institute of Organic Chemistry, TU Braunschweig (Germany). We anticipate at least three major publications derived from this research, and the participation of the co-PI and undergraduates in local and international scientific meetings. This project is funded by the Division of Integrative Organismal Biology and the Office of International Science and Engineering.