Collaborative Research: RUI: From Molecules to Mating: An Integrative Approach to Understanding Chemical Signal Evolution in Fireflies

动物个体之间的交流对生存和繁殖至关重要。在动物之间，交流信号的多样性令人难以置信，并且使用了从视觉到嗅觉的各种感官。这个项目试图确定在魅力十足的昆虫群萤火虫中，不同物种之间的信号是如何以及为什么不同的。虽然公众最熟悉的是它们在温暖的夏夜发出的闪光信号，用来寻找和定位配偶，但许多种类的萤火虫在成年后已经失去了发光的能力。与有光的萤火虫不同，这些“未亮的”成年萤火虫在白天活动，研究表明它们利用嗅觉来探测潜在伴侣的化学信号（信息素）。通过比较使用光信号和信息素信号的北美萤火虫物种，有可能确定与转换信号模式相关的化学，遗传和行为变化的共同模式。在这个项目中产生的资源将极大地扩展萤火虫的基因组工具，使进化、天然产物和保护研究取得实质性进展。识别出的信息素可以为监视受威胁的未发光萤火虫种群开辟新的可能性，否则这些种群就很难进行人口普查。萤火虫也为公众宣传提供了一个理想的机会，因为它们是有魅力的昆虫，吸引了公众的兴趣。在宾夕法尼亚萤火虫节期间开发昆虫生物学和保护教育模块，以及在艺术和文化中开展跨学科的萤火虫社区规划，将昆虫的科学和影响带给公众。在自然界中，交配信号是多种多样的，即使是近亲物种也可以采用截然不同的信号策略。为了了解是什么产生了这种多样性，我们必须了解控制不同分类群信号模式变化的基本机制和进化过程。萤火虫是甲虫科的一种，以其夜间发出的光信号而闻名，这些光信号主要用于识别配偶和选择配偶。虽然所有种类的萤火虫的幼虫都会发光，但只有一些种类的萤火虫在成年后会发光。这些“不发光”的成年萤火虫是昼行性的，可能使用远距离和短距离的信息素来寻找配偶。在北美的分类群中，光通信的丧失和化学信号的二次获得似乎分别发生过好几次。这些自然复制有助于探索伴随主要交配信号模式进化转变的分子和行为变化。(i)用不同的信号模式对亲缘关系密切的物种的挥发性和表皮信号化合物进行表征，将检验化学成分是否在未光照的分类群中多样化。下一代测序将能够检查化学储备多样化是否伴随着化学感觉受体的相应多样化，并确定萤火虫进化枝之间信号模式转换的趋同途径。功能表征研究将直接将化学感觉受体基因与特定的交配信息素成分联系起来。研究具有单峰信号极端差异的生物系统中的进化信号模式切换，为开发模式和预测提供了独特的机会，从而推进更复杂的多峰信号的研究。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Communication among individual animals is essential for survival and reproduction. Across animals, communication signals are incredibly diverse and employ a variety of senses, ranging from vision to smell. This project seeks to determine how and why signals differ among species in the charismatic insect group, the fireflies. While the public is most familiar with their flashing signals on warm summer nights, used to find and locate mates, a number of firefly species have lost the ability to produce light as adults. Unlike their lighted counterparts, these “unlighted” adult fireflies are day-active, and studies suggest that they use smell to detect the chemical signals (pheromones) of potential mates. By comparing North American firefly species that use light versus pheromone signals, there is the potential to identify common patterns in the chemical, genetic, and behavioral changes associated with switching signal modes. The resources produced during this project will dramatically expand genomic tools for fireflies, enabling substantial advances in evolutionary, natural products, and conservation studies. The pheromones identified can open up new possibilities for surveillance of threatened unlighted firefly populations that are otherwise relatively difficult to census. Fireflies also offer an ideal opportunity for public outreach, as they are charismatic insects that draw public interest. Development of educational modules in insect biology and conservation during the Pennsylvania Firefly Festival and interdisciplinary community programming on fireflies in art and culture will bring the science and impact of insects to the public.In nature, mating signals are diverse and even closely-related species can employ strikingly different signaling strategies. To understand what generates this diversity, we must understand the fundamental mechanisms and evolutionary processes that govern signal mode change across taxa. Fireflies, in the beetle family Lampyridae, are renowned for their nocturnal light signals that function primarily in mate recognition and choice. While the larvae of all firefly species emit light, only some species emit light as adults. These “unlighted” adult fireflies are diurnal and likely use long- and short-distance pheromones to find mates. In North American taxa, the loss of lighted communication and secondary gain of chemical signals appears to have occurred independently several times. These natural replicates facilitate the exploration of the molecular and behavioral changes that accompany an evolutionary switch in primary mating signal mode. (i) Characterization of volatile and cuticular signaling compounds from pairs of closely related species with contrasting signal modes will test whether chemical repertoires diversify in unlighted taxa. (ii) Next generation sequencing will enable examinations of whether chemical repertoire diversification is accompanied by corresponding diversification of chemosensory receptors, and identify convergent pathways for signal mode switching among firefly clades. (iii) Functional characterization studies will directly link chemosensory receptor genes to specific mating pheromone components. Investigating evolutionary signal mode switches in an organismal system with extreme differences in unimodal signals offers a unique opportunity to develop patterns and predictions that advance the study of more complex multimodal signals.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.